This is the digital version of Endodontic Practice US Magazine, the March April 2013 issue
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ORTHOPHOS ® XG 3D • Visualize canal anatomy prior to treatment • MARS for better diagnosis around metal • Easy patient positioning Learn more at Sirona3D.com clinical articles • management advice • practice profiles • technology reviews March/April 2013 – Vol 6 No 2 Long-term treatment of root fractures Drs. Jozef Mincík and Marián Tulenko Practice profile Dr. John R. Hughes Top ten tips # 6 Magnification and illumination Dr. Tony Druttman CBCT within endodontics: an introduction Dr. Navid Saberi PROMOTING EXCELLENCE IN ENDODONTICS Corporate profile Coltene: Growth helps fund innovation PAYING SUBSCRIBERS EARN 24 CONTINUING EDUCATION CREDITS PER YEAR! New instruments for root canal negotiation and preparation Drs. Peet van der Vyver and Casper Jonker
Science+Business Media. The publisher’s written consent must be obtained before any part of this publication may be reproduced in any form whatsoever, including photocopies and information retrieval systems. While every care has been taken in the preparation of this magazine, the publisher cannot be held responsible for the accuracy of the information printed herein, or in any consequence arising from it. The views expressed herein are those of the author(s) and not necessarily the opinion of either Endodontic Practice or the publisher.
Should endodontics remain a specialty?Of course we endodontists would all reply with a resounding “Yes!” but it’s not quite that easy — in fact, we were almost decertified back in the late 1980s! As you probably know, every 10 years, the American Dental Association (ADA) requires that each dental specialty submits the reasons why the specialty is necessary. Fortunately, we were recertified a couple of years ago due, in part, to the generous efforts of our AAE Foundation, which has funded research to expand the envelope of endodontic knowledge. On a more personal level, what are we endodontists doing (or should be doing) to reaffirm the need for our specialty? Our AAE appoints a committee to prepare a document that will be sent to the ADA highlighting the distinguishing practice guidelines that justify our specialty existence; these guidelines have to reflect what all endodontists are capable of performing. In fact, the AAE has position papers on the breadth and depth of what general dentists and the public should expect from a practicing endodontist. With this introduction, I have a few questions for my endodontic colleagues: Are we all using CBCT (cone beam) when periapical radiographic images are insufficient to make an accurate diagnosis? We don’t necessarily need to buy a CBCT (they are costly) because there are so many dental X-ray centers so nearby. By employing CBCT, when appropriate, we can make more sophisticated and accurate diagnoses. After all, who but we endodontists are better trained to diagnose vertical root fractures? How about the more elusive (occult) incomplete vertical root fractures? But the subtext of this question about CBCT leads to another question: do we endodontists have sufficient training acquired either through a rigorous post-graduate endodontic program or through continuing education programs to interpret CBCT findings? In 2013, there is a reasonable expectation by general dentists and the patients we serve that endodontists should know when to employ and how to interpret CBCT. When it comes to a complex diagnosis (e.g., atypical facial pain) that presents ostensibly as “toothache,” our advanced training in history gathering and testing enables us to recognize this uncommon entity. We endodontists must reaffirm through our clinical diagnostic acumen that recognizing complex diagnostic entities is another area that distinguishes our specialty from general dentistry. Accurate diagnosis is part of the foundation of our specialty, and this in turn, leads to accurate and appropriate treatment planning. All of us have seen countless cases that were misdiagnosed which, of course, led to inappropriate treatment or even worse, mistreatment. If an injured patient files a complaint against an endodontist alleging negligent treatment, it is quite likely Plaintiff’s counsel will inquire if the endodontist used CBCT leading to the diagnosis and treatment plan — and if not, why not? Of course, not every case we treat requires CBCT; however, if we fail to employ CBCT when it is indicated for diagnosis or treatment planning, we may expose ourselves to claims of negligent care. Pulp regeneration is not merely science fiction, it’s a science fact based on many fine studies published in our peer-reviewed endodontic journals. Are we endodontists prepared to employ pulp regeneration when an appropriate case presents in our office? After all, our ability to stimulate pulp regeneration is another distinguishing feature that sets us apart from the general dentists’ skill-set. When symptoms subside, patients may become dilatory about returning to their general dentist for a final restoration, or the general dentist may delay restoring the endodontically-treated tooth. Thus, I would submit that we endodontists should also place final restorations in our access openings because we know, through many papers published in endodontic journals, that there are countless failures due to coronal leakage around provisional restorations. Every day we are in practice, we must demonstrate our sophisticated Standard of Endodontic Excellence to justify endodontics as a specialty!
Stephen Cohen, MA, DDS, FICD, FACDDiplomate, American Board of Endodonticswww.cohenendodontics.com
TABLE OF CONTENTS
ClinicalElectronic root canal
measurements using Endo-Eze
Quill, Root ZX mini, Root
ZX II, and SybronEndo Mini
apex locators — an in vitro
comparison with actual canal
length
Drs. Carlos A. Spironelli Ramos,
Renato de Toledo Leonardo,
Richard D. Tuttle, and Bruno Shindi
Hirata, study the location of the
suitable apical file position ..........12
Long-term treatment of root
fractures
Drs. Jozef Mincík and Marián
Tulenko discuss the long-term
treatment of root fractures with
Rebilda Post System ..................16
Endodontics in focusTip number 6 – Magnification and
illumination
Dr. Tony Druttman looks at the
importance of magnification and
illumination in the practice of
endodontics ...............................20
2 Endodontic practice Volume 6 Number 2
Practice profile 6Dr. John R. Hughes: Privileged to serveDr. John Hughes discusses restorative dentistry, the importance of sharing with
colleagues, and his fulfilling humanitarian efforts.
Corporate profile 10Coltene®: Growth helps fund innovationThe COLTENE ENDO group offers a complete product lineup, ranging from
diagnostics, isolation, drying and filling products, to post and core build-up
materials.
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What can you tell us about your background?I was born in the back bedroom of the church parsonage of the First Baptist Church, Gene Autry, Oklahoma. My father was a minister, my mother was a full-time mom, and both were the children of dirt farmers in Oklahoma and Texas. We were poor as church mice, but I did not know it! I was the second of four, a total nerd, and moved to different locations every 4 to 5 years. I took 18 to 21 hours per semester at Oklahoma Baptist University where I majored in chemistry and math with a physics minor. I applied to one dental school at the end of my junior year and graduated from The University of Missouri at Kansas City 4 years later. I married my wife, Thompson, a designer for Hallmark Cards, a month later. Still married to the same wonderful woman after 46 years! I was a restorative dentist in Kansas City for 15 years and dealt with my mid-life crisis by going to Boston University to study endodontics under Dr. Herb Schilder. Two years later, at the end of the residency, we decided we didn’t want to be cold any more. We came to Tucson, Arizona, where I started Southern Arizona Endodontics (SAE) 30 years ago, a practice with 12 endodontists (one retired), four locations and 55 of the best employees in southern Arizona.
Is your practice limited to endodontics?SAE is an endodontics-only specialty practice. I think most endodontists’ drift toward implants represent a lack of busyness rather than a love of implants. We would rather be great at endo than good at endo and implants.
Why did you decide to focus on endodontics? My initial interest in endodontics was driven by a hope for more control of the result of my efforts. There is no tougher professional task in my mind than being a good restorative dentist. Great long-term success depends on the lab and patient attention to detail. The greatest effort of the dentist is compromised by too many things outside of his control. Endodontics is certainly one of dentistry’s most predictable procedures and one that is most dependent on operator excellence.
How long have you been practicing, and what systems do you use?I started restorative dentistry in 1966 and endodontics in 1983. Endodontics has seen many changes in that span. The growth of new products and procedures has been almost exponential. In our office, we have all of the bells and whistles. There
is probably nothing one of us has not tried. There is a wide variety of the types of rotary instruments we use. We all end up using vertical compaction of warm gutta percha for stuffing the root system. While we have a lot of great systems at our disposal, most that are advertised to make the process easier also lend themselves to misuse. Faster and easier rarely translate to more predictable and better outcomes. Regardless of the systems you use, they require knowledge of the root canal system you are invading, an understanding of the complexity of that system, and the determination to seal it well. Ninety-nine percent of today’s graduates are well- informed and well-trained endodontists. The systems they are most deficient in are the systems associated with the attraction and nurturing of referral sources. That is an area that spells success or failure for many offices. Failure to thrive with today’s high debt loads is not uncommon.
What training have you undertaken?I was fortunate to train under the firm control of Dr. Herb Schilder. I was fortunate to also study with a group of 33 exceptional residents; 11 in my class, 11 in the class before me, and 11 in the class behind. The majority of my training came from the residents around me. We
Dr. John R. Hughes
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Privileged to serve
Alexi, an orphan, and I in an orphanage in Tijuana, Mexico
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saw more, learned more, and experienced more by the shear numbers of endodontic procedures we were exposed to. Some of the best endodontists I have known came out of those 33 people. I also was involved with a mastermind group of 10 or 12 endodontists from all over the United States for many years that met every 6 months to compare successes, frustrations, and challenges. That really shortened the learning curve for all of us and exposed us to a lot of the movers and shakers in the profession. In addition, I have been a student of business systems and applications. Part of our success has been our attention to detail outside of the root system. Henry Wadsworth Longfellow wrote:
The heights of great men, reached and keptWere not obtained by sudden flight,But they, while their companions slept,Were toiling upwards in the night.
Success or mastery is not a 9-to-5 endeavor. Success favors those who entertain the thoughts and wisdom of others. We all drink from wells others have dug.
Who has inspired you?It would be impossible to be around Dr. Herb Schilder without being inspired. His commitment to the mastery of endodontics was and is a frequent reflection. The rest of the dental list is rather long, but includes Drs. Pankey, West, Ruddle, Pannkuk, Melnick, Stropko, Yu, and Sam Marescalco, the best restorative dentist I ever knew. My wife, Thompson, is also a source of great inspiration to me. Though visually impaired, her outlook on life, her commitment to the joy of others, and her love of her grandchildren bring a smile to my mind.
What is the most satisfying aspect of your practice?I would say the growth of those I work with. We have had dental assistants who have decided to go back to school and on to dental school. Two of our staff leaders have been with SAE for over 20 years, and many have excelled with us for 10 years or more. The strength of our culture is the result of the commitment our workforce has to treat patients and each other with kindness, courtesy, and respect. I have never seen a staff more aligned in the pursuit of excellence both in and out of the tooth.
Professionally, what are you most proud of?For many years, we have maintained a relationship with over 350 different dentists who refer to our group. We track our referrals very closely. If we see a decline, we are quick to see where we are failing them. We are in the relationship business. The lengths we travel to maintain that connection and the service we perform for their patients consistently is the result of systems we have had in place for many years. We do good endo, but most offices do good endo. We really excel before and after treatment, from our followup to our commitment to see all patients who are in pain that same day.
These may look like young fillies, but they are workhorses I have worked with for a combined total of over 65 years!
What do you think is unique about your practice?The quality of care we extend to our patients from the time of their contact with us to follow up after they leave our office. We work hard to treat every one as if he/she is a guest in our home; a special person we are privileged to serve.
What has been your biggest challenge?Early on, the biggest challenge was to control our growth to allow us to maintain quality of care in a caring environment. Once our systems were in place, developing
and maintaining our office culture became a priority. We are fortunate to have a first-rate administrator to manage our systems, culture, and priorities. Michael Austin allows us to stay in the operatory with the confidence that outside the operatory, everything is under control.
What would you have become if you had not become a dentist?We are in the widget business. If we are not making widgets, our income stream is threatened. I would have been fascinated with the challenges of management/leadership of a company or service that allowed delegation of responsibilities without affecting the outcome. I think an attorney with an MBA would allow for a great latitude of opportunities.
What is the future of endodontics and dentistry?I am excited about the challenges that lay before us. When I look at where dentistry has come during my watch, I would hesitate to guess where it is going. Just 15 years ago, implants were considered risky business. Now, in the right hands, they are predictable. I don’t see them replacing endodontics, but it has allowed us an alternative to treating marginal teeth. We will continue to be faced with access to care issues. Products and solutions will continue to evolve. I think success will always follow quality of care, especially in dentistry.
What are your top tips for main-taining a successful practice?You never get a second chance to make a good first impression. Always have your best telephone personality answering the phone. There is no position in your practice for a person with a bad attitude. A person with average skills and a great attitude always trumps a very skilled person with poor attitude. We hire attitude and train skills. You must be very intolerant of poor culture. We work very closely with patients who are our guests at a challenging time in their life. They do not need to be exposed to staff that is not harmonious and supportive of each other. Kindness, courtesy, and respect rules the day. Your office requires management and leadership. Managers focus on systems and structure, leaders on development. Managers push; leaders pull. Management involves efficiency; leadership involves effectiveness. Peter Drucker once commented that “with the emergence
Dr. Hughes and his colleagues at Southern Arizona Endodontics
8 Endodontic practice Volume 6 Number 2
PRACTICE PROFILE
TOP FAVORITES
My wife, Thompson
My two sons, Justin and Cole, and my daughter Wendy
My four grandchildren, Hailey, Tanner, Tenley, and Britney
My partner of 25 years, Dean Hauseman
DEXIS®: There are several good digital radiograph systems available. I think DEXIS is the cream of the crop.
Dentrix: We have over 75 work stations, 67 users, over four locations. This software system gives us real time access to any chart in any location. It also works seamlessly with DEXIS. A great pairing.
Tulsa Dental: We are, I assume, one of Tulsa’s largest accounts and biggest fans! They seem to always be there when the “next big thing” is introduced. They have a large variety of rotary instruments that fit our group perfectly!
Roydent™ Dental Products: We have used Roydent’s files and reamers forever.
Smart Practice®: The best, most economical, suppliers of gloves. Very service oriented.
A pro bono work in progress, we built in 3 1/2 days Getting ready to raise a home for another family Last project’s work crew
of the knowledge worker, the challenge is not to manage people; the task is to lead them.” That involves allowing staff to contribute to the decision-making process. They work harder to implement ideas when they are included in the process. A staff that is in alignment with decisions they help develop, “buy in” to the success of the office.
What advice would you give to budding endodontists?First, join or start a mastermind group. It should be comprised of endodontists outside of your geographic area. Our group met twice a year for many years. We each brought copies of all of the current printed material in our office (such as referral pads, letterheads, post-op correspondence) and distributed them with the agreement that we could mimic anything in our office. Sharing and discussing challenges and solutions greatly reduces the learning curve. We spent Friday on tooth stuff and Saturday on management, leadership, and interface with referring offices. Second, know what your gift is, what your strengths and weaknesses are. Those affect how you can best thrive. There are really just five or six ways you can practice. Each has pluses and minuses; some attract specific personality types, or fill specific needs and wishes of the dentist. Most practices are a combination of one or two of the following.1) Government services: Veterans
Administration, Indian Health Service, armed services, etc. These involve somewhat of an 8-to-5 group involvement with retirement after a fixed number of years.
2) Education/Research, with an intermural practice: Schools need endodontists.
3) Develop products and/or systems, lecture, become an “authority.”
4) Underserved area: These are becoming hard to find.
5) Emergency practice: See all people in pain.
6) Make the experience so compelling, exceeding the expectations of the patient and the referring office.
SAE combines the last two. We strive to be able to say, “Send them right over!” We know that frequently the patient isn’t hurting, the dentist is! We don’t judge whether he made a good decision in sending them; we are happy to triage the patient. Rarely does the patient require immediate treatment. If you are swamped, you medicate them. You can say, “My, my, my, I bet that hurts. We are going to get you on some antibiotics that will make you feel better in a day or two. In the meantime, we will give you something for the pain to get you some rest. If we tried to do something today, I am afraid we would not be friends afterward! We will first get the swelling down and get you comfortable.” Or you can incise and drain or open the tooth. None of that takes a long time. Then, schedule them in the next week. They will be happy that you saw them. There are three great things about emergency patients; 1) They are thrilled to be seen, 2) they are referred, not because of the degree of difficulty, but because of the referring dentist’s lack of time, and 3) the dentist feels like he is a stud, and he can say, “they will see you today.” Once they are in our office, it is our chance. It is our job to pamper them from the moment they step in our office to the time they leave. You can say it is not necessary, I know it is not necessary! You do it because you are building a practice that is exceptional. People do not know good endo, but they know how they were treated, and how they felt when they left. When they think of your office, it should put a smile on their face! Third, don’t get too full of yourself. When was the last time you were impressed by someone who introduced himself/
herself as “doctor?” Your patient knows that you are a doctor…your assistant can introduce you as doctor…but you, use your name. “Hello, I am John Hughes.” That is much more powerful, whether in the office or in social settings. They will find out soon enough that you are a doctor. Charles DeGaulle, former general and president of France, once said, “Graveyards are full of indispensable people.” Keep your eye on possibilities! You must be a rainmaker. Referrals don’t just come; they must be earned.
What are your hobbies, and what do you do in your spare time?I really enjoy pro bono construction in Mexico. When I retire, I hope to build a home every month or so. I now build every March with a group of students from Westmont College during their spring break. It greatly changes the lives of the givers and the receivers. EP
Penetrate La
teral
Canals
and Is
thmus
es
Better T
han N
eedle
Irrigati
on
235 Ascot Parkway | Cuyahoga Falls, OH 44223
Tel. USA & Canada 800.221.3046 | 330.916.8800 | coltene.com
See us at AAE booth # 711
PATENT PENDING
• Distributes and ultrasonically activates sodium hypochlorite to increase debridement of lateral canals and isthmuses
• Ratcheting syringe permits controlled delivery of 0.2 ml of solution with each audible click
Benefits of Continuous Ultrasonic Irrigation:
• Removes significantly more debris from narrow isthmuses better than conventional needle irrigation*
• Significantly increases the penetration of irrigation solutions into lateral canals**
Ultrasonic Irrigator
*Adcock et al, J.Endod. 2011; 37 (4) **Castelo-Baz et al, J. Endod. 2012; 38 (5)
In May 2011, the COLTENE ENDO group formed to consolidate some of the most
widely known endodontic brands under one umbrella, allowing clinicians simplified access to product information. Bringing many widely known brands under one umbrella enables greater focus. The COLTENE ENDO group is comprised of three sites: Altstatten, Switzerland, Langenau, Germany, and Cuyahoga Falls, USA. The American headquarters in Cuyahoga Falls, Ohio is one of the main manufacturing locations for several of the products and the home site for divisional management. Operating as an international team allows the COLTENE ENDO group to cross-pollinate ideas, making products more relevant and uncompromising based on feedback from a broad, multinational group of dentists, universities, and opinion leaders. The COLTENE ENDO group has brought together products from four product lines; Alpen®, ROEKO, Hygenic® and Whaledent. Alpen®, a complete line of diamond and carbide burs, offers endo access products to gain entry into the canal. Celebrating its 100th birthday, ROEKO products like ROEKOSeal continue to be used by a wide dental audience. Another brand of products that performs day in and day out is Hygenic® Endo-Ice®, paper and gutta-percha points. Helping to ensure better isolation with latex and non-latex choices are the industry’s gold standards, Hygenic® Dental Dams and Clamps. For the past 50 years, the ParaPost® and ParaCore have been used in millions of post and core build-ups. Within the COLTENE ENDO product portfolio are everyday endo products used for a wide range of therapies. The merger of brands into one globally managed portfolio allows greater focus on the endodontic field, thereby enhancing customer service and expediting innovation forces.
Endodontic products continue to growThe focus of COLTENE ENDO, to concentrate on bringing together all the products needed to perform endodontic treatment, is helping fuel the overall growth of the entire company. The COLTENE ENDO group has tapped into an ongoing
trend within dental — patients are living longer, thereby necessitating more treatment. In general, older patients have more money, resulting in geriatric dental patients being treated for endodontic ailments like root canals. Moreover, the mission of the COLTENE ENDO group is to focus on filling out their portfolio to offer a wide selection of endodontic products. The Strategic Dental Marketing group agrees that endo product sales are on the rise. Richard Fishbane, Vice President of Strategic Dental Marketing states, “In 2012, the endodontic category of products saw a growth rate that was substantially higher than the overall growth rate for dental products in the U.S. Coltene’s Endo
Division was a major factor in that growth and posted the strongest annualized sales growth of any major endodontic manufacturer in the U.S.” The success of Coltene in 2012 was aided by the strong performance of the endo division.
Investment in R&DEven during the economic downturn of 2008 and 2009, Coltene funded research and development projects, keeping the pipeline full. The COLTENE ENDO group’s development process is collaborative gathering cross-functional input from Asia, Europe, and the Americas. The process starts with investigation of market needs and trends. Customer input enters the
Growth helps fund innovation
10 Endodontic practice Volume 6 Number 2
CORPORATE PROFILE
Coltene North American headquarters, Cuyahoga Falls, Ohio
History of COLTENE ENDO firsts
First high volume casting and metal post manufacturer
First to introduce a silicone endo sealer
First cold flowable root canal sealer
First core build-up material and post cement (ParaCore) to be
indicated as a crown cement
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Operating as an international team allows the COLTENE ENDO group to cross-pollinate ideas, making products more relevant and uncompromising based on feedback from a
broad, multinational group of dentists, universities, and opinion leaders.
development process through opinion leaders, universities, R&D staff, and sales and marketing personnel. Winning ideas are formulated and tested following a rigorous process that ensures new key benefits are included. Validation occurs by testing the product’s properties through internal and external means that also includes giving products to universities and key opinion leaders to test. Coming out of the COLTENE ENDO group are three market-focused products helping the endodontist and general practice dentist drive successful clinical outcomes. The Coltene Hyflex® CM™ NiTi files offer clinicians up to 300% more resistance to cyclical fatigue, helping reduce the incidence of file separation. HyFlex® CM NiTi files have been manufactured utilizing a unique process that controls the material’s memory, making the files extremely flexible but without the shape memory of other NiTi files. This gives the file the ability to follow the anatomy of the canal very closely, reducing the risk of ledging, transportation, or perforation. CanalPro™ is another new complete
grouping of products introduced by the COLTENE ENDO team. The complete system of color-coded syringes provides an easy way to organize and identify different types of irrigants and solutions, helping to increase safety and minimize the chance of syringe swap. The CanalPro™ line offers a complete selection of endodontic irrigation tips. CanalPro™ endodontic solutions are engineered to optimize the time spent on irrigation, giving the clinician the best approach for cleansing canals and achieving the best outcomes. CanalPro™ irrigation solutions come in four formulas: CanalPro™ NaOCl EXTRA, NaOCl, EDTA and CHX-Ultra. CanalPro™ helps complete the COLTENE ENDO lineup, allowing the practitioner four separate products to help cleanse the canal and eliminate debris. Newly introduced GuttaFlow®2 is the second generation of the first cold flowable root canal filling system that combines gutta percha with a sealer. The delivery system is an industry standard 5ml syringe making dispensing convenient and simple. GutttaFlow®2 requires no heating, no
condensation, and no plastic carriers to transport material into the canal. The COLTENE ENDO group offers a complete product lineup, ranging from diagnostics, isolation, drying and filling products, to post and core build-up materials. What makes the mission of the newly formed COLTENE ENDO group more relevant than ever, is discovery of new techniques and products to solve everyday problems. New product innovation that saves valuable chair time while driving improved patient outcomes is what matters most. Successful tried-and-true products are being surrounded with incremental product innovations to make the endodontist and general practice dentist’s job faster to complete, freeing up valuable time for everyone. Coltene/Whaledent, Inc.235 Ascot ParkwayCuyahoga Falls, OH 44223800-221-3046
This information was provided by ColTene endo.
EP
Summary The purpose of this study was to determine the ability of four apex locator devices to 1) indicate precisely the foramen exit position correctly, 2) provide fundamental data for working length determination, and 3) indicate intermediate points. Thirty extracted maxillary central incisors were used in this study. Measurements were taken using the new Endo-Eze® Quill (Ultradent, USA), Root ZX® mini (J. Morita, Japan), Root ZX® II (J. Morita, Japan), and SybronEndo Mini (Sybron Dental Specialties, USA) apex locators. An analysis of variance (ANOVA) was used to evaluate the measurements, and no statistically significant differences were found between the electronic measurements of the devices and the actual canal length at the foramen point. This study also showed that none of the devices demonstrated accurate measurements at intermediate points.
Introduction The establishment of the correct apical limit of instrumentation is accepted as one of the most important operative procedures
in endodontics. Determination of accurate working length has a profound influence on ideal canal cleaning and shaping, microbial disinfection, and appropriate sealing of the root canal system. The location of the suitable apical file position has constituted a persistent challenge in clinical endodontics. Radiographs are commonly used to determine the working length. However, radiographic assessments of the working length may prove inaccurate, depending on the direction and the extent of the root curvature, and the position of the apical foramen in association with the anatomic apex. By measuring the electrical properties of the apical third of the root canal, such as capacitance and impedance, it should be possible to detect the canal terminus. The root canal system is surrounded by dentin and cementum, which are insulators to electrical current. At the apical foramen, there is a small orifice in which conductive materials within the canal space (e.g., tissue and fluid) are electrically connected to the periodontal ligament that is itself a conductor of electric current. Thus, dentin, along with the tissue and fluid inside the canal, forms a resistor, the value of which depends on their dimensions and inherent resistivity. When an endodontic file penetrates inside the canal and approaches the apical foramen, the resistance between the endodontic file and the foramen decreases because the effective length of the resistive material (dentin, tissue, and fluid) decreases. Along with resistive properties, the structure of the tooth root has capacitive characteristics. Therefore, various electronic methods have been developed that use a variety of methods to detect the canal terminus. While the simplest devices measure resistance, other devices measure impedance using one high frequency, two frequencies, or more than two frequencies. In addition,
some systems use low frequency oscillation and/or a voltage gradient method to detect the canal terminus. Many new electronic foramen locators have become available, resulting in the need to have their accuracies ascertained and compared. Some techniques for determining the endodontic working length have been described and verified scientifically, including the digital tactile sensibility, methods based in radiographic analysis, and electronic methods. The third generation of apex locators are based on analysis of relative impedance changes over frequency, and preliminary published studies indicated reliable and accurate measurements of the position of apical foramen. Despite being based on the same third generation method of operation, the different models to be tested differ as to the number of frequencies used to calculate the impedance variation. The current study’s aim is to determine if the new Endo-Eze Quill, Root ZX II, Root ZX mini, and SybronEndo Mini present accurate measurements of foramen position (canal length) and intermediate positions to calculate working length.
Electronic root canal measurements using Endo-Eze Quill, Root ZX mini, Root ZX II, and SybronEndo Mini apex locators — an in vitro comparison with actual canal length
12 Endodontic practice Volume 6 Number 2
CLINICAL
Drs. Carlos A. Spironelli Ramos, Renato de Toledo Leonardo, Richard D. Tuttle, and Bruno Shindi Hirata, study the location of the suitable apical file position
Carlos A. Spironelli Ramos, DDS, MSc, PhD, is a specialist in Endodontics; Professor, Roseman University of Health Sciences, College of Dental Medicine, South Jordan, Utah; and Master and PhD in Endodontics, University of São Paulo, and Ultradent R&D Endodontic Segment Manager.
Renato de Toledo Leonardo, DDS, MSc, PhD, is a specialist in Endodontics; former Head and Chairman, Department of Restorative Dentistry, Araraquara Dental School-UNESP; Master in Endodontics, PhD in Pathology, University of São Paulo; Visiting Professor, University of Texas at San Antonio, Texas; and Invited Professor, Universitat Internacional de Catalunya, Spain.
Richard D. Tuttle, DDS, is Col. USAF Ret., R&D Clinical Division Manager, and Clinical Applications Advisor.
Bruno Shindi Hirata, DDS, MSc, is a specialist in Endodontics and Master in Endodontics, State University of Londrina, Brazil.
Figure 1: Endo EZE Quill Apex locator, Ultradent, USA
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Materials and methods Selection of extracted teeth This study was performed in accordance with the guidelines issued by the Department of Health, State of Paraná, Brazil, and after approval by the State University of Londrina’s Ethics in Research Committee.
Figure 2: A digital caliper (Mitutoyo, Japan) showing a value corresponding to the actual length of the canal and the electronic measurements of the canal. The measure-ments were taken from the top of the rubber stopper to the base of the handle
Figure 3: Cross section showing the placement of the file in the specimen during the measurements and the dis-tance measured (line AB) from the base of the file handle to the top of the rubber stop
Recently extracted human maxillary central incisors stored in 2.5% glutaralde-hyde solution were used in this study. After evaluating the canal shape with mesiodistal and buccolingual radiograph films, teeth with previous endodontic treatment, complicated anatomy, external root resorption, immature root, and apical
foramen diameter up to 4.0X10-2 mm were excluded, leaving 30 teeth to be used for this study. The selected teeth were immersed in 5.25% sodium hypochlorite solution for 15 minutes. Calculus and soft tissue debris were removed with a scaler, and the teeth were washed thoroughly with tap water. The teeth were then stored in 100% humidity at a temperature of 36ºC until the tests were conducted. All teeth specimens were cut horizontally at the cemento-enamel junction with a diamond disc (Extec® 12205, Extec Corp.) mounted in a precision saw (IsoMet® 1000, Buehler Ltd). The canal orifice at the cemento-enamel junction cut was used as the reference point for all measurements.
Visual determination of the actual canal length In order to determine a value corresponding to actual canal length of the specimens, a No. 10 K-File (Maillefer, Switzerland) was introduced into the canal until the tip of the file reached an imaginary line connecting the edges of the foramen exit. The silicon stop was lowered to the cemento-enamel
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Table 1: Mean and standard deviation of the distances between the electronic measurements at point 0.0 (foramen exit) and actual length
Table 2: Mean of the distances and standard deviations (SD) between the points measured (point 0.0, 0.5, 1.0, 1.5, 2.0, 2.5, and 3.0) and actual lengths. NS means with no statistical difference between the compared values (ANOVA). SS means statistical difference between groups
Table 3: Mean of the distances between the intermediate points measured (0.5, 1.0, 1.5, 2.0, 2.5, and 3.0). NS means with no statistical difference between the compared values (ANOVA, p<0.05). SS means statistical difference between groups. There were no differences among the devices studied at 0.0, 0.5, and 1.0. At points 1.5 and 2.0, SybronEndo Mini showed statistical different results comparing with the others
junction cut position. Using a digital caliper (Mitutoyo, Japan), measurements were made from the silicon stop to the base of the handle (Figures 2 and 3). The same methodology was used to determine the electronic measurement’s values.
Electronic determination of the canal length After locating the canal opening using an endodontic probe, the initial instrumentation was made with a No. 10 or 15 K-File (Maillefer, Switzerland), stopping approximately 3 mm short of the temporary working length. In all cases, instrumentation was made using the crown-down technique. All specimens were irrigated abundantly with 2.5% sodium hypochlorite, and the excess liquid was evacuated from the canal before any electronic measurements were taken, according to the device manufacturer’s instructions. Alginate (Alginplus®, Major, Torino, Italy) was mixed following the manufacturer’s instructions, and all of the specimens were individually embedded in alginate. Before electronic measurements were taken, the teeth were removed from the alginate to verify the regularity of the reproduction and the absence of bubbles. Within 2 hours after alginate preparation, the root canal electronic measurements were taken. Each specimen was tested with the four devices by the same operator, and the measurements were recorded. The four devices: Endo-Eze Quill (serial number F1, Figure 1); Root ZX mini, (serial number ZJ062); Root ZX II (serial number VA8025); and SybronEndo Mini, (serial number SC3456) were set up with the contrary electrode in the alginate and the file electrode attached to the file to be introduced into the canal. The devices would determine the canal length from the reference point to the “0” mark (foramen position, 0.5, 1.0, 1.5, 2.0, 2.5, and 3.0), as indicated on the devices. Although some devices were designed to measure canal lengths at varying distances from the apical foramen, measurements to the “foramen” mark were taken first and compared with the actual length’s relative value in order to standardize the procedure for the four devices. For the electronic measurements, a K-File sized for the foramen’s anatomical diameter was introduced gently towards the radicular apical third, until the Endo-Eze Quill showed the green LED indication
(0.0), the Root ZX mini and Root ZX II showed the last green mark before “APEX,” and the SybronEndo Mini showed the green LED indication “APEX.” The same procedure was performed two times for each device. After the foramen position measurements were taken, intermediate point measurements were taken with the four devices. Using a digital caliper (Mitutoyo, Japan), measurements were made between the silicon stop and the base of the handle (Figures 2 and 3). From these measurements, calculations were made of the differences between the relative values corresponding to the actual canal lengths and the electronic device’s measurements of the canal lengths at the foramen position (0.0), and the other positions of (0.5), (1.0), (1.5),
(2.0), (2.5), and (3.0). The statistical analysis for each device was made from this data.
ResultsBecause the specimen sample size was greater than 20, the Kolmogorov-Smirnov nonparametric test was used to compare the sample distribution. It was found that the significance was 0.200, showing a normal distribution of the results. As the distribution was normal, the ANOVA parametric test was used, analyzing the data from the four devices. The significance was 0.066, (p<0.05), showing that there was no statistical difference between the values found comparing electronic measurements at the point 0.0 (foramen positions) and canal’s actual length. Intermediate points, from
2. Rambo MV, Gamba HR, Ratzke AS, Schneider FK, Maia JM, Ramos CA. In vivo determination of the frequency response of the tooth root canal impedance versus distance from the apical foramen. Conf Proc IEEE Eng Med Biol Soc. 2007;570-573.
3. Ricucci D, Langeland, K. Apical limit of root canal instrumentation and obturation, part 2. A histological study. Int Endod J. 1998;31(6):394-409.
4. Ricucci D. Apical limit of root canal instrumentation and obturation, part 1. Literature review. Int Endod J. 1998;31(6):384-393.
6. Nekoofar MH, Ghandi MM, Hayes SJ, Dummer PM. The fundamental operating principles of electronic root canal length measurement devices. Int Endod J. 2006;39(8):595–609.
7. Carneiro E, Bramante CM, Picoli F, Letra A, da Silva Neto UX, Menezes R. Accuracy of root length determination using Tri Auto ZX and ProTaper instruments: an in vitro study. J Endod. 2006;32(2):142-144.
8. Welk AR, Baumgartner JC, Marshall JG. An in vivo comparison of two frequency-based electronic apex locators. J Endod. 2003;29(8):497–500.
9. Ponce EH, Vilar Fernández JA. The cemento-dentino-canal junction, the apical foramen, and the apical constriction: evaluation by optical microscopy. J Endod. 2003;29(3):214–219.
10. Herrera M, Abalos C, Planas AJ, Llamas R. Influence of apical constriction diameter on Root ZX apex locator precision. J Endod. 2007;33(8):995–998.
11. Olson DG, Roberts S, Joyce AP, Collins DE, McPherson JC III. Unevenness of the apical constriction in human maxillary central incisors. J Endod. 2008;34(2):157–159.
12. ElAyouti A, Lost C. A simple mounting model for consistent determination of the accuracy and repeatability of apex locators. Int Endod J. 2006;39(2):108–112.
13. Venturi M, Breschi L. A comparison between two electronic apex locators: an ex vivo investigation. Int Endod J. 2007;40(5):362-373.
14. Ounsi HF, Naaman A. In vitro evaluation of the reliability of the Root ZX electronic apex locator. Int Endod J. 1999;32(2):120-123.
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0.5 to 3.0, showed statistical differences between electronically measured points and actual corresponding points in all devices studied. Table 1 shows the mean and standard deviation of the distances between the electronic measurement at point 0.0 of each device and the actual length. Table 2 shows the mean of the distances between all points measured (point 0.0, 0.5, 1.0, 1.5, 2.0, 2.5, and 3.0) and relative actual length values. There was no difference between all device’s electronic measurements at point 0.0 and the actual root canal length (p<0.05). Statistical analysis showed differences (p<0.05) between all the intermediate points electronically measured by all devices tested and the actual intermediate values. Table 3 shows the mean of the distances between intermediate points measured using the tested devices (point 0.5, 1.0, 1.5, 2.0, 2.5, and 3.0). Comparing results among the intermediate electronic measurements of Endo-Eze Quill, Root ZX mini, and Root ZX II showed there were no statistical differences between the results. Nevertheless, at points 1.5 and 2.0, SybronEndo Mini showed statistically different results when compared with the other devices.
ConclusionIt was observed that no electronic measurement of any of the devices used in this study was beyond the real position of the apical foramen, maintaining the apical biological limit parameters. The results are in agreement with studies that used similar third-generation apex locators. Comparing the electronic measure-ments at the foramen positions, indicated by the four apex locators studied (Endo-Eze Quill, Root ZX mini, Root ZX II, and SybronEndo Mini) with the actual root canal’s lengths found no statistically significant differences. The intermediate points do not appear to be accurate because they showed statistically significant differences as compared to the actual intermediate points. These results are in agreement with the Rambo, et al., study, which showed that electronic apex locators are accurate when used at the foramen reference point only. EP
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Root fractures must be regarded as a form of complex trauma because they
affect both the dental hard tissue, and the periodontal and pulpal tissue. They result from powerful forces with compression zones acting in the root region. The consequence of fractures is that the tooth is split into a coronal and an apical fragment. In regards to the level at which the fracture occurs, a distinction is made between fractures in the apical, middle, and cervical third of the root. It is known that young patients, in whom root growth is not yet complete, have the best prospects of the fracture healing. Other factors that are favorable to the healing process include a positive sensitivity test at the time of the accident, no dislocation, and no pronounced mobility of the coronal fragment. In the absence of dislocation, there is a danger of the fracture not being detected, and therefore, imaging at two levels is necessary for the purpose of diagnosis (von Arx, Chappuis, Hänni, 2007). The recommendation that a root fracture should be treated with rigid splinting for several months has long since become obsolete. No positive effect on the healing pattern in the region of the fracture gap was demonstrated with splinting for longer than 4 weeks (Cvek, Andreasen, Borum, 2001). The factors determining the choice of treatment are the location of the fracture,
the nature and degree of dislocation of the coronal fragment, and the stage of root growth. In the case of root fractures located entirely in the intra-alveolar region, the outcome is often favorable. With a root fracture, only the coronal fragment is treated as a rule because the apical portion generally remains vital (Andreasen, Hjorting-Hansen, 1967).
The specific caseIn 1999, an 11-year-old patient came to our practice after a bicycle accident. During the intraoral examination, we found greatly increased mobility of the upper right lateral incisor (UR2) and less pronounced mobility of the maxillary central incisors (UR1, UL1)
without dislocation. The teeth were treated with a wire splint, which was adhesively bonded to the labial surfaces. Two weeks after the initial treatment, the percussion test on the upper right lateral incisor (UR2) was negative. At the same time, sensitivity to percussion was detected. Following trepanation and pulp extirpation, the tooth was filled with calcium hydroxide (Figure 1). Two months after the trepanation, a permanent root canal filling was placed in the upper right lateral incisor (UR2). Incipient obliteration in the apical region, a symptom that often accompanies root fractures, prevented the apex being reached (Figure 2). At the patient’s regular visits to our
Long-term treatment of root fractures
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CLINICAL
Drs. Jozef Mincík and Marián Tulenko discuss the long-term treatment of root fractures with Rebilda Post System
Figure 1: The radiograph shows the root fractures of the upper right lateral incisor (UR2) [root region], the maxil-lary central incisors (UR1, UR2) [apical region], and the upper right lateral incisor (UR2) after trepanation and temporary restoration. The partially erupted upper right canine (UR3) was undamaged
Dr. Jozef Mincík studied dentistry at the University of Košice in Slovakia, and from 1980 to 1989 assisted in the Department of Conservative Dentistry at the 1st Department of Stomatology Clinic of the Košice University Hospital. He has had his own dental practice in Košice since 1990, and has been head of the Conservative Dentistry section of the Slovakian Dental Association since 2000. His key areas of expertise include esthetic-restorative dentistry, endodontics, and dental traumatology. He is the author of numerous publications and presentations on these subjects.
Dr. Marián Tulenko studied dentistry at the University of Košice and has worked at Dr. Mincík’s practice since 2008. He is a member of the Young Dentists section of the Slovakian Dental Association, and in his publications and presentations he specializes in the areas of esthetic-restorative dentistry, endodontics, and dental traumatology.
Figure 2: Permanent root canal filling of the upper right lateral incisor (UR2). The maxillary central incisors (UR1, UR2) are vital. No resorption is recognizable at the fracture lines
Figure 3: External root resorption of the coronal fragment of the upper left central incisor (UL1) in the fracture line
Figure 4: The permanent endodontic treatment of the upper left central incisor (UL1). External resorption in the fracture line was diagnosed, while the apical region was found to be normal
Figure 5: Considerable healing of the resorption of the fracture gap on the upper left central incisor (UL1) 2 years after endodontic treatment. External resorption of the upper right central incisor (UR1)
Figure 6: The radiograph taken after the root canal filling on the upper right central incisor (UR1)
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Figures 7A-7C: The coronal fragment of the upper right lateral incisor (UR2) is adhesively luted to the apical fragment with the aid of the composite post Rebilda Post (Voco)
Figure 8A: Resection of the apical fragment of the upper right lateral incisor (UR2) and restoration of the bone defect with bone substitute material
Figure 8B: Situation after resection of the upper right lateral incisor (UR2)
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18 Endodontic practice Volume 6 Number 2
CLINICAL
practice, the clinical and radiographic check-ups revealed no pathological changes up to 2008. However, 9 years after the accident, the pulp test on the upper left central incisor (UL1) was negative. The radiograph shows an external inflammatory root resorption of this tooth in the fracture line (Figure 3). Following a temporary calcium hydrox-ide dressing, a permanent restoration was placed in the affected upper left central incisor (UL1). The restoration extended as far as the fracture line because the apical region displayed no changes, and therefore, was most probably vital, as is typical with root fractures (Figure 4). The next check-up was 2 years later. The patient complained of discomfort at the upper right central incisor (UR1). The radiograph showed considerable healing of the external resorption of the fracture gap on the upper left central incisor (UL1); however, on the other hand, we diagnosed external resorption on the upper right central incisor (UR1), similar to the upper left central incisor (UL1) [Figure 5]. The upper right central incisor (UR1) received endodontic treatment similar to the upper left central incisor (UL1). The root canal filling extended as far as the fracture gap (Figure 6). This check-up revealed a periapical process on the upper right lateral incisor (UR2), which was not filled up to the apex
because of an obliteration. In our opinion, the infection extended to the periapex, and therefore to the fracture line via the gingival sulcus. Consequently, we decided to secure both fragments of the tooth with the aid of the glass fiber-reinforced composite post Rebilda Post (Voco) and to seal the gap with composite. In this way, it was possible to save the tooth. We use the fiber-reinforced composite (FRC) Rebilda Post because this system has proven very successful in our experience. One of the benefits of this post is that it has a modulus of elasticity similar to that of the tooth. In this particular case, securing the fragments assists the treatment of the root fracture, and the adhesive luting creates a barrier against ingress of bacteria into the periodontium (Figures 7A-C). Subsequently, we treated the periapical process surgically by performing a resection and retrograde restoration. We restored the bone defect with bone substitute material (Figures 8A and 8B). The latest check-up in June 2011, 12 years after the accident, shows formation of new bone in both fracture lines following the endodontic treatment. Furthermore, the radiograph confirms that the periapical process of the upper right lateral incisor (UR2) has healed following the resection (Figure 9). Thanks to this treatment, the teeth are fully functional in spite of root fractures.
With the exception of the discoloration on the upper right lateral and upper left central incisors (UR2, UL1), the patient has been free of all symptoms for 12 years after the accident (Figures 10 and 11).
ConclusionOur experience confirms that the prognosis for root fractures is very good in most cases. This may be linked to the fact that, in comparison with apical interruption of the blood supply, the revascularization area is large, and the distances to be bridged are small. As mentioned at the beginning, the treatment is determined by the location of the fracture, the nature and degree of dislocation of the coronal fragment, and the stage of root growth.
REfEREncEs
Andreasen JO, Hjorting-Hansen E. Intraalveolar root fractures: radiographic and histologic Study of 50 cases. J Oral Surg. 1967;25:414-426.
von Arx T, Chappuis V, Hänni S. Verletzungen der bleibenden zähne - teil 3: therapie der wurzelfrakturen. Schweiz Monatsschr Zahnmed. 2007;117(2):135-144.
Cvek M, Andreasen JO, Borum MK. Healing of 208 intra-alveolar root fractures in patients aged 7-17 years. Dent Traumatol. 2001;17:53-62.
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Figure 9: The latest check-up in summer 2011: the fracture lines on the maxillary central incisors (UR1, UL2) have become filled with hard tissue. The periapical process of the upper right lateral incisor (UR2) has healed fully
Figure 10: Palatal view of the affected teeth 12 years after the accident
Figure 11: Labial view of the affected teeth 12 years after the accident
This article is part of a series that appears in 10 consecutive issues and
is designed to offer practical advice on some of the most common challenges that we face in endodontics. The purpose is to make the practice of endodontics easier. Some of the information will give you a better understanding of what you are dealing with; some will make it easier to avoid pitfalls; some will show you how to improve the quality of your work; and some will advise what to do in difficult situations. Although each article covers a specific topic, they interrelate, and some of the questions that arise may be answered in other articles. By nature it cannot be comprehensive, otherwise it would be a textbook, but hopefully, it will give you valuable practical information.
Available technologyOne of the primary purposes of root canal treatment is the elimination of bacteria from the root canal system, which as I have described in the first article of this series, is often very complex (Figure 1). When I qualified just over 30 years ago, the practice of endodontics was very different. We relied on 20/20 vision and nothing else. Once the canal entrances had been identified, everything was done pretty much just by feel. Now with the technologies available to us, while the importance of tactile sense cannot be underestimated, it is possible to overcome obstacles that are visible right into the depth of the canals. Magnification in dentistry starts with operating loupes, which will increase the image size from 2x to about 5x (Figure 2). After 5x, the loupes start to become very heavy, and magnification is better provided by the operating microscope,
which magnifies the image from about 5x to 20x (Figure 3). Illumination with the loupes comes in the form of a headlight, which obviates the need for a separate operating light. As it is mounted on the loupe frame or a headband, no shadow is produced. The light source in the operating microscope is integral within the scope itself, so that light passes down the canal walls. In straight canals, the apex can be clearly seen, as well as isthmuses, fins, and secondary canals. Both have their advantages and disadvantages. Loupes are considerably more versatile, and many dental procedures can be carried out at these low magnifications. However one pair of loupes only give one magnification, so the tendency is to have just one pair. Over the years, I have progressed from 2x to 3.25x to 4.25x. There are many situations, particularly in endodontics, where the tooth needs to be seen in much greater detail, and while I do change the magnification from time to time, most of my work is done at 10x. The greater the magnification, the narrower the width of field, and the lower the depth of field. The better we can see what we are doing, the more control
we have. The more control we have, the greater the chances are for a successful result. Not all endodontic procedures require the use of the microscope, but at the very least, it is useful for checking canal cleanliness prior to obturation.
DiagnosisThe microscope has proven itself to be an invaluable tool for confirming the presence of cracks both in the natural crowns of teeth and in the roots of teeth restored with post crowns. External root resorption can also be confirmed with careful examination of the gingival margins under magnification. The marginal fit of restorations and the presence of caries can also be checked (Figure 4).
Canal locationAs discussed in last month’s article, finding the canals can be infinitely more difficult than cleaning and shaping them. The pulp chamber and even the canals themselves may be sclerosed. A very careful technique is required to preserve tooth structure, and this requires a good knowledge of canal anatomy, experience,
Top ten tips: Tip number 6 – Magnification and illumination
20 Endodontic practice Volume 6 Number 2
ENDODONTICS IN FOCUS
Dr. Tony Druttman looks at the importance of magnification and illumination in the practice of endodontics
Figure 1: Complex root canal anatomy in a lower molar tooth
Tony Druttman, MSc, BChD, BSc, has extensive expertise in treating dental root canals, resolving difficult endodontic cases, and saving teeth from being extracted. His two London practices, one in the West End and the other in the City of London, are
restricted to endodontic treatment.www.londonendo.co.uk
Figure 2: Working with magnifying loupes
Figure 3: Working with the operating microscope Figure 4: Caries detected using the microscope
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and the use of the microscope. Second mesiobuccal canals in upper molars can often only be found at high magnification (Figure 5). Other teeth can sometimes have more than the expected number of canals (Figure 6), and failed endodontic treatment is often caused by missed canals. As I have discussed in previous articles in this series, a good quality preoperative radiograph will often indicate the presence of a canal that divides along its length (Figure 7), but the exact position can only be detected by careful visual examination under high magnification (Figures 8A and 8B). Similarly the presence of a second canal in the distal root, or a third canal in the mesial root of a lower molar, can only be detected by careful clinical examination.
Canal preparationBecause of the complexity of the root canal system, canal preparation cannot necessarily be considered to be complete just because a rotary instrument of a certain size and taper has been taken to a predetermined length, even with the accompanying irrigation regimes. The cross-sectional shape of canals may vary along their length. They may be circular at the apex and become oval more coronally, or have a teardrop shape. They may be joined to another canal or another branch via an isthmus, as is often the case with lower incisors and the distal canals of lower molars. C-shaped lower second molars can often present a considerable challenge in preparation. Only careful examination of the
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Figure 7: In tooth 45, the canal divides on the middle third
Figure 8A: Mesiobuccal canal divides in the apical third of the root of upper molar
Figure 8B: Both branches of the canal are clearly seen using the microscope and can therefore be instrumented
Figure 9: Fractured instrument in the MB1 canal viewed under the magnification of the operating microscope
Figure 10A: Fractured spiral filler in the mesial root of a lower molar
Figure 10B: Fractured instrument removed and the tooth retreated
prepared canals using the microscope will identify (some of) those areas of the canal system that have remained unprepared. Seeing around a curve, however, is not an option with the microscope.
Endodontic retreatmentAnother major area of endodontics where the microscope has proved its worth is in endodontic retreatment, both surgical and nonsurgical. The predominant cause of endodontic failure is due to the presence of bacteria, and retreatment involves removing obstructions that prevent access to the site of bacterial contamination. This may involve removing root-filling materials, or bypassing or removing ledges and blockages such as fractured instruments (Figure 9). I will be discussing retreatment in greater detail in the final article of this series. Instruments have been adapted and invented for use in conjunction with the microscope, particularly in the field of ultrasonics. Fractured instruments can often be removed using fine ultrasonic tips to trough around the instrument, removing minimal amounts of dentin (Figures 10A and 10B). This can only be done with the aid of the microscope. This has led to an increase in the success rates of nonsurgical retreatment approaching that of primary treatment. The success rate of surgical endodontics has also increased significantly with the use of microsurgical techniques. Soft tissue management, root end cavity preparation, and suturing techniques have all changed radically since
Figure 11: Common working position leading to musculo-skeletal problems
the introduction of the microscope into surgical endodontics.
ErgonomicsAnother significant benefit from the use of both magnifying loupes and the operating microscope is in the field of ergonomics. The practice of dentistry over many years, especially endodontics, when the operator tends to sit in one position for a considerable length of time, can take its toll on the operator. Back, shoulder, and neck problems are not uncommon because of incorrect posture (Figure 11). By using an increased working distance, operating loupes allow the back to be held straighter than when working without magnification (Figure 12). The microscope allows for the neck, shoulders, and back to be in a comfortable neutral position, especially when used with an operating stool with arm supports (Figure 13). In conclusion, the introduction of increased magnification and improved illumination of the operating field has many benefits, both for the operator and the patient, and nowhere more so than in endodontics. The ability to work with a high level of accuracy and control improves the quality of treatment, reduces treatment time, and reduces operator fatigue. I am convinced that the use of magnification should be an integral part of undergraduate teaching of operative dentistry, particularly in the field of endodontics.
Next issue: Determining length
Figure 12: Improved posture using magnifying loupes
Figure 13: Comfortable neutral posture using the operating microscope
EP
Figure 5: A very small MB2 canal detected after obtura-tion of MB1 due to bubble formation seen with the aid of the microscope
Figure 6: Palatal root has two canals in this upper first molar
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Cone beam computed tomogra-phy (CBCT) Since their discovery in 1895 and first application in dentistry in the same year, X-rays have been an invaluable aid in the practice of dentistry (Cruse, Bellizzi, 1980). Clinicians still depend greatly on dental radiography for obtaining diagnostic information, including the field of endodontics and in relation to the diagnosis of periradicular disease (PRD). One major shortcoming of classic dental radiography, however, is a two-dimensional reproduction of a three-dimensional entity (Patel, et al., 2009). In medicine, this problem was overcome in 1972 by the invention of computed tomography (CT) scanning (Beckmann, 2006). However, due to high radiation exposure, the use of CT scanning in dentistry could not be justified (Patel, et al, 2009). This dilemma has been addressed by the introduction of three-dimensional cone beam CT scanning (CBCT), and since the late 1990s, CBCT scanning has been given serious consideration within maxillofacial diagnostic radiology (Patel, 2009; Farman, et al, 1997).
CBCT versus conventional CTCone beam CT scanning (CBCT), which is also referred to as cone beam volumetric imaging (CBVI) and cone beam volumetric tomography (CBVT), is an extraoral radiographic method of producing three-dimensional digital radiographic information (Patel, et al., 2009; Patel, 2009; Miles, 2008; McNamara, Kapila, 2006; Horner, Drage, Brettle, 2008; Patel, et al., 2007). In conventional CT scanning machines, the X-ray source and detector rotate 360 degrees around the patient at about the rate of 60 times per minute, with a thin fan-shaped beam of X-rays directed through the patient. The thickness of each image slice is determined by the
CBCT within endodontics: an introduction
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CONTINUING EDUCATION
Dr. Navid Saberi presents a guide to cone beam computed tomography
distance the patient is moved through the inside of the CT scanning machine during this synchronized rotation. This creates multiple sectional images that are then processed by a computer to create a three-dimensional image of the patient’s region of interest (Beckmann, 2006, Miles, 2008; Horner, Drage, Brettle, 2008; Patel, et al., 2007). In cone beam CT scanning devices, unlike conventional CT scanning, a narrow cone-shaped beam, as opposed to a fan-shaped beam, rotates between 180 to 360 degrees (depending on the model) around the patient’s region of interest, capturing a volume of the patient, as opposed to a
Navid Saberi, BDS, MFDSRCS(Ed), MSc(Glas), maintains a practice limited to endodontics in London, England. He is also honorary secretary of the Scottish Endodontic Study Group. For more information about that study club, please visit www.sesg.org.uk.
Figure 1: Diagram showing the basic concept of CBCT. CBCT scanner uses a cone beam source to acquire the entire area of interest
Educational aims and objectivesThe purpose of this article is to look at the uses and benefits of using cone beam computed tomography (CBCT) in dentistry.
Expected outcomesCorrectly answering the questions on page 36, worth 2 hours of CE, will demonstrate you understand how using CBCT for endodontic treatment can benefit the clinician and patient.
slice in conventional CT scanners. Cone beam CT scanning also allows the desired image to be produced in a single rotation without the need for moving the scanner or the patient (Figure 1) [Patel, et al, 2009; Patel, 2009; Miles, 2008; Horner, Drage, Brettle, 2008; Patel, et al, 2007; Patel, Kanagasingam, Mannocci, 2010; Cotti, 2010; Scarfe, Farman, 2008]. The X-ray field can also be collimated to include the region of interest only. This quick cone beam production and volumetric image capturing is capable of reducing the exposure by over 50 times in some cases (Patel, 2009; Miles, 2008; McNamara, Kapila, 2006; Horner, Drage,
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Brettle, 2008; Patel, et al., 2007; Patel, Kanagasingam, Mannocci, 2010; Cotti, 2010; Scarfe, Farman, 2008). CBCT is capable of producing high contrast images with good resolution in a short period of time. However, soft tissue contrast is relatively poor in these devices (Horner, Drage, Brettle, 2008; Patel, Kanagasingam, Mannocci, 2010; Scarfe, Farman, 2008). As explained above, the effective dose of CBCT is much less than that for conventional CT, although the dose is dependent on the volume of tissue irradiated, and also the other imaging parameters that are selected (Horner, Drage, Brettle, 2008; Patel, et al., 2007; Scarfe, Farman, 2008). CBCT scanners are also significantly cheaper than conventional CT scanners. A full list of advantages and disadvantages of CBCT and conventional CT can be found in Table 1.
Pixel versus voxelA pixel is a two-dimensional picture element that is a square that measures between 20 and 60 micrometers in size (Miles, 2008; McNamara, Kapila, 2006). A voxel, on the other hand, is a three-dimensional volume element and is a cube, which may or may not be isometric (Patel, 2009; Miles, 2008; McNamara, Kapila, 2006). This is the building block of the volume of the image that has been captured by cone beam CT scanning and then processed and digitized by computer software (Figure 2). The computer software also allows viewing of the image volumes and further image management, manipulation and interactions (Patel, 2009; Miles, 2008; McNamara, Kapila, 2006; Patel, et al., 2007; Patel, Kanagasingam, Mannocci, 2010).
SensorsThe type of sensor determines important image volume characteristics such as the size, shape, and spatial resolution of the reconstructed volume (Patel, 2009; Miles, 2008; McNamara, Kapila, 2006; Patel, et al., 2007; Patel, Kanagasingam, Mannocci, 2010; Scarfe, Farman, 2008). The sensor options include an image intensifier that is coupled to either a charged coupled device (CCD) or complementary metal oxide semiconductor (CMOS), a CCD chip or a thin film transistor (TFT) flat panel type of image receptor (Miles, 2008; McNamara, Kapila, 2006; Scarfe, Farman, 2008). One of the most important sensor characteristics, which determines the
diagnostic superiority of the CBCT machine, is the signal-to-noise or signal-to-glare ratio. This ratio varies between sensors. CCD and flat panel sensors have a higher (better) signal-to-noise ratio than image intensifier systems. This leads to improved diagnostic accuracy when faced with scatter, which is produced by metallic elements and prostheses within the maxillofacial skeleton and teeth. The smaller and more compact size of CCD and flat panel sensors also reduce the overall weight and size of the CBCT unit, and make them more ergonomic. However, the compact CCD sensors produce smaller reconstructed image volumes, and
therefore a smaller anatomic field of view when compared to flat panel and image intensifier sensors. Thereby, they are not suitable for full arch and full maxillofacial skeletal image reconstruction (Patel, 2009; McNamara, Kapila, 2006; Patel, et al, 2007; Scarfe, Farman, 2008). Overall, the image intensifier is an older technology and produces a lower quality of image. The flat panel detectors and CCD sensors are the newest image receptors. These offer less image distortion, wider contrast scale, and glare elimination when compared with the image intensifier receptors (McNamara, Kapila, 2006; Patel, et al., 2007; Scarfe, Farman, 2008).
Figure 2: The concept of a voxel. The volume of images in CBCT is composed of voxels, which can be as small as 0.08 mm3
CBCT Conventional CT
Advantages
• Provides accurate cross-sectional information
• Short scanning time• No superimposed tomographic blurring• Multiplanar views and 3D
reconstruction possible• Uniform magnification• Not technically demanding to perform• Lower dose than conventional CT• PC based software
• Provides accurate cross-sectional information
• Short scanning time• No superimposed tomographic
blurring• Multiplanar views and 3D
reconstruction possible• Uniform magnification• Bone density measurements possible• Soft tissue assessment possible
Disadvantages
• Imaging of entire jaw rather than site of interest in the majority of scanners
• Relatively expensive• Amalgam and metallic restorations can
cause artifacts • Limited bone density information
provided• Not suitable for soft tissue assessment
• Imaging of entire jaw rather than the site of interest
• High dose• Amalgam and metallic restorations
can cause artifacts• Limited availability• Very expensive
Table 1: CBCT versus conventional CT – advantages and disadvantages
Ex vivo trial i-CAT 80 teeth Detection of artificial root # CBCT 20% more accurate than PA
Wenzel et al (2009) Oral Surgery, Oral Medicine, Oral Pathology, Oral Radiology and Endodontology
Ex vivo trial i-CAT 69 teeth Detection of transverse root #CBCT with 0.125 voxel resolution was more accurate than 0.25 voxel or PSP system
Hassan et al (2010) Journal of Endodontics
Ex vivo trial 5 scanners 80 teethDetection of root # by different CBCT scanners
i-CAT was the most accurate
Kamburoğlu et al(2010) Oral Surgery, Oral Medicine, Oral Pathology, Oral Radiology and Endodontology
Ex vivo trialNewTom 3G/
Iluma60 teeth
Accuracy of CBCT (different voxels) and PA in detecting root #
Higher detection of PRD in CBCT cases
Özer (2010) Journal of Endodontics
Ex vivo trial i-CAT 80 teethDetection of root # with different thickness by CBCT and PA
CBCT was determined to be more accurate than PA
Patel and Dawood (2007) International Endodontic Journal
Case report i-CAT 2 teethDiagnosis of external cervical resorption
Sound diagnosis can be made using CBCT
Dudic et al (2009) American Journal of Orthodontics and Dentofacial Orthopaedics
Cross sectional
3D Accuitomo 275 teethCBCT vs. OPG in detecting apical root resorption
CBCT was established to be superior to OPG
Estrela et al (2009) Journal of Endodontics
Cross sectional
i-CAT40 patients(48 scans)
CBCT vs. PA in detecting root resorption
CBCT was 30% more accurate than PA
Liedke et al (2009) Journal of Endodontics
Ex vivo trial i-CAT 60 teethEvaluation of different voxel sizes of CBCT in detecting resorption
CBCT was determined to perform well especially with 0.3mm voxel size
Durack et al (2011) International Endodontic Journal
Ex vivo trial3D Accuitomo
8010 teeth
Diagnostic accuracy of CBCT and PA for the detection of external resorption
CBCT performed much better than PA
La et al (2010) Journal of Endodontics
Case report Implagraphy 1 toothThe use of CBCT in canal identification
Mid-mesial canal in a mandibular first molar was identified using CBCT
dimensional images that can be used for maxillofacial surgical treatment planning, assessing impacted teeth prior to surgical extractions, temporomandibular joint analysis, orthodontics, airway assessment, periodontics, bone level evaluation, implantology, endodontic assessment, diagnosis, and treatment planning.
Clinical applications of cone beam CT scanning within endodonticsCone beam computed tomography (CBCT) has been established to be superior to conventional intraoral and extraoral radiography in diagnostic accuracy. CBCT is capable of producing high contrast images with good resolution in a short period of time. In endodontics, this particularly relates to early diagnosis of periradicular disease
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Quality of reconstructed dataThe quality of reconstructed image formats and data is related primarily to the voxel size, signal-to-noise ratio, and contrast, or dynamic range. Most units these days produce a dynamic range up to 65,536 shades of gray (16 bits). The voxel size ranges from 0.08 to 0.6 mm3. Voxel size is inversely proportional to improved anatomic feature detection. In image intensifier sensors, the reduction of voxel size can only be achieved by reducing the field of view. However, due to low (poor) signal-to-noise ratio in these units, the quality of the reconstructed image cannot be as high quality as CCD and flat panel units. Conversely, flat panel sensors can create a small voxel size for any given field of view (Miles, 2008; McNamara, Kapila, 2006; Patel, et al., 2007; Scarfe,
Farman, 2008). The image data in image intensifier CBCT units can be up to 1.5 gigabytes per scan when using a large field of view. Whereas, the size of the image data in flat panel CBCT units can be up to 400 megabytes, and in CCD, CBCT scanners can reach 100 megabytes. Thus, storage, back-up, and transfer of data in CCD and flat panel CBCT scanners are also easier than in image intensifier CBCT scanners. However, all units require high local and/or regional data transfer network speed and capacity (McNamara, Kapila, 2006; Scarfe, Farman, 2008).
Clinical applications of cone beam CT scanningAdvances in CBCT imaging means these scanners can reconstruct three-
3D Accuitomo 503 obturationsInfluence of obturation length on PRD
CBCT performed better than PA in the detection of PRD and checking obturation length
Matherne et al (2008) Journal of Endodontics
Ex vivo trial i-CAT 72 imagesCBCT vs. CCD vs. PSP in diagnosing root canals
CBCT performed significantly better than intraoral radiography
Michetti et al (2010) Journal of Endodontics
Ex vivo trial Kodak 9000 3D 9 teethAccuracy of CBCT in root canal image reconstruction
CBCT images were similar to real histologic section
Neelakantan et al (2010) Journal of Endodontics
Ex vivo trial 3D Accuitomo 95 teethAccuracy of CBCT in identifying root canals
CBCT was accurate and similar to staining and clearing technique
Huybrechts et al (2009) International Endodontic Journal
Ex vivo trial Accuitomo 2 teethCBCT vs. digital vs. PA in void detection
Digital radiographs performed better than CBCT and PA in detecting small voids
D’Addazio et al (2011) Internal Endodontic Journal
Ex vivo trial i-CAT 16 teeth in 3 mandiblesCBCT vs. PA in diagnosing simulated endodontic complications
Overall CBCT was determined to be superior to PA
Sanfelice et al (2010) Journal of Endodontics
Ex vivo trial i-CAT32 extracted lower first molars
Canal enlargement monitoring using CBCT
Significant differences could be identified pre vs. post instrumentation using CBCT
with greater accuracy of lesion size, extent, nature, and position (Stavropoulos, Wenzel, 2007; Paula-Silva et al., 2009; Patel, et al., 2009; Estrela, et al., 2008). Furthermore, three-dimensional volume of information captured by CBCT can also aid clinicians in the diagnosis of root fractures, root resorption, perforations, obturation voids and defects, and root canal morphology (Naito, Hosokawa, Yokota, 1998; Tyndall, Rathore, 2008; Misch, Yi, Sarment, 2006; Patel, Horner, 2009; Cotton, et al., 2007; Pinsky, et al., 2006; Hassan, et al., 2009; Huybrechts, et al., 2009). Most CBCT studies have either been performed ex vivo on cadavers or on animals. Conclusions drawn from these studies should be carefully analyzed as laboratory tests methodology may not reflect the clinical situation. Furthermore, methods used by authors in CBCT studies should also be critically evaluated in terms of CBCT scanner settings. This is particularly important when two or more machines are being compared as different settings will inherently change the quality of reconstructed three-dimensional images. Unfortunately, this important information is not always provided by the authors. Nevertheless, almost all CBCT studies have shown overwhelming superiority of these imaging machines over conventional radiography (Annex 1). Another benefit of CBCT is its use in evaluation of periradicular healing and endodontic outcome assessment. Paula-Silva, et al., (2009) clearly demonstrated that traditional intraoral radiographic evaluation of periradicular healing is an unsuitable and unreliable method for this purpose. In contrast, CBCT provides acceptable diagnostic information in relation to periradicular repair. However, histological analysis of the root periapex remains the gold standard. In another study, Christiansen, et al., (2009) confirmed that, on average, periapical bone defects measured on periapical radiographs are approximately 10% smaller than on CBCT images. This is a very important finding, and may influence decision making and guidelines regarding conventional radiographic outcome assessment. Current ESE guidelines (2006) state that root canal treatment has an uncertain or an unfavorable outcome if:• Radiographs reveal that a lesion hasremained the same size or has only diminished in size.
• A radiologically visible lesion hasappeared subsequent to treatment, or a pre-existing lesion has increased in size. However, the guideline fails to clarify what constitutes an acceptable radiographic assessment. Now that better diagnostic equipment has become available with CBCT, potentially more cases could be classified as unsuccessful in the future. This is particularly important in endodontic diagnostic radiology and the use of CBCT scanning in outcome assessment of endodontic treatment. In comparison, success and failure assessment criteria for a different treatment modality to endodontic treatment, such as dental implant placement, are generally less strict. The differences between these criteria render the two treatment modalities incomparable. Furthermore, success measures for dental implant longevity and survival have misleadingly led to the common belief that dental implant placement is more successful than endodontic therapy. This belief could negatively influence patient decision making regarding the appropriate treatment. Therefore, radiographic outcome assessment in endodontics should be interpreted with caution (Friedman, Abitbol, Lawrence, 2003) to assist patients and clinicians in making an informed decision in relation to endodontic or dental implant treatment planning. Wu, et al., (2009) argued that a re-duced periapical radiolucency on radiographs does not guarantee that the healing process has begun or is continuing. The authors reported that a high percentage of cases that were confirmed healthy from periapical radiography presented with apical periodontitis in CBCT images. It was recommended that the outcomes of root canal treatment should be re-evaluated in long-term longitudinal studies using CBCT and stricter than normal evaluation criteria. Furthermore, the authors recommended replacement of periapical radiography with CBCT in dental clinics because of the misleading results obtained from periapical radiography. This argument and debate raises a very crucial question – what constitutes endodontic success? The aim of root canal treatment has been to treat periradicular disease. Therefore, the success of root canal treatment will only be achieved by complete resolution of the apical lesion (Ørstavik, Pitt Ford, 2008). However, how should
success be assessed? The gold standard assessment is by means of histological analysis of the root periapex (Simon, et al., 2006; Paula-Silva, et al., 2009). However, performing histological analysis of the apex of every asymptomatic root canal treated tooth is unjustifiable, unrealistic, and difficult to perform. Furthermore, it may cause considerable morbidity, and therefore unethical to carry out. As explained above, success assessment can also be achieved by radiographic monitoring of the lesion. But we now know that conventional radiography is not a reliable method for this assessment. CBCT is shown to be a more accurate diagnostic tool. However, even CBCT is not 100% accurate in the diagnosis of periapical lesions (D’Addazio, et al., 2011). Unfortunately, those authorities who recommend routine assessment of endodontically treated teeth with CBCT fail to mention this fact. So, what is important for clinicians? Consideration should be given to patient-centered outcomes, including patient satisfaction and improved quality of life after root canal treatment as opposed to a paternalistic look at intervention and treat-ment outcome. If we think CBCT is better than periapical radiography, and routine overexposure of patients to radiation is justifiable, why not perform apical surgery in order to obtain a biopsy of every single PRD lesion to establish resolution? After all, histological examination is the proven gold standard and even CBCT cannot match its accuracy. Where do we stop? Dugas, et al., (2002) conducted an interesting study looking at the quality of life and satisfaction outcomes of endodontic treatment. The authors interviewed individuals with known root canal treated teeth, asking them to complete a questionnaire. This questionnaire was an endodontically-adapted quality-of-life instrument consisting of 17 questions. Of the cohort, 97.1% reported satisfaction with the decision to have endodontic treatment. Surprisingly, 96.4% individuals were found to have PRD associated with the root canal treated teeth. The use of quality-of-life instruments and dental satisfaction scales in order to contemporize endodontic assessment was recommended. The authors concluded that further development of endodontic-specific quality of life and satisfaction instruments that measure the impact of endodontic disease, and treatment on
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REfEREnCEs
Beckmann EC. CT scanning the early days. Br J Radiol. 2006;79:5-8.
Christiansen R, Kirkevang LL, Gotfredsen E, Wenzel A. Periapical radiography and cone beam computed tomography for assessment of the periapical bone defect 1 week and 12 months after root-end resection. Dentomaxillofac Radiol. 2009;38(8):531-536.
Cotti E. Advanced techniques for detecting lesions in bone. Dent Clin North Am. 2010;54(2):215-235.
Cotton TP, Geisler TM, Holden DT, Schwartz SA, Schindler WG. Endodontic applications of cone-beam volumetric tomography. J Endod. 2007;33(9):1121-1132.
Cruse WP, Bellizzi R. A historic review of endodontics, 1689-1963, part 2. J Endod. 1980;6(4):532-535.
D’Addazio PS, Campos CN, Özcan M, Teixeira HG, Passoni RM, Carvalho AC. A comparative study between cone-beam computed tomography and periapical radiographs in the diagnosis of simulated endodontic complications. Int Endod J. 2011;44(3):218-224.
Dugas NN, Lawrence HP, Teplitsky P, Friedman S. Quality of life and satisfaction outcomes of endodontic treatment. J Endod. 2002;28(12):819-827.
Estrela C, Bueno MR, Leles CR, Azevedo B, Azevedo JR. Accuracy of cone beam computed tomography and panoramic and periapical radiography for detection of apical periodontitis. J Endod. 2008;34(3):273-279.
European Society of Endodontology. Quality guidelines for endodontic treatment: consensus report of the European Society of Endodontology. Int Endod J. 2006;39(12):921-930.
Farman AG, Ruprecht A, Gibbs SJ, Scarfe WC. Advances in maxillofacial imaging. Amsterdam: Elsevier; 1997.
Friedman S, Abitbol S, Lawrence HP. Treatment outcome in endodontics: the Toronto study. Phase 1: initial treatment. J Endod. 2003;29(12):787-793.
Hassan B, Metska ME, Ozok AR, van der Stelt P, Wesselink PR. Detection of vertical root fractures in endodontically treated teeth by a cone beam computed tomography scan. J Endod. 2009;35(5):719-722. Horner K, Drage N, Brettle D. 21st century imaging. London: Quintessence Publishing Co Inc.; 2008.
Huybrechts B, Bud M, Bergmans L, Lambrechts P, Jacobs R. Void detection in root fillings using intraoral analogue, intraoral digital and cone beam CT images. Int Endod J. 2009;42(8):675-685.
McNamara JA Jr, Kapila SD, eds. Digital radiography and three-dimensional imaging. Monograph 43, Craniofacial Growth Series. Department of Orthodontics and Pediatric Dentistry and Center for Human Growth and Development, The University of Michigan, Ann Arbor: Needham Press; 2006.
Miles DA. Color atlas of cone beam volumetric imaging for dental applications. Hanover Park, IL: Quintessence Publishing Co Inc.; 2008.
Misch KA, Yi ES, Sarment DP. Accuracy of cone beam computed tomography for periodontal defect measurements. J Periodontol. 2006;77(7):1261-1266.
Naito T, Hosokawa R, Yokota M. Three-dimensional alveolar bone morphology analysis using computed tomography. J Periodontol. 1998;69(5):584-589.
Orstavik D, Pitt Ford TR. Essential endodontology. 2nd ed. Oxford, UK: Blackwell Munksgaard; 2008.
Patel S. New dimensions in endodontic imaging: Part 2. Cone beam computed tomography. Int Endod J. 2009;42(6):463-475.
Patel S, Dawood A, Ford TP, Whaites E. The potential applications of cone beam computed tomography in the management of endodontic problems. Int Endod J. 2007;40(10):818-830.
Patel S, Dawood A, Mannocci F, Wilson R, Pitt Ford T. Detection of periapical bone defects in human jaws using cone beam computed tomography and intraoral radiography. Int Endod J. 2009;42(6):507-515.
Patel S, Dawood A, Whaites E, Pitt Ford T. New dimensions in endodontic imaging: part 1. Conventional and alternative radiographic systems. Int Endod J. 2009;42(6):447-462.
Patel S, Horner K. The use of cone beam computed tomography in endodontics. Int Endod J. 2009;42(9):755-756.
Patel S, Kanagasingam S, Mannocci F. Cone beam computed tomography (CBCT) in endodontics. Dent Update. 2010;37(6):373-379.
Garcia de Paula-Silva FW, Hassan B, Bezerra da Silva LA, Leonardo MR, Wu MK. Outcome of root canal treatment in dogs determined by periapical radiography and cone-beam computed tomography scans. J Endod. 2009;35(5):723-726.
de Paula-Silva FW, Santamaria M Jr, Leonardo MR, Consolaro A, da Silva LA. Cone-beam computerized tomographic, radiographic, and histologic evaluation of periapical repair in dogs’ post-endodontic treatment. Oral Surg Oral Med Oral Pathol Oral Radiol Endod. 2009;108(5):796-805.
de Paula-Silva FW, Wu MK, Leonardo MR, da Silva LA, Wesselink PR. Accuracy of periapical radiography and cone-beam computed tomography scans in diagnosing apical periodontitis using histopathological findings as a gold standard. J Endod. 2009;35(7):1009-1012.
Pinsky HM, Dyda S, Pinsky RW, Misch KA, Sarment DP. Accuracy of three-dimensional measurements using cone-beam CT. Dentomaxillofac Radiol. 2006;35(6):410-416.
Scarfe WC, Farman AG. What is cone-beam CT and how does it work? Dent Clin North Am. 2008;52(4):707-730.
Simon JH, Enciso R, Malfaz JM, Roges R, Bailey-Perry M, Patel A. Differential diagnosis of large periapical lesions using cone-beam computed tomography measurements and biopsy. J Endod. 2006;32(9):833-837.
Stavropoulos A, Wenzel A. Accuracy of cone beam dental CT, intraoral digital and conventional film radiography for the detection of periapical lesions. An ex vivo study in pig jaws. Clin Oral Investig. 2007;11(1):101-106.
Tyndall DA, Rathore S. Cone-beam CT diagnostic applications: caries, periodontal bone assessment, and endodontic applications. Dent Clin North Am. 2008;52(4):825-841.
Wu MK, Shemesh H, Wesselink PR. Limitations of previously published systematic reviews evaluating the outcome of endodontic treatment. Int Endod J. 2009;42(8):656-666.
patients’ well being should take place. This new way of treatment evaluation will help put patient-based outcomes at the center of endodontic treatment assessment. Clinical endodontics has been defined as the prevention and/or elimination of periradicular disease (Ørstavik, Pitt Ford, 2008). This definition must be revised due to the unreliability of diagnostic equipment available to us. Clinical endodontic outcomes should be more patient focused and concentrate more on the elimination of the clinical signs and symptoms of periradicular disease. Indeed, even periradicular disease may not always be the primary factor in determining the outcome of root canal treatment. Moreover, the term success should perhaps be replaced
by the term survival or functionality. This is especially important when direct comparison between endodontics and dental implant survival rates is being made. Furthermore, this will reduce patients being confused and misled over often reported higher survival rates of implants. ConclusionCBCT has been established to be superior to conventional intraoral and panoramic radiography in its accuracy and sensitivity in detecting endodontic related pathology. The use of CBCT significantly enhances the clinician’s ability to diagnose PRD and other endodontic complications, particularly when compared with conventional intraoral radiography. Therefore, more endodontic
disease may be detected in the future. However, strict selection criteria for CBCT use must be followed, and routine CBCT examination of patients should be avoided. This will reduce unnecessary patient exposure to radiation, especially when the question for which radiographic exposure is required can often be answered by lower-dose conventional intraoral radiography. In addition, routine post root canal treatment radiographic follow-up by means of CBCT in patients without clinical signs or symptoms of endodontic disease is not recommended. EP
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IntroductionThe main objective of endodontic treatment is to obtain complete debridement of infected tissues from the root canal complex, and to prepare the system to meet biological and mechanical requirements. The second objective is to protect the original design of the root canal system, and to preserve the size, shape, and position of the apical foramen (Schilder, 1974). Cleaning and shaping of long, thin, and curved root canals challenge the clinician’s endodontic skills (Mandell, et al., 1999; Haïkel, et al., 1999). These difficulties predispose to instrument fracture, ledging, and blockages resulting from insufficient irrigation, and may result in dentinal mud, root perforations, apical zipping, elbowing, strip perforations, and accidental extrusion of debris. Civjan, Huget, and DeSimon (1975), initiated the use of nickel-titanium in dentistry. The nickel-titanium alloy is super elastic and can return, within considerable limits, to its original shape. Once the material is stretched, however, certain changes can take place within the austenitic structure. A martensitic transformation ensues and, if the instrument is stretched beyond its elastic limit, the structure will rupture and lead to instrument failure. Fracture of an endodontic instrument inside the root canal remains a serious problem and can alter the prognosis (Mandell, et al., 1999; Haïkel, et al., 1999), impeding the likelihood of reaching the final goal of the planned treatment (Schilder, 1967). With continuous rotation inside the root canal, the file encounters torsional and bending stress, which causes intense
New instruments for root canal negotiation and preparation
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Drs. Peet van der Vyver and Casper Jonker introduce X-plorer canal navigation nickel-titanuim files for glide path preparation followed by Typhoon Infinite Flex nickel-titanium files for root canal preparation
compression and flexion forces within the file. This can lead to structural fatigue and fracture (Yum, et al., 2011; Zuolo, Walton, 1997). Torsional stress can be described as the amount of stress generated within the instrument when it engages the root canal wall or when the operator subjects the instrument to increased apical force. This is the main cause of instrument fracture. Bending stress can be described as the force generated within the nickel-titanium alloy by rotating an instrument in a
Dr. Peet J. van der Vyver is professor at the Department of Odontology, School of Dentistry, University of Pretoria and Private Practice, Sandton, South Africa.
Dr. Casper Jonker is senior lecturer at the Department of Odontology, School of Dentistry, University of Pretoria, South Africa.
Educational aims and objectivesThe purpose of this article is to discuss root canal negotiation and preparation with specific types of files.
Expected outcomesCorrectly answering the questions on page 36, worth 2 hours of CE, will demonstrate that you can:•Identify certain challenges to endodontic treatment.•Realize some advantages of the nickel-titanium alloy.•Become familiar with X-plorer and Typhoon Infinite Flex nickel-titanium files.
curved root canal. This will result in repeated compression and flexing at the point of maximum curvature — a very destructive form of loading of the instrument, despite the fact that nickel-titanium has superior elasticity and that there is no binding to the canal wall (Pruett, Clement, Carnes, 1997). Bending stress is a very important factor affecting fatigue within the nickel-titanium file, and it may be an unexpected problem if the root canal anatomy is unknown. A factor that could greatly influence the failure rate of nickel-titanium endodontic
files is the initial use of stainless steel files in the creation of a “glide path” before the first rotary instrument is introduced into the root canal (Berutti, et al., 2004; Patiño, et al., 2005). A glide path is a smooth passage that extends from the canal orifice in the pulp chamber to its opening at the apex of the root (West, 2006). This should, in theory, provide a continuous, uninterrupted pathway for the rotary nickel-titanium instrument to enter and to move freely to the root canal terminus. The main purpose of a glide path is to create a root canal diameter the same size as, or ideally a size bigger than, the first rotary instrument introduced (Berutti, et al., 2007). Various methods have been advocated to create a glide path. Several authors use stainless steel K-Files (Berutti, 2004; Walsch, 2004; Mounce, 2005), and others recommend the use of a reciprocating handpiece (Kinsey, Mounce, 2005; van der Vyver, 2011). The most recent development in glide path preparation is to use stainless steel handfiles in combination with rotary nickel-titanium instruments, e.g., PathFile™ (Dentsply/Maillefer), G-Files™ (Micro-Mega), EndoWave MGP Mechanical Glide Path kit (J Morita), Scout-RaCe files (FKG Dentaire, La Chaux-de-Fonds, Switzerland), RaCe ISO 10 (FKG, Dentaire,) and X-plorer canal navigation nickel-titanium files (Clinician’s Choice Dental Products Inc). The purpose of this article is to introduce X-plorer canal navigation nickel-titanium files that can be used for glide path preparation followed by Typhoon™ Infinite Flex nickel-titanium files (Clinician’s Choice Dental Products Inc.) that can be used for root canal preparation.
X-plorer canal navigation nickel-titanium files This is the most recent system that can be used for glide path enlargement after initial negotiation and establishment of a glide path with a No. 10 K-File by hand. The system consists of three rotary nickel-titanium instruments that are characterized by a 10 mm fluted cutting zone on each instrument. The advantage of the short cutting flute area on the files ensures that less of the file is engaged during glide path enlargement, resulting in less stress on the files with a reduced incidence of breakage (Sides, 2012). All three instruments can be used at 400 rpm. The first X-plorer instrument (white ring, marked 01) [Figure 1] has an ISO 15 tip
size with a constant taper of 1%. It must be noted that this is the smallest endodontic nickel file on the market since traditional stainless steel hand instruments and most rotary nickel-titanium glide path instruments have a taper of 2%. This instrument has a triangular cross section that provides this tiny instrument with excellent flexibility and potential to negotiate complex root canal anatomy transforming the canal diameter from a size ISO 10 to size ISO 15. The second X-plorer instrument (yellow ring, marked 01) [Figure 2] has an ISO 20 tip size with a constant taper of 1%. This instrument has a square cross section to provide the 10 mm of cutting flutes with more strength as it enlarges the glide path to a size 20. The last instrument in this series (yellow ring, marked 02) [Figure 3] has an ISO 20 tip size with a constant taper of 2%. This instrument also has a square cross section for added strength when it enlarges the glide path with more taper.
endodontic files are manufactured using controlled-memory (CM) nickel-titanium wire. Shen, et al., (2011) demonstrated that CM-Wire was 300% to 800% more resistant to fatigue failure than conventional nickel-titanium. These authors also noted that the instruments showed many more crack origins than did conventional instruments, but the increased fatigue resistance can be ascribed to CM-Wire’s bulk mechanical properties and increased fatigue crack thresholds. A major advantage of the Typhoon CM file is that its memory has either been removed or controlled by a special thermomechanical process. This remarkable product differs from any
other nickel-titanium rotary endodontic instrument because the instrument can be pre-curved (Figure 4) and bent to adapt to root canal curvature. This feature allows the instrument to follow the root canal anatomy without creating unwanted, disproportionate lateral forces on the canal walls. Precurving of the instrument also facilitates working on teeth with limited access (second and third molars) and allows management of root canals with ledges (Sides, 2012). The Typhoon CM file has increased torsional strength and increased resistance to cyclic fatigue and is more likely to unwind than separate. The instrument “follows” the root canal, preserving tooth structure as less is removed during cleaning and shaping (Sides, 2012). Traditional nickel-titanium instruments have perfect memory, which causes straightening of the root canal curvature (Sides, 2012). The Typhoon CM instrument will not attempt to straighten in-curved root canals, and hence should not alter original root canal anatomy. The files are available in sizes ISO 20-45 with a .04 taper and sizes ISO 20-35 with a .06 taper (Figure 5). All the instruments
have a triangular cross section, variable pitch and helical angle, and a non-cutting tip. The manufacturer recommends that the crown-down technique should be used after glide path establishment.
Clinical considerations and instrument sequence The clinical considerations and instrument sequence when using X-plorer navigation nickel-titianim instruments are as follows:
1. Prepare an access cavity that will ensure straightline access into all the root canalsFigure 6 depicts a clinical case where a dentist prepared an incorrect access
cavity on an maxillary upper fisrt molar. Because of the lack of straightline access into the root canal system, a size 10 K-File fractured in the mesiobuccal canal during the initial negotiation of the root canal (Figure 7). Figure 8 illustrates the outline of the access cavity after removal of the temporary restorative material.
2. Remove any coronal interference, eliminating any obstruction or accentuated curvatures in the coronal third of the root canalFigure 9 shows the modified access cavity preparation. Under magnification, it was noted that the pulp chamber and the canal orifices was obstructed with a large attached pulp stone. A Start X™ tip No. 3 (Dentsply/Maillefer) was used to remove the pulp stone from the pulp chamber
34 Endodontic practice Volume 6 Number 2
CONTINUING EDUCATION
(Figure 10). Four root canals were located. An X-Gates (Dentsply/Maillefer) was used to remove more restrictive dentin at the canal orifices, allowing more direct access into the four root canals (Figure 11).
3. Negotiate the root canals up to working length (established with apex locator or radiograph) and establish patency with a pre-curved stainless steel K-File (size 06, 08)A pre-curved size 06 C+ file (Dentsply/Maillefer) was used to bypass the fractured instrument in the mesiobuccal root canal. Figure 10 shows the length determination radiograph after all the canals were negotiated to full working length.
4. Glide path preparation with size 08 K-File and X-plorer navigation nickel-
titanium instruments • Do not proceedwith the X-plorer files
before an initial glide path has been established up to a size 08 K-File. To verify this, a size 08 K-File must be placed at working length, withdrawn 1.5 mm by hand from the root canal, and pushed back to working length without any difficulty. The above procedure is then repeated, but the file is respectively withdrawn up to 3 mm and 5 mm from the root canal. When the file can travel 5 mm from working length up to the established working length in the root canal, a successful glide path has been established.
• X-plorer file No. 1 (15/01mm) [Figure1] is introduced into the root canal at a rotation speed of 400 rpm in a delicate in and out movement until working
Figure 6: Incorrect access cavity on a maxillary upper first molar
Figure 7: Radiograph showing a fractured instrument in the mesiobuccal root canal
Figure 8: Outline of the incorrect access cavity on a maxillary upper first molar after removal of the temporary restorative material
Figure 9: Modified access cavity preparation. Note the evidence of an attached pulp stone
Figure 10: Access cavity after removal of the attached pulp stone, exposing the canal orifices on the pulp floor
Figure 11: Final access cavity preparation showing the canal orifices of the mesiobuccal 1 and 2, distobuccal and palatal canals after restrictive dentin was removed with an X-Gates (Dentsply/Maillefer)
length is reached (3-5 seconds). The instrument is then removed from the canal. It is important to note that X-plorer files must not be kept rotating in a stationary position in the root canal, especially in severely curved root canals due to the increase in metal fatigue on the instrument.
• Irrigation after each X-plorer file isrecommended to remove dislodged debris from the root canal. In canals that demonstrate accentuated curves in the apical third of the root canal system, it is also recommended by the authors to recapitulate with the size 08 K-File by hand to ensure complete patency of the root canal.
• X-plorerfileNo.2 (20/01) [Figure2] isthen introduced followed by X-plorer
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Volume 6 Number 2 Endodontic practice 35
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Berutti E, Cantatore G, Castellucci A, Chiandussi G, Pera F, Migliaretti G, Pasqualini D. Use of nickel titanium rotary Pathfile to create the glide path: comparison with manual preflaring in simulated root canals. J Endod. 2009;35:408-12.
Berutti E, Negro AR, Lendini M, Pasqualini. Influence of manual preflaring and torque on the failure rate of Protaper rotary instruments. J Endod. 2004;30:228-30.
Civjan S, Huget EF, DeSimon LB. Potential applications of certain nickel-titanium (Nitinol) alloys. J Dent Res. 1975;54:89-96.
Di Fiore PM, Genov KI, Komaroff E, Dasanayake AP, Lin L. Fracture of ProFile nickel-titanium rotary instruments: a laboratory simulation assessment. Int Endod J 2006;39:502-9.
Haïkel Y, Serfaty R, Bateman G, Senger B, Allemann C. Dynamic and cyclic fatigue of engine-driven rotary nickel-titanium endodontic instruments. J Endod. 1999;25(6):434-40.
Kinsey B, Mounce R. Safe and efficient use of theM4 safety handpiece in endodontics. Roots. 2008;4:36-40.
Mandel E, Adib-Yazdi M, Benhamou LM, Lachkar T, Mesgouez C, Sobel M. Rotary Ni-Ti ProFile systems for preparing curved canals in resin blocks: influence of operator on instrument breakage. Int Endod J. 1999;32:436-43.
Mounce R. Endodontic K-Files: invaluable endangered species or ready for the Smithsonian? Dentistry Today. 2005;24(7):102-4.
Pruett JP, Clement DJ, Carnes DL Jr. Cyclic fatigue testing of nickel-titanium endodontic instruments. J Endod. 1997;23:77-85.
Schilder H. Filling root canals in three dimensions. Dent Clin North Am. 1967;11:723-44.
Schilder H. Cleaning and shaping the root canal. Dent Clin North Am. 1974;18:269-96.
Shen Y, Qian W, Abtin H, Gao Y, Haapasalo M. Fatigue testing of controlled memory wire nickel-titanium rotary instruments. J Endod. 2011;37:997-1001.
Sides E. Keep your eye on the prize: predictable root canal shaping with the restored tooth in mind. Oral Health. 2012;87-93.
Van der Vyver PJ. Creating a glide path for rotary NiTi instruments: part one. Endod Practice. 2011;14(1):40-3.
Patiño PV, Biedma BM, Liébana CR, Cantatore G, Bahillo JG. The influence of a manual glide path on the separation rate of Ni-Ti rotary instruments. J Endod 2005;31:114-6.
West J. Endodontic update. J Esthet Restor Dent. 2006;18:280-300.
Walsch H. The hybrid concept of nickel-titanium rotary instrumentation. Dent Clin North Am. 2004;48:183-202.
Yum J, Cheung GS, Park JK, Hur B, Kim HC. Torsional strength and toughness of nickel-titanium rotary files. J Endod. 2011;37:382-6.
Zuolo ML, Walton RE. Instrument deterioration with usage: nickel titanium versus stainless steel. Quintessence Int. 1997;28: 397-402.
Figure 12: Length determination radiograph Figure 13: Final result after obturation
file No. 3 (20/02) [Figure 3] following the same protocol as described above.
5. Root canal preparation with Typhoon Infinite Flex nickel-titanium instruments • It isrecommendedbytheauthorsthat
the coronal third of the root canals are prepared with a Typhoon 35/06 taper file, followed by 30/04, 25/06 and 20/04 using the crown down technique, until the full working length of each root canal is reached. After each file sequence, it is advisable to irrigate with sodium hypochlorite and to reestablish patency with a size 08 or 10 K-File. Final apical preparation can be done with the 25/06 or 30/04 depending on the size of the root canal.
Figure 13 demonstrates the final result
of the clinical case after the four root canals were prepared with Typhoon Infinite Flex nickel-titanium instruments according to the above mentioned technique. Obturation was done with gutta-percha cones and Pulp Canal Sealer™ (SybronEndo) using the Calamus® Dual Obturating Unit (Dentsply/Maillefer).
ConclusionsThe development of endodontic instruments has reached new levels in the last few years. Unfortunately, instrument fracture still remains a major concern for all clinicians performing endodontic treatment, and the CM wire was developed in an attempt to avoid instrument fatigue and failure. The fact remains that clinicians need to respect the limitations of each instrument and to carefully follow the manufacturer’s instructions for the cleaning and shaping sequence. Clinical assessment studies and published research show that when operators take the necessary precautions and follow the prescribed instructions regarding the use of the particular endodontic system, the risk of instrument fracture can be as low as four cases per 1,000 (Di Fiore, 2006). EP
1. Cleaning and shaping of ________root canals challenge the clinician’s endodontic skills.a. longb. thinc. curvedd. all of the above
2. Civjan, Huget, and DeSimon (1975) initiated the use of _______ in dentistry.a. nickel-titaniumb. stainless steelc. gutta perchad. chromium
3. The nickel-titanium alloy is ______and can return, within considerable limits, to its original shape.a. precurvedb. super elasticc. rigidd. prone to ledging
4. _______ can be described as the amount of stress generated within the instrument when it engages the root canal wall or when the operator subjects the instrument to increased apical force.a. Bending stressb. Martensitic transformationc. Torsional stressd. Flexion forces
5. _______can be described as the force generated within the nickel-titanium alloy by rotating an instrument in a curved root canal.a. Bending stressb. Torsional stressc. Cyclic fatigued. Restrictive fatigue
6. A _____ is a smooth passage that extends from the canal orifice in the pulp
chamber to its opening at the apex of the root. a. cutting fluteb. pulp chamberc. glide pathd. pulp stone
7. The main purpose of a glide path is to create a root canal diameter_________ the first rotary instrument introduced.a. several sizes larger than b. the same size asc. ideally a size bigger thand. both b and c
8. Shen, et al., (2011) demonstrated that CM-Wire was _______more resistant to fatigue failure than conventional nickel- titanium.a. 50% to 75%b. 100% to 150%c. 200% to 250%d. 300% to 800%
9. A major advantage of the Typhoon CM file is that its memory has either been removed or controlled by a special _______ process.a. extrusionb. thermomechanicalc. tortional d. rotary
10. Clinical assessment studies and published research show that when operators take the necessary precautions and follow the prescribed instructions regarding the use of the particular endodontic system, the risk of instrument fracture can be as low as ______.a. four cases per 500b. four cases per 1,000c. five cases per 1,200d. three cases per 750
New instruments for root canal negotiation and preparation
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36 Endodontic practice Volume 6 Number 2
ENDODONTIC PRACTICE CEC
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CBCT within endodontics: an introductionSABERI
1. In conventional CT scanning machines, the X-ray source and detector rotate 360 degrees around the patient at about the rate of 60 times per minute, with a thin ______ beam of X-rays directed through the patient. a. fan-shapedb. cone-shapedc. sphericald. straight
2. Cone beam CT scanning also allows the desired image to be produced in ______ without the need for moving the scanner or the patient.a. a single rotationb. two rotationsc. three rotationsd. four rotations
3. The X-ray field can also be ______ to include the region of interest only (to reduce radiation exposure).a. slicedb. contrastedc. collimatedd. superimposed
4. As explained above, the effective dose of CBCT is _____ that for conventional CT, although the dose is dependent on the volume of tissue irradiated, and also the other imaging parameters that are selected.a. much more thanb. much less thanc. in the same range asd. exactly equal to
5. A pixel is a two-dimensional picture element that is _____ that measures between 20 and 60 micrometers in size.a. cone-shapedb. fan-shapedc. spherically-shaped
d. a square
6. A voxel, on the other hand, is a three-dimensional volume element and is a _____, which may or may not be isometric.a. wave-shapeb. spherec. cubed. rectangle
7. The type of sensor determines important image volume characteristics such as the _____of the reconstructed volume. a. sizeb. shapec. spatial resolutiond. all of the above
8. CBCT is capable of producing ______ images with good resolution in a short period of time.a. two-dimensionalb. pixilatedc. high contrastd. none of the above
9. In endodontics, this particularly relates to early diagnosis of periradicular disease with greater accuracy of lesion _______, and position.a. sizeb. extentc. natured. all of the above
10. CBCT has been established to be superior to ______ in its accuracy and sensitivity in detecting endodontic related pathology.a. conventional intraoralb. intraoral photographsc. panoramic radiographyd. both a and c
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Preoperative risk assessment is essential in endodontics. It includes visualizing
the final result, developing operative strategies to avoid clinical misadventure, and optimizing cleaning and shaping. This should be contrasted with an unplanned procedure in which clinicians rapidly find themselves with any one of a number of possibly irreparable iatrogenic challenges. This article was written to discuss the preoperative risk assessment and treatment planning of a complex case. While not intended to be a comprehensive guide to risk assessment, this article discusses many common clinical challenges (Figures 1A and 1B).
Goal of endodontic therapy As a starting place, it has value to revisit the goals of endodontic therapy and the principles of canal preparation. The goal of endodontic therapy is the three-dimensional cleaning, shaping, and obturation of the canal system, and placement of a post endodontic coronal seal with the goal of tooth retention to full esthetic and functional capabilities. The endodontic versus extraction/implant clinical decision-making process is in large measure an assessment of the greatest patient benefit relative to the risks, costs, and probabilities of treatment success. These goals and principles of canal preparation are to: 1) Maintain the original position of the
canal2) Maintain the original position and size of
the apical foramen3) Prepare a tapering funnel with narrowing
cross-sectional diameters; in essence, mimic the shape of a tornado
4) Prepare a taper proportional to the external dimensions of the root that does not predispose the root to subsequent vertical root fracture
5) Prepare a taper allowing cone fit with tug back and ideal obturation hydraulics during down pack with warm vertical obturation techniques (and warm techniques of all types)
6) Prepare a taper optimizing the necessary volume and space for activation of endodontic irrigants
Extraction cures endodontic disease because the entire pulp is taken out of the patient. To the degree possible, the endodontic procedure mimics extraction and removes as much pulp as possible from the patient; thus, clinical success increases. Iatrogenic events and compromises in cleaning and shaping prevent these goals, and diminish the prospects for clinical success.
The clinical caseThe patient was a 72-year-old female whose medical history was noncontributory to the clinical narrative. Periapical radiographic pathology was observed on tooth No.19, and the patient was referred for endodontic treatment on tooth No. 19 by her general dentist. The tooth was asymptomatic. Tooth No.19 had a previous access attempted approximately 7 years previously without canal location. The tooth was
crowned. Percussion, palpation, mobility, and probings on tooth No.19 were all within normal limits. Thermal testing to cold revealed no response. Radiographically, previous access was visible near below the pulp chamber toward the distal. The mesial root had moderate curvature and visible calcification of both roots. The distal root apex showed mild blunting, which could be interpreted as external root resorption. The apex of the distal root, despite the coronal calcification, was anticipated to possibly lack a minor constriction as a result. A diagnosis of non-vital pulp was made. Informed consent for endodontic treatment was obtained and treatment completed as described. Preoperative risk assessment revealed several potential iatrogenic issues. The strategies undertaken to avoid these possible outcomes are also addressed.
1) Canal location might prove impossible or lead to significant loss of cervical tooth structure. While this outcome is possible, with a surgical operating microscope (Global Surgical, Zeiss), it was reasonably expected that the canals could be located without furcal perforation, because they are radiographically visible. Even if the canals had not been visible, an attempt at treatment would still have been made as, in the author’s opinion, the absence of a visible canal is only a clue as to the degree of calcification, not the absolute negotiability of the canal.
It was decided to remove the crown before any attempt at canal location to
Preoperative risk assessment and endodontic treatment planning: examination of a complex clinical endodontic case
38 Endodontic practice Volume 6 Number 2
CASE STUDY
Dr. Rich Mounce looks at some common challenges in endodontic therapy
Figures 1A and1B: The clinical case described. Preoperative and postoperative views
Dr. Rich Mounce is in full-time endodontic practice in Rapid City, South Dakota. He has lectured and written globally in the specialty. He owns MounceEndo, LLC, marketing the rotary nickel-titanium MounceFile in
Controlled Memory and Standard NiTi. Dr. Mounce can be reached at [email protected]: @MounceEndo
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40 Endodontic practice Volume 6 Number 2
CASE STUDY
optimize visualization and tactile control over both the orifice and the instruments used to attempt negotiation. In this clinical situation, attempting to preserve the crown would impede canal location to one degree or another.
2) Given the curvature and calcification of the mesial root, rotary nickel-titanium (RNT) file separation is a risk.
Several types of separation could be anticipated if the root anatomy was not negotiated or shaped correctly. While any one of a number of locations and failure mechanisms are possible, torque failure is a risk in the coronal third or at the point of greatest curvature in the middle third of the mesial root. Cyclic fatigue RNT failure in the apical third of the root is also a concern. Several strategies to avoid RNT file separation were employed (discussed below). Emphasis in treatment was placed on obtaining patency, creation of a reproducible glide path, and using a step-back method with the chosen RNT file system (MounceFiles Controlled Memory Assorted Pack).
3) Once the canals are located, it is critical that the coronal third shape is proportional to the external root form and shaped tapering funnel with narrowing cross-sectional diameters; in essence, it should resemble a tornado. Gross overflaring of the coronal and middle thirds carries significant iatrogenic risk (of long-term vertical fracture, perforation, and adequate irrigation due to a lack of continuous taper among other issues).
Prior to starting treatment, from orifice to apex, it was decided the mesial root would have a final taper of .06 and an orifice opener of no greater than .08 taper (MounceFile, .08/25 Controlled Memory RNT) would be inserted to the point of first curvature. Choosing a taper prior to initiating treatment guides the selection of orifice openers and minimizes the risk of over-enlarging the orifice, transporting the canal, orifice blockage, weakening the root, and/or causing a perforation.
4) Given the shape of the radiolucency at the apex of the distal root, the root needed careful inspection for possible vertical fracture.
It is uncommon to have a tooth vertically fracture without a post and without previous endodontic therapy. Regardless, it was imperative to visually rule out vertical root fracture once the access was established. If a fracture line were visible below the level of the furcal
floor from the distal axial wall, the tooth would require extraction.
5) Aggressive shaping using the wrong instruments and sequence made canal transportation and blockage a risk at multiple levels of the canal (especially at the junction of the middle and apical third of the mesial root, the apex of the distal root, and the orifices of both mesial and distal canals).
Once the canal orifices were located, proper initial management was essential to avoid blockage. The clinician must be mindful that blockage and transportation can easily occur at any level of a canal (taking into account the anatomy present) if incorrectly sized instruments (too tapered and/or excessive tip size) are used too forcefully in the wrong sequence, especially without adequate irrigation and recapitulation. The exact sequence of hand files used and the rationale for each follows in the technique description below.
6) It was not clear from the radiographs if the distal root apex had mild external root resorption.
If external root resorption is present, despite the coronal calcification, transportation of the distal root apex is a risk if working length is not carefully determined, and the minor constriction respected and left in its original position and at its original size.
7) Treating the tooth in one visit risks post-endodontic pain and swelling.
Clinical opinions vary, and the literature is not conclusive as to the appropriateness of one versus two-visit treatment in non-vital teeth. Prior to starting the case, it was decided if the canals were clean and dry at the time of cone fit, after optimal cleaning, shaping and irrigation, the case would be treated in one visit; otherwise the tooth was planned for two-visit treatment with calcium hydroxide.
The clinical treatmentPrior to initiating treatment, informed consent was obtained. Informed consent for this patient included a discussion of the potential challenges listed above. The patient was prepared via the informed consent for two-visit treatment if necessary. All treatment took place under the surgical operating microscope. The crown was removed in addition to the composite from the previous access attempt. The mesial canals were not easily located initially, but the distal was relatively easily found.
The first hand file used to initiate canal negotiation was carefully chosen. Taking an orifice opener (Gates Glidden or RNT) into the mesial root orifices without hand file exploration risked canal blockage. The first file into the mesial orifices was the Mani #6 K file. This file was chosen for its flexibility and tip diameter. The estimated working length, determined from the preoperative
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1) Shen Y, Qian W, Abtin H, Gao Y, Haapasalo M. Fatigue testing of controlled memory wire nickel-titanium rotary instruments. J Endod. 2011;37(7):997–1001.
2) Shen Y, Qian W, Abtin H, Gao Y, Haapasalo M. Effect of environment on fatigue failure of controlled memory wire nickel-titanium rotary instruments. J Endod. 2012;38(3):376-80.
3) Shen Y, Zhou HM, Zheng YF, Campbell L, Peng B, Haapasalo M. Metallurgical characterization of controlled memory wire nickel-titanium rotary instruments. J Endod. 2011;37(11):1566-1571.
4) Zhou HM, Shen Y, Zheng W, Li L, Zheng YF, Haapasalo M. Mechanical properties of controlled memory and superelastic nickel-titanium wires used in the manufacture of rotary endodontic instruments. J Endod. 2012;38(11):1535-1540.
5) Ninan E, Berzins DW. Torsion and bending properties of shape memory and superelastic nickel-titanium rotary instruments. J Endod. 2013;39(1):101-104.
radiographs, was 21 mm. After multiple insertions of numerous Mani #6 K-Files, this file was able to reach the estimated working length and an electronic working length taken (Elements Diagnostic Unit, SybronEndo). The Mani #6 (Endo Tech) stainless steel hand K-File was tightly bound in both canals when it reached the mesial root apex. The file was reciprocated with the W&H Synea WA-62A reciprocating handpiece until it would move freely. The Mani #8 D finder, a file designed to locate and negotiate calcified canals, followed the #6 Mani K-File. The D finder is much stiffer than a K-File and holds its shape upon introduction into a calcified canal much better than its K-File equivalent. The #8 Mani D finder was used manually until it moved freely in all canals. Subsequently, the Mani #10 and #15 SEC O K-File (safe ended K-File) were reciprocated with the reciprocating handpiece attachment listed above to create the glide path. In a similar fashion, Mani #6 and #8 K-Files were initially introduced into the distal canal to the estimated working length (22 mm). The distal canals were similarly reciprocated with the Mani #10 and #15 SEC O K-File to prepare the glide path. For both roots, the estimated working length and the true working lengths were essentially equivalent. When the #15 Mani SEC O K-File spun freely at the total working length (TWL), the
Figure 3: The MounceFile Assorted Pack (.08/25, .06/25, .04/25, .03/25, .02/25, .03/30 from left to right)
canals were enlarged with the MounceFile Controlled Memory Assorted Pack. The pack contains .03/30, .02/25, .03/25, .04/25, .06/25, and .08/25 instruments. Controlled Memory RNT files are created by a proprietary thermomechancial process, which results in a RNT file that retains its shape if curved. As a result, the RNT file is curved as it rotates around the canal curvature. This stands in contradiction to the super elasticity of standard nickel-titanium files1-5(Figures 2A-2E). The MounceFiles were introduced in a step-back manner, with the .02/25 followed by the .03/25, .04/25, .06/25, and .08/25 instruments used in succession. Files were introduced as many times as needed to reach the apex and provide a final taper of .06 from orifice to apex and .08 taper to the point of first canal curvature. Irrigation and recapitulation followed each instrument insertion. The .03/30 instrument was used last in order to prepare the master apical diameter (Figure 3). After shaping procedures, the canals were irrigated using ultrasonic technique, and upon drying, a .06/25 gutta-percha cone was trimmed and fit to the true working length using EndoRez® sealer (Ultradent Products, Inc.). Obturation was performed with the vertical compaction technique using EndoRez sealer. (Elements Obturation Unit™, SybronEndo). Composite was placed in the access and the patient referred back to her general
Figures 5A and 5B: Clinical case retreated with the MounceFile SNT Assorted pack (.08/25, .06/25, .04/25, .03/25, .02/25, .03/30) utilizing the techniques discussed
dentist to have a new crown fabricated. Additional cases using a similar decision making process, technique, and sequence are illustrated in Figures 4 and 5. A challenging clinical case has been described discussing the risk factors and preoperative treatment planning that took place prior to initiating the treatment. Treatment steps have been discussed. Emphasis has been placed on avoidance of iatrogenic events, informed consent, achievement of patency, and designing treatment to preserve tooth structure and optimize irrigation and obturation hydraulics. I welcome your feedback. EP
Figure 5C: Preoperative cone beam image slices (Pro-Max® 3D s, Planmeca,) of the clinical case retreated in 5A-5B
The TF Adaptive System
PRODUCT PROFILE
The TF Adaptive System by Axis | SybronEndo is a new NiTi file system designed to work with the Elements motor which features Adaptive Motion
Three benefits of the TF Adaptive system and Adaptive Motion Technology:
You’re in control.
Adaptive Motion Technology is based on a patented smart algorithm and designed to work with the TF Adaptive System. This technology allows the TF Adaptive file to adjust to intracanal torsional forces depending on the amount of pressure placed on the file. This means the file is in either a rotary or reciprocating motion, depending on the situation. The result is exceptional debris comparable to that found with our classic rotary Twisted File design but with less chance of file pull-in provided by our Adaptive Motion Technology. Now that’s rotary when you want it and reciprocation when you need it.
Keep it simple.
TF Adaptive uses an intuitive color-coded system designed for efficiency and ease of use. Just like a traffic light — start with green and stop with red.
The TF Adaptive System also allows dentists and endodontists to use a minimum number of files to complete the shape of the root canal. “In many cases we only have to use two NiTi files to treat the tooth,” Dr. Gary Glassman says, “one to create the taper and one to apically enlarge.”
Peace of mind.
The TF Adaptive file design is based on our clinically proven Twisted File technology, which means the file is twisted to shape for improved file durability, features R-Phase technology to improve file flexibility, and provides exceptional debris removal. So with TF Adaptive and Adaptive Motion, you get the best of both worlds. Rotary when you want it and reciprocation when you need it.
If you would like to learn more about TF Adaptive and Adaptive Motion technology, please contact us at 800-346-3636 or visit tfadaptive.com.
This information was provided by Axis | SybronEndo.
42 Endodontic practice Volume 6 Number 2
EP
Rotary when you want it and reciprocation when you need it.
You’re in control > TF Adaptive is designed to work with our ElementsTM Adaptive Motion Technology, which allows the TF Adaptive file to self-adjust to intra-canal torsional forces. In other words — rotary when you want it and reciprocation when you need it.
Keep it simple > An intuitive, color-coded system designed for efficiency and ease of use.
Peace of mind > TF Adaptive is built on the success of the Classic TF design and includes the same advanced Twisted File technology.
Trusted by Gary Glassman, D.D.S.EndodontistToronto, Canada
Radiograph courtesy of Dr. Gary Glassman.
Confidence in your hands.
®
For more information contact Axis|SybronEndo at 800.346.3636 or visit tfadaptive.com/confidence.
tfadaptive.com/confidence
PIPS™ Laser Endo
PRODUCT PROFILE
PIPS™ Laser Endo harnesses the power of the Lightwalker Dual Wavelength Laser: improving clinical results and patient treatment acceptance
Lasers have been used in dentistry for decades, but they have become widely
accepted, and now tens of thousands of dentists in the U.S. and around the world are using lasers for a wide range of procedures, including laser endo, perio, osseous procedures, no shot/no drill cavity preparations, biostimulation, and soft and hard tissue surgery. Market acceptance of dental lasers is growing rapidly in response to improved clinical results and patient demand. The decision is no longer whether to add lasers to your practice; it is just a matter of which laser(s) will best fulfill your clinical needs and objectives. LightWalker procedures are typically faster, easier to perform, and more effective. Laser treatments are, by nature, minimally invasive, and Lightwalker takes this concept to a new level. This allows you the opportunity to improve clinical outcomes and increase your production and ROI. Photo Activated Systems Technology, or PHAST™, is the scientific foundation for the Lightwalker Er:YAG and the basis for PIPS™ as well as other advanced clinical laser procedures. Variable Square Pulse (VSP) technology raises the bar for precision, speed, comfort, reliability, and safety. Lightwalker’s next generation pulse shaping sets a new standard for dental laser performance, and makes the system ideal for a wider range of applications. Different dental procedures require different laser wavelengths. Wavelength is important because specific body tissues (chromophores) interact in different ways depending on the particular laser source. Therefore, it is important to use the proper wavelength that is tissue specific for the procedure. The Lightwalker Er:YAG laser is uniquely suited for optimum performance of PIPS™ laser endodontic treatments due to several advanced technological developments. The first is the Er:YAG’s 2940nm wavelength, which has the highest absorption rate in water, 300% higher than other erbium wavelengths. This high affinity for water is necessary to create photo acoustic waves.
The second critical technical advancement is Lightwalker’s super short, 50 microsecond (VSP) duration, combined with the efficient design of the PIPS™ tip, which allows for the lowest possible energy per pulse (millijoules) and repetition rate (hertz), minimizing thermal effects and maximizing the propagation of the PIPS™ waves.
Shorter pulse durations and pulse shapesThe combination of the high absorption rate in water, the 50 microsecond VSP pulse, and the patented PIPS™ tips gives the Lightwalker the ability to effectively create photo acoustic waves that the PIPS™ procedure uses within the cleaning and debriding solutions in the canal. The containment of the waves thoroughly streams these solutions three-dimensionally through the entire canal system, enhancing their effectiveness. The canals and subcanals are left clean, and the dentinal tubules are free of smear layer.In addition to PIPS™, PHAST™ technology is ideal for a wide range of advanced clinical laser procedures:
Osseous crown lengthening - Flapless and suture-free osseous crown lengthening.
Laser implant recovery - Allows you to perform fast, bloodless, and safe removal of excessive gingival tissue around the implant prior to seating the implant.
Cavity preps without anesthesia - Fast, conservative, pain-free cavity preps, treat multiple quads in one visit.
Laser troughing - Packing retraction cord is often frustrating, unpredictable, and time consuming. Laser troughing can help you get clean, bloodless, high quality impressions the first time around.
Laser soft tissue crown lengthening - Allows you to remove excess tissue without a scalpel, sutures, or bleeding to obtain immediate impressions for crown and bridge procedures, and cosmetic procedures. Typically, there is less need
for postoperative pain medication, making the procedure more comfortable for your patients.
Laser gingivectomy - Used for general cosmetic purposes and also for impressions for cosmetic and crown and bridge procedures. Excess tissue can be quickly and predictably contoured without bleeding, reduced postoperative pain, and medications when compared to scalpels and sutures.
Laser sulcular debridement and curettage - Used as an adjunct to traditional scaling and root planning in order to reduce pocket depths.
Laser frenectomy - Allows for bloodless, scalpel and suture-free release of maxillary or mandibular frenums.
44 Endodontic practice Volume 6 Number 2
Research is confirming the efficacy of Lightwalker PHAST procedures and PIPS™ laser endo:
Malterud M. Minimally invasive biomimetic endodontics: the future is here. Gen Dent. 2013;61(1).
Jaramillo DE, Aprecio RM, Angelov N, DiVito E, McClammy TV. Efficacy of photon induced photoacoustic streaming (PIPS) on root canals infected with enterococcus faecalis: a pilot study. Endod Practice US. 2012;5(3).
Peters O, Bardsley S, Fong J, Pandher G, DiVito E. Disinfection of root canals with photon-initiated photoacoustic streaming, J Endod. 2011;37(7).
DiVito E, Colonna M, Olivi G. The photoacoustic efficacy of an Er:YAG laser with radial and stripped tips on root canal dentin walls: an SEM evaluation. J Laser Dent. 2011;19(1):156-161.
Olivi G, Crippa R, Iaria G, Kaitsas V, DiVito E, Benedicenti S. Laser in endodontics (part II). roots. 2011;7(2).
Olivi G, Crippa R, Iaria G, Kaitsas V, Benedicenti S, DiVito E. Laser in endodontics (part I). roots. 2011;7(1).
Olivi G, Crippa R, DiVito E, Iaria G, Kaitsas V. Laser in endodontics: a review and outlook. Endo Tribune, Italian Edition. 2010;2(4).
Newman K. Open wide: phontonics lights up endodontics. Biophotonic. 2012;(1):42-46.
DiVito E, Peters OA, Olivi G. Effectiveness of the erbium:YAG laser and new design radial and stripped tips in removing the smear layer after root canal instrumentation. Lasers Med Science. 2012;27(2):273-280.
Diaci J, Boris Gaspirc B, Comparison of Er:YAG and Er,Cr:YSGG lasers used in dentistry. J Laser Health Acad. 2012;1.
This information was provided by Technology4Medicine.
EP
Our endodontic irrigation regimen is scientifically tested and proven to give
you the best approach to cleansing canals when used in conjunction with normal instrumentation. Irrigation has a central role in end-odontic treatment because instrumentation leaves 35% of the canal untouched. During and after instrumentation, the irrigants facilitate removal of microorganisms, tissue remnants, and dentin chips from the root canal through a flushing mechanism. Using a combination of products in the correct irrigation sequence contributes to a successful treatment outcome.
Chlor-Xtra™ multiple patents pendingChlor-Xtra™ is an enhanced 6% sodium hypochlorite solution designed for irrigation, debridement, and cleansing of root canals during and after instrumentation. The addition of powerful wetting agents and proprietary surface modifiers enables it to penetrate into lateral canals and isthmuses by lowering the surface tension. Scientific research shows that sodium hypochlorite with added surface active agent was most effective in tissue dissolution in all experimental situations.1
Compared to standard Sodium Hypochlorite Chlor-XTRA™ offers:• 2+ times more tissue dissolution• 2+ times more digestive
• Works four times faster than standard sodium hypochlorite
• 50% less surface tension• Greater oxidizing power• Reduces post-treatment complications• Added surfactants increase lubricity and
improve contact
EDTA 17% solutionRemoval of smear layer and dentin mud.Not all EDTA solutions are created equal! EDTA works better to remove smear layer when it is at an optimal pH level. Vista’s EDTA at a pH level of 8.5 is scientifically proven to be a more powerful chelating agent to dissolve smear layer and dentin mud. EDTA opens dentin tubules and prepares dentin walls for better adhesion of filling materials.
SmearOFF™
Vista’s new SmearOff removes smear layer, AND bacteria. One product, multiple benefits.Vista’s new EDTA based formula is enhanced with chlorhexidine for added antibacterial properties. Used after sodium hypochlorite for one-step smear layer removal and disinfection. Unlike other mixes, SmearOff is compatible with sodium hypochlorite; eliminating steps and saving time with each procedure. SmearOFF removes signifi-cantly more canal debris com-pared to standard 17% EDTA, and leaves the root canal surface
cleaner by opening a greater percentage of dentin tubules. Additionally, SmearOFF provides the added benefit of killing root canal bac-teria.• Superior chelation and enhanced cleansing• Optimal smear layer removal
• Kills 99.99% bacteria in 10 seconds**Independently confirmed by Nelson Labs;Time kill study protocol #STP0158.2
CHX-Plus™ multiple patents pendingThe final irrigation step for long-lasting cleansing.CHX-Plus™ contains 2% chlorhexidine gluconate plus powerful wetting agents and proprietary surface modifiers to improve the depth of penetration and kills bacteria 10X faster than normal 2% chlorhexidine. CHX-Plus™ is a relatively new product for endodontic disinfection that is proving to be a must for final irrigation before obturation. Scientific studies show that CHX-Plus™ demonstrates higher levels of bactericidal activity at all exposure times than 2% CHX. Compared with regular 2% CHX, treatment with CHX-Plus™ was considerably more effective against biofilm bacteria in mature and nutrient-limited phases.2
46 Endodontic practice Volume 6 Number 2
PRODUCT PROFILE
Vista SOLUTIONS.
Tested and proven for superior outcomes
This information was provided by Vista Dental Products.
REfEREncEs
1. Stojicic S, Zivkovic S, Qian W, Zhang H, Haapasalo M. Tissue dissolution by sodium hypochlorite: effect of concentration, temperature, agitation, and surfactant. J Endod. 2010;36(9):1558-1562.
2. Shen Y, Qian W, Chung C, Olsen I, Haapasalo M. Evaluation of the effect of two chlorhexidine preparations on biofilm bacteria in vitro: a three-dimensional quantitative analysis. J Endod. 2009;35(7):981-985.
EP
ENDODONTIC SOLUT IONSVISTA. Mountains Above the Rest.
6% sodium hypochlorite solution enhanced with surface modi� ers Compare to Ultradent® ChlorCid®*503800 $60.95
EDTA 17% Solution Lower pH for smear layer removal Compare to Ultradent® EDTA*317011 $51.45
CHX- Plus™ Multiple patents pending
Long-lasting � nal cleansing irrigation Compare to Ultradent® Consepsis®*503900 $57.00
*Not a registered trademark of Vista Dental Products.
One product, multiple bene� ts. Removes smear layer AND bacteriaCompare to Sybron Endo® Smear Clear®*● Superior chelation and enhanced cleansing● Optimal smear layer removal ● Kills 99.99% e.faecallis bacteria
Good through April 30, 2013
Buy 3Get 1 FREE
}MIXand
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OR GET 1 FREE16oz bottle of NEWSmearOFF™
patent pending
Endo Practice_fullpg_Mar-Apr 2013.indd 1 2/14/2013 8:56:57 AM
Current ultrasonic tips on the market are very expensive. This has limited
the use of ultrasonics in endodontics. The engineering team at Engineered Endodontics™ wanted to create a product that would perform like the current single piece tips, but cost a fraction of the price. In doing so, Engineered Endodontics™ created the Vari™ -Tip. The Vari™ -Tip is a two-piece tip system, which consists of a base and interchangeable tips. The inspiration for the Vari™ – Tip came from shaving razors that have a permanent razor handle, and the user must buy disposable razor blades. The bases of the Vari™ -Tip are permanent; come in 3 different angles for holding the tips (30, 45, and 60 degrees), and fit all common ultrasonic units. The tips are a multi-use disposable and currently come in common access and refinement tip shapes; taper with and without diamond, ball (with diamond), and football (with diamond). All the tips quickly and easily attach to any Vari™ -Tip base. The entire Vari™ -Tip system is produced in the U.S. out of surgical-grade stainless steel and uses medically approved diamond plating. So practitioners do not have to worry about Chinese steel or Indian plating where traceability and compliance are often ignored and quality sacrificed. This patent-pending, two-piece system allows practitioners to create the ultrasonic tip they need, when they need it, at a fraction of the cost compared to current single piece tips. Current single piece tips on the market range in price from $48 to over $100. According to the American Association of Endodontists (AAE), endodontists spend on average between $3,900 to over $5,000 a year on ultrasonic tips. (This number comes from the last published data on annual root canal treatments performed by endodontists.) If the same number of Vari™-Tips were purchased instead of the single piece tips, the savings for the practitioner would be an average of $3,500 per year. Vari™-Tips come in packs of three tips for $48 per pack. The bases come in packs of three as well, one of each angle and a wrench for $69, as well as three of one angle and wrench for $69. Individual bases with
wrench included can also be purchased for $30. Engineered Endodontics™ is currently running a promotion; buy any three packs of tips, and the pack of variety bases is free. That’s nine ultrasonic tips for $144.
Vari™ -Tip uses include:• Precise and safe removal of tooth
structure• Findandlocatecanals• De-roofing peripheral dentin and flaring
Vari™ -Tip bases have a standard 3mm x 0.6mm thread and will fit the following units: Vista, P5, ProUltra, NSK, SybronEndo, Obtura Spartan, J. Morita, and Dentsply/Tulsaunits.
This information was provided by Engineered Endodontics LLC.
Vari™-Tip
48 Endodontic practice Volume6Number2
PRODUCT PROFILE
Engineered Endodontics™ is revolutionizing the ultrasonic tip market with the Vari™-Tip, the first customizable, cost efficient, all-metal ultrasonic tip
The Vari™-Tip ultrasonic tip line from Engineered Endodontics, LLC
EP
“The straight tip performs nicely, in a similar way as a BUC 1 tip. Overall, I am impressed with the
instruments, and the cost savings versus buying the entire tip as
one unit is very logical.”– Dr. Brett Gilbert
“The ultrasonic tips with their two-piece construction are as efficient as the one-piece tips
that I have been using, but at a fraction of the cost.”
My new endodontic instrument company has provided an exciting,
interesting, and sobering experience of endodontics in America today. Exciting because teaching is a personal passion. Interesting because it allows me to stay in touch with old friends and make new ones. Sobering because it reinforces the severity of the challenges confronting today’s clinicians (endodontists and general dentists alike). A case in point from the sobering experience: this past week an endodontist told me his local endodontist competitors had contracted to do molar treatments for $400 per tooth for an insurance company — a reality with significant impact on his practice. This man is not alone facing headwinds. Huge dental corporations have changed the face of dental delivery forever across America, as many of these corporations do not refer root canals outside their groups, even if they have no endodontists on staff. Extraction and implants are, in some quarters, recommended arbitrarily without consideration for tooth retention and retreatment. Location and personal situation dependent, these and other forces have made endodontics a tough business in 2013. This is real world endodontics. Is the future doom and gloom? What can be done to face these challenges? I do not believe in post modernism — a world view that all of life is open to interpretation and is situational, i.e., a lack of belief in absolute truth and unflinching values. I believe in absolute truths. Neither am I a management consultant nor do I pretend to have all the answers. I am just a full-time endodontist who has faced, will face, and now faces many of
the same challenges. But, as it relates to endodontics, these are my foundational truths — principles I believe are the best response to today’s headwinds:
1) We are the captains of our teams (offices), and we are responsible for every aspect of our team’s performance (clinical and personal service, financial results including overhead, containment, etc.), not outside forces. Over the long term, there can be no excuses for poor performance. Financial success flows from providing excellent clinical and personal service and efficiently running our offices as the small businesses they are. Sir Alex Ferguson is the manager of Manchester United football (soccer) team
— the most decorated manager in the history of British football. In 25 years, he has won an astounding 24 major trophies. Manchester United is not a democracy; it’s Fergie’s way or the highway. He dictates the team selection and tactics. We all could learn from Sir Alex. Our offices are not democracies. Just like Sir Alex, we dictate the selection (personnel) and tactics (our systems) of our teams. All our “players” must commit, comply, and work cooperatively to achieve the team’s goals. If not, they should be made free agents to play on another team.
2) The best marketing is clinical success and happy patients. No one is 100% successful clinically, but if we are continuous students, we will improve. Having happy patients requires answering their three questions conclusively: A) Will the doctor listen to me?
Building a bright endodontic futureDr. Rich Mounce offers some tips on improving practice performance
Listening assures our patients we care.
B) Is this going to hurt? Never treat a patient who is
uncomfortable.
C) How much is this going to cost? If a patient chooses the $400 option
for a molar root canal — he/she knows the price of everything, and the value of nothing. There is a reason a new Panerai watch costs exponentially more than a Timex. Quality has a price.
3) We do not have to be all things to all people. Life is too short to work on unhappy people. Work on who you like, doing what
you like to do. If you don’t love what you are doing, maybe you should not be doing it.
4) Finally, the cream rises to the top. If your heart is set on opening or buying an office in the proverbial lion’s den of an already saturated community, you must believe in your soul that you cannot fail (inspiration), and then do everything in your power to succeed (perspiration) — Steve Jobs did. And finally, know that you are not alone, that there are kindred spirits out there, guys like me who believe in the possible and will do the hard work to overcome obstacles — a guy who, along with his devoted wife, is in the lion’s den with the big boys of the endodontic supply world and loving the exciting, interesting, and sobering experience, every single day. I welcome your feedback.
Dr. Rich Mounce is in full-time endodontic practice in Rapid City, South Dakota. He has lectured and written globally in the specialty. He owns MounceEndo, LLC, marketing the rotary nickel-titanium MounceFile in
The best marketing is clinicalsuccess and happy patients. No one is
100% successful clinically, but if we arecontinuous students, we will improve.
EP
Volume 6 Number 2 Endodontic practice 49
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AbstractPurpose: The purpose of this study was to determine whether autoclave sterilization following simulated clinical use causes degradation of System B™ Heat Source pluggers (SybronEndo), and to determine if common oral pathogens on the carrier surface can survive routine heat activation. Materials and methods: Twenty 0.06 taper Buchanan pluggers were divided into four groups (n=5): group 1—sterilization only; group 2—simulated clinical use only; group 3—simulated clinical use and sterilization; group 4—control (unused/unsterilized). Simulated clinical use consisted of down-packing gutta-percha/sealer in three pre-shaped acrylic canals. During 5-second heat activation at 200°C, a custom-designed thermocoupling device measured each plugger’s maximum temperature at 0-cycles (baseline) and following 25, 50, 75, 100, 125, and 150-cycles of simulated use and/or sterilization. Additionally, pluggers from groups 3 and 4 were individually inoculated with Streptococcus mutans, Candida albicans, or Enterococcus faecalis, heated for 3 or 6 seconds at 200°C, and the killing efficiency was then evaluated by plating. Results: Following 150 cycles, the mean temperature for group 3 was significantly lower than group 2 (p=0.028). The mean temperature of group 1 was only marginally lower than group 2 (p=0.055). Additionally, no colony forming units of S. mutans or
C. albicans were seen after 3-second heat activation. E. faecalis, however, was not completely eliminated from any of the tested pluggers at 3- or 6-second heat activations. ConclusionsThe heating capacity of System B Heat Source pluggers declined following 150 use and sterilization cycles. A similar effect was not observed for instruments subjected to simulated clinical use only. Additionally, E. faecalis demonstrated the ability to survive routine heat activation.
IntroductionSuccessful endodontic therapy is, in part, dependent on a complete, three-dimensional obturation of the root canal space.1 One of the most common causes of endodontic failure is incomplete obturation.2 Thermoplasticized gutta percha has the ability to fill the root canal system three dimensionally, while providing an adequate seal of the root apex. When the commercial beta form of gutta percha is heated to 42-49°C, (107-120°F), it undergoes a phase conversion to its raw, alpha form. Continued heating to 53-59°C (127-138°F) initiates another phase transition to a flowable, amorphous state.3 Heat carriers, such as the System B Heat Source, are commonly used to make this phase transition occur. Predictable treatment outcomes using the System B heat carrier are
dependent on the ability of the heat source to plasticize the gutta percha, while not damaging associated periodontal tissue.4-7 Increased external root temperatures of 10°C have been shown to be detrimental to the surrounding periodontium.8 The safe and effective use of the System B unit is dependent on the ability of the carrier to predictably and promptly reach its appropriate temperature. Insufficient heat may fail to plasticize the gutta percha near the root apex, resulting in a deficient seal, while excessive heat has the potential to injure the surrounding bone and periodontal ligament. Temperature settings above 250°C have been shown to cause root surface temperatures to rise 10 degrees, subjecting the periodontium to risk.9 Clinically, there is no practical means to verify whether the temperature on the System B unit display represents the actual heat level being transmitted through the plugger to the gutta percha. Several studies have failed to find a correlation between the temperature indicated on the liquid display, and a temperature measurement taken by attaching a thermocouple directly to the plugger.10-11 This would suggest that practitioners might use heat carriers at considerably different temperatures than what they perceive them to be. The manufacturer advises users to expect decreased heating ability over time, but the rate of degradation, and whether sterilization contributes to this, is
Effect of repeated sterilization and simulated clinical use on the heating capacity of System B™ Heat Source pluggers
50 Endodontic practice Volume 6 Number 2
RESEARCH
Drs. Steven W. Black, Brian E. Bergeron, Mark D. Roberts, Jacob P. Bitoun, Zezhang T. Wen, Van T. Himel, and Joseph L. Hagan, MSPH, explore possible degradation and pathogens related to routine heat activation
Figure 1: Custom-designed plugger heat transfer positioning model and recording device
Steven W. Black earned his DDS from Case Western Reserve University in 2002 and his Advanced Education in General Dentistry Certificate from Langley AFB, Virginia in
2003. He earned his Certificate in Endodontics from Keesler Medical Center USAF in 2012.
Steven W. Black, DDS, Brian E. Bergeron, DMD, and Mark D. Roberts, DMD, are from the Keesler Medical Center USAF, Biloxi, Mississippi. Jacob P. Bitoun, PhD, Zezhang T. Wen, PhD, Joseph L. Hagan, MSPH, and Van T. Himel, DDS, are from the Louisiana State University Health Sciences Center School of Dentistry, New Orleans, Louisiana.
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Volume 6 Number 2 Endodontic practice 51
unknown. Research is limited regarding the contributing factors that cause plugger degeneration, and the rate at which a clinician should expect a decrease in performance. Appreciating the actual working temperature of the plugger makes the instrument safer and more consistently effective. The manufacturer recommends sterilization of the pluggers after every use; however, sterilization may cause more rapid degeneration of the instrument. Evidence exists that both supports and refutes the idea that multiple sterilization cycles cause metal-based endodontic instruments to deteriorate prematurely. For example, multiple sterilization cycles have been shown to cause increased depths of surface irregularities on rotary NiTi files.12 Sterilization has also been implicated in causing a significant decrease in the amount of angular deflection a stainless steel file can withstand before fracturing.13 Other studies have failed to find that multiple autoclave sterilization cycles affect different properties of endodontic NiTi files, such as torsion.14,15 This study is the first to evaluate the effects of autoclave sterilization on System B pluggers. Some clinicians may rationalize that sterilization is unnecessary due to the extreme heat under which the pluggers operate; however, it is unknown if the temperature and activation time associated with routine clinical use is sufficient to sterilize the instrument of common oral pathogens. The purpose of this study was twofold: to determine the effects of repeated sterilization and simulated clinical use on System B pluggers over 150 cycles of sterilization and/or clinical use; and to determine if common oral pathogens are able to survive routine heat activation.
Materials and methodsPart I: Plugger heat transfer predictability In order to evaluate true plugger temperatures, a positioning device was fabricated from dental supplies and lab materials, including a dowel pin, mandrel, X-ray tab, ortho resin, ballpoint pen spring, an extracted mandibular molar, and die stone. With the plugger inserted into the model as shown in Figure 1, activation temperatures of System B pluggers were recorded with the use of a Type K, 30-gauge wire thermocouple and an Oakton® Temp-300, 2-Input Thermocouple Datalogging Thermometer (Oakton Instruments). The System B unit was set to 200°C during
testing. The model was designed to ensure consistent, repeatable placement of the thermocouple wire on the terminal 2 mm of the plugger. The spring introduced tension, ensuring a tight and consistent connection force between the thermocouple wire and the plugger. Preliminary testing showed that a loose connection resulted in lower temperatures, while a tight connection provided by the ballpoint pen spring resulted in higher, more consistent temperature readings. Twenty 0.06 taper Buchanan pluggers were divided into four groups (n=5). Prior to use and/or sterilization, a baseline maximum temperature was recorded for all of the experimental pluggers. The actual maximum temperature was recorded for each plugger by placing them in the custom made model with the thermocouple loop around the last 2 mm of the plugger, and activating the System B unit at 200ºC for 5 seconds. The Data Logger recorded the temperature during the 5 seconds of activation and continued to record the temperature 15 seconds after activation as the plugger cooled. This was repeated three times, and the average maximum
temperature was recorded for statistical analysis.
Group 1: Pluggers (n=5) were subjected to a total of 150 autoclave sterilization cycles, using the STATIM 2000 Cassette Autoclave®, (SciCan, Toronto, Canada) wrapped cycle (138°C for 10 minutes). After every 25 cycles, the maximum attainable temperature of each plugger in group 1 was recorded using the thermocouple in the custom made model as described above.
Group 2: Pluggers (n=5) were subjected to simulated clinical use only without autoclaving. Simulated clinical use consisted of down-packing size 40 K3 0.04 taper gutta-percha points (SybronEndo) coated with Roth 801 Sealer in pre-shaped acrylic canals. One cycle of simulated clinical use consisted of three down-packs, and pluggers were subjected to 150 total cycles, using the custom made model and thermocouple to measure maximum attainable temperatures after every 25 cycles. Canals were 15 mm long, and down-packing was accomplished by
Buy three packs of Vari,67,89:';<='>?'>8@@'8<A@B=?';'9;AC'DE'F;:?:'EDG')-HH! "7894:(;<;=(>?9@8:A;<B(9<C:(8;D(8(:=9(AE(F8:=:(EA@(A;?G(HIJJK
activating the System B unit for 3 seconds while slowly advancing the plugger to within 2-3 mm of the overall canal length. Each plugger was wiped clean with a Sani-Wipe after each cycle of simulated clinical use.
Group 3: Pluggers (n=5) were subjected to simulated clinical use as group 2, followed immediately by sterilization using the protocol in group 1, for a total of 150 cycles, using the custom made model and thermocouple to measure maximum attainable temperatures after every 25 cycles.
Group 4: These pluggers (n=5) served as controls, neither sterilized nor subjected to simulated clinical use. Their purpose was to ensure that observed changes in temperature of experimental pluggers were the result of instrument degradation and not a decline in performance of the System B unit itself. Maximum attainable temperatures were similarly recorded simultaneously with groups 1-3 pluggers following every 25 experimental cycles. In order to verify continued accuracy of the thermocouple throughout experi-mentation, the wire was calibrated after every 50 cycles by placing it in a water bath heated to 70-100°C together with a standard thermometer.
Part II: Oral pathogen susceptibility to plugger heat activationThe second part of this investigation was designed to determine whether three common oral pathogens had the ability to survive on the surface of System B pluggers at routine operating temperatures (200°C on the liquid display). A single colony of C. albicans (strain DAY185) was inoculated into 10 mL of yeast peptone and dextrose (YPD) media and grown overnight at 30°C in a shaking incubator at 150 rpm. S. mutans (strain UA159), and E. faecalis (strain V583) were inoculated into 10 mL of Brain Heart Infusion (BHI) broth and grown overnight at 37°C in a 5% C02 static incubator. Overnight cultures were diluted 1:100 and grown to an optical density of 0.5. Cells were harvested by centrifugation at 4,000 rpm for 10 minutes then resuspended and washed twice with Phosphate Buffered Saline (PBS), pH 7.4, to remove any residual growth media. Cells were resuspended in equal volumes of PBS.
Microbes cultured from pluggers without heat activation: Three pluggers from groups 3 and 4 were inoculated with microbial cells by suspending 13 mm of each plugger’s tip in a solution of each of the prepared cells for 5 seconds. One plugger from group 3, and one plugger from group 4 were used for each of the microbes tested. The inoculated pluggers were washed into a solution of PBS without activating the System B unit, which served as a control to determine an initial count of microbes present on the carrier surface. S. mutans and E. faecalis were then plated on BHI with 1.5% agar. C. albicans was plated on YPD agar. Each plugger was tested three separate times, and cultured in triplicate.
Microbes cultured from pluggers following heat activation: The same pluggers from groups 3 and 4 were once again inoculated similarly with the same microbial cells. Inoculated pluggers were then pulsed for either 3 or 6 seconds with the System B unit set at 200°C. Then the pluggers were washed into a sterile PBS solution, mixed thoroughly, and then plated in triplicate in the same manner as previously described. Each plugger was
52 Endodontic practice Volume 6 Number 2
RESEARCH
tested three times. CFU’s were counted either 24 hours later (C. albicans) or 48 hours later (S. mutans and E. faecalis).
Data analysisInitially a mixed effect linear model was fit to compare groups’ change in temperature as the number of experimental cycles increased. Two quantitative factors were considered in the model: 1) the number of times the pluggers were used, and 2) the number of times the pluggers were sterilized. Subsequently, analysis of variance (ANOVA) with Tukey’s Honestly Significant Differences test for post-hoc analysis was used to compare groups’ mean maximum temperature at each level of experimental cycles. Additionally, a two-sample t-test was used to compare sterilized and non-sterilized heat carriers’ mean maximum temperature. For bacterial growth experimentation, two factor ANOVA with Tukey’s Honestly Significant Differences test for post-hoc analysis was used to compare the mean number of CFUs growing from new versus used pluggers heated for 3 and 6 seconds after being inoculated with E. faecalis. A 5% significance level was used for all hypothesis tests.
*Groups with different letters have a significantly different mean maximum temperature for the specified number of experimental cycles.
Table 1. Comparison of groups’ mean maximum temperature (ºC) for each number of experimental cycles.
Heating Time(s) nMean (SD) number of CFUs
P-valueNew Tips Used Tips
3 6 1.7 (1.6) 40.2 (18.5) <0.001*
6 3 2.3 (3.2) 4.3 (1.5) 0.996
*Indicates significant difference in survival between new and used pluggers
Table 2. Survival of E. faecalis from new and used tips heated for different time intervals.
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Volume 6 Number 2 Endodontic practice 53
ResultsPlugger heat transfer endurance After adjusting for the effect of number of times sterilized, the mixed effects linear model indicated no association (p=0.627) between the number of times the plugger was used and the temperature of the tip; but after adjusting for the effect of number of times used, there was a significant inverse relationship (p=0.002) between the number of times the plugger was sterilized and the temperature of the tip. Comparing groups’ temperature separately for each number of experimental cycles, there was no statistically significant difference between groups’ mean maximum temperature after 0 (p=0.654), 25 (p=0.742), 50 (p=0.511), 75 (p=0.445), or 125 (p=0.249) usage and/or sterilization cycles (Table 1). There were, however, significant differences between the groups’ maximum mean temperatures following both 100 (p=0.027) and 150 (p=0.010) experimental cycles. Post-hoc analysis revealed that after 100 cycles the mean temperature for group 3 (use/sterilization) was significantly lower than group 4 (control) and group 1 (sterilization only), but not group 2 (use only). Additionally, following 150 experimental cycles, the mean temperature for group 3 (use/sterilization) was significantly lower than group 2 (use only) and marginally lower than group 4 (control). In order to isolate the effect of sterilization, the results were also dichotomized into “Sterilization YES”, (groups 1 and 3) or “Sterilization NO” (groups 2 and 4). No significant difference in the mean maximum temperatures of sterilized versus unsterilized pluggers was found after 0, 25, 50, 75, or 100 cycles. However, the mean maximum temperature of sterilized heat carriers was significantly lower compared to unsterilized pluggers after 125 cycles (p=0.047) and 150 cycles (p=0.001), with sterilized pluggers’ mean maximum temperature an average of 8.6°C and 11.7°C lower than unsterilized heat carriers, respectively.
Oral pathogen susceptibility to plugger heat activation Three-second heat activation at 200°C of System B pluggers inoculated with S. mutans or C. albicans, resulted in a 100% killing efficiency. In contrast, E. faecalis demonstrated the ability to survive both 3- and 6-second heat activation as determined by CFUs.
In the full ANOVA model, heating time (p=0.007), plugger usage (p<0.001), and the interaction between heating time and plugger usage (p=0.006) were all significantly associated with the number of E. faecalis CFU growth. The significant interaction term indicates that the effect of heating time on the number of CFUs growing depends on whether the tip was new or used. For instruments heated 3 seconds, significantly more CFUs grew from used pluggers compared to new ones (p<0.001) but for pluggers heated 6 seconds, there was not a significant difference (p=0.996) in the number of CFUs (Table 2). Regarding the effect of heating time, for new instruments there was not a significant difference (p=0.998) in the number of CFUs growing from pluggers heated 3 versus 6 seconds, but for used pluggers, significantly more CFUs grew from instruments heated 3 seconds compared to those heated for 6 seconds (p=0.002).
DiscussionThe initial challenge for this study was
to design a model that could accurately measure the temperature of System B pluggers without destroying them for subsequent testing. The manufacturer uses a thermocouple welded to a metal probe to calibrate new or repaired System B units, making heat transfer extremely efficient. This model’s ballpoint pen spring helped ensure that the connection between the thermocouple and the plugger metal surface was intimate, resulting in consistent temperature measurements closer to the 200°C on the System B liquid display. This novel model proved accurate and reliable, allowing for repeat experimentation of the same pluggers. The results suggest that initial deterioration of System B pluggers may occur after approximately 125-150 sterilization cycles. Additionally, clinical use combined with sterilization also resulted in significantly lower temperatures compared to unsterilized instruments after 100 and 150 cycles. The 8.6°C and 11.7°C respective decline after 125 and 150 sterilization cycles, although significant, did not appear to affect performance during experimental obturation. Theoretically,
THE ORIGINAL PLASTIC ENDODONTIC ROTARY FINISHING FILE IS BACK.
MANUFACTURER DIRECT.
MADE IN THE U.S.A.
REfEREncEs
1. Schilder H. Filling root canals in three dimensions. Dent Clin North Am. 1967;11:723-744.
2. Ingle JI, Simon JH, Machtou P, Bogaerts P. Endodontic success & failure: The Washington study. In: Ingle JI, Backland LK, eds. Endodontics. 5th ed. Hamilton, Ontario, Canada: BC Decker; 2002;748-757.
3. Schilder H, Goodman A, Aldrich W. The thermomechanical properties of gutta-percha. 3. Determination of phase transition temperatures for gutta-percha. Oral Surg Oral Med Oral Pathol. 1974;38(1):109-114.
4. Fors U, Jonasson E, Berquist A, Berg JO. Measurements of the root surface temperature during thermo-mechanical root canal filling in vitro. Int Endod J. 1985;18(3):199-202.
5. Hardie EM. Heat transmission to the outer surface of the tooth during the thermo-mechanical compaction technique of root canal obturation. Int Endod J. 1986;19:73-77.
6. Gutman JL, Rakusin H, Powe R, Bowes WH. Evaluation of heat transfer during root canal obturation with thermoplasticized gutta-percha. Part II. In vivo response to heat levels generated. J Endod. 1987;13(9):441-448.
7. Saunders EM. In vivo findings associated with heat generation during thermomechanical compaction of gutta-percha. 1. Temperature levels at the external surface of the root. Int Endod J. 1990;23(5):263-267.
8. Eriksson AR, Albrektsson T. Temperature threshold levels for heat-induced bone tissue injury: a vital-microscopic study in the rabbit. J Prosthet Dent. 1983;50(1):101-107.
Changes in root surface temperatures with in vitro use of the System B HeatSource. J Endod. 1999;25(9):593-595.
10. Venturi M, Pasquantonio G, Falconi M, Breschi L. Temperature change within gutta-percha induced by the System-B Heat Source. Int Endod J. 2002;35(9):740-746.
11. Silver GK, Love RM, Purton DG. Comparison of two vertical condensation obturation techniques: Touch ‘n Heat modified and System B. Int Endod J. 1999;32(4):287-295.
12. Valois CR, Silva LP, Azevedo RB. Multiple autoclave cycles affect the surface of rotary nickel-titanium files: an atomic force microscopy study. J Endod. 2008;34(7):859-862.
13. Mitchell BF, James GA, Nelson RC. The effects of autoclave sterilization on endodontic files. Oral Surg Oral Med Oral Pathol. 1983;55(2):204-7.
14. Hilt BR, Cunningham CJ, Shen C, Richards N. Torsional properties of stainless-steel and nickel-titanium files after multiple autoclave sterilizations. J Endod. 2000;26(2):76-80.
15. Casper RB, Roberts HW, Roberts MD, Himel VT, Bergeron BE. Comparison of autoclaving effects on torsional deformation and fracture resistance of three innovative endodontic file systems. J Endod. 2011;37(11):1572-1575.
16. Baumgartner JC, Watts CM, Xia T. Occurrence of Candida albicans in infections of endodontic origin. J Endod. 2000;26(12):695-698.
17. Nair PN, Sjögren U, Krey G, Kahnberg KE, Sundqvist G. Intraradicular bacteria and fungi in root-filled, asymptomatic human teeth with therapy-resistant periapical lesions: a long-term light and
electron microscopic follow-up study. J Endod. 1990;16(12):580-588.
18. Sedgley C, Nagel A, Dahlén G, Reit C, Molander A. Real-time quantitative polymerase chain reaction and culture analyses of Enterococcus faecalis in root canals. J Endod. 2006;32(3):173-177.
19. Molander A, Reit C, Dahlén G, Kvist T. Microbiological status of root-filled teeth with apical periodontitis. Int Endod J. 1988;31(1):1-7.
20. Sedgley CM, Lennan SL, Appelbe OK. Survival of Enterococcus faecalis in root canals ex vivo. Int Endod J. 2005;38(10):735-742.
21. Bradley CR, Fraise AP. Heat and chemical resistance of enterococci. J Hosp Infect. 1996;34(3):191-196.
22. Figdor D, Davies JK, Sundqvist G. Starvation survival, growth and recovery of Enterococcus faecalis in human serum. Oral Microbiol Immunol. 2003;18(4):234-239.
23. Evans M, Davies JK, Sundqvist G, Figdor D. Mechanisms involved in the resistance of Enterococcus faecalis to calcium hydroxide. Int Endod J. 2002;35(3):221-228.
24. Stevens RH, Grossman LI. Evaluation of the antimicrobial potential of calcium hydroxide as an intracanal medicament. J Endod. 1983;9(9):372-374.
25. Turk BT, Sen BH, Ozturk T. In vitro antimicrobial activity of calcium hydroxide mixed with different vehicles against Enterococcus faecalis and Candida albicans. Oral Surg Oral Med Oral Pathol Oral Radiol Endod. 2009;108(2):297-301.
54 Endodontic practice Volume 6 Number 2
RESEARCH
should clinicians begin to perceive reduced efficiency of sterilized pluggers after 100 plus cycles, a modest increase in temperature setting would presumably compensate appropriately for the loss of heat transfer capability. Additional research opportunities might include increased number of sterilization cycles or increased operational temperatures to determine whether the decreased plugger heat transfer observed using this protocol remains static, linear, or exponentially progressive. The manufacturer advises users to expect decreased life expectancy if pluggers are used at maximum temperatures and maximum power settings. Additionally, straight, acrylic canals were obturated for this study. More rapid decline in performance might occur if pluggers are repeatedly bent to accommodate curved canal systems in a clinical environment. S. mutans is the major causative agent of human dental caries and known for its ability to survive in various detrimental conditions encountered in the oral cavity. C. albicans is also an opportunistic pathogen that has been found in primary endodontic infections16, as well as persistent lesions
following endodontic treatment.17
E. faecalis, as the most prevalent organism in secondary root canal infections,18-19 is also known for its ability to survive and adapt to unfavorable conditions, including starvation and heat.20 According to Bradley, et al., a strain of vancomycin-resistant E. faecalis was able to survive exposure to 80ºC temperatures for 3 minutes.21 E. faecalis has the ability to survive in a minimal metabolic state, making it unsusceptible to traditional antibiotics.22 It can also survive a wide pH range; therefore calcium hydroxide cannot predictably eliminate it from the root canal system.23-25 E. faecalis demonstrated a resistance to heat not seen in either S. mutans or C. albicans. Both new and used/sterilized pluggers were able to completely eliminate both S. mutans and C. albicans after only 3 seconds of routine heat activation (200ºC setting). Surprisingly, E. faecalis could not be eradicated even after 6 seconds of heat application. Our results showed that significantly more E. faecalis survived from the used/sterilized pluggers after heat treatment compared to the new (control group)
instruments. These results might suggest that worn pluggers have the capacity to harbor more bacteria, or that the decreased heating capacity of the used/sterilized pluggers makes them less effective in reducing the bacterial load. In conclusion, this study would suggest that System B pluggers are not self-sterilizing instruments and should be autoclaved after every use. Initial decline in heat transfer reliability was unseen until 125 cycles, making System B plugger sterilization a cost effective, appropriate, and necessary part of treatment.
Acknowledgement: The authors wish to
gratefully acknowledge SybronEndo for their
generous donation of System B Heat Source
Pluggers to facilitate this resident research. The
authors deny any conflicts of interest related to
this study. This article is the work of the United
States government and may be reprinted
without permission. Opinions expressed herein,
unless otherwise specifically indicated, are those
of the authors. They do not represent the views
of the Department of the Air Force or any other
department or agency of the United States
government.
EP
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The trouble is the endodontic clinician does not necessarily know what
Anatomy Matters in advance of treatment. We, of course, do know that Anatomy Matters when lesions of endodontic origin (LEOs) develop or do not heal following an endodontic treatment to produce the endodontic seal. While failure to seal does not mean failure to heal (billions of endodontic treatments are short of the mark and have intact lamina dura, a healthy periodontal ligament, and are asymptomatic), failure to heal always means failure to seal.1 And your next patient’s precise significance of anatomy in preventing or curing LEOs is all quite unpredictable: one patient’s tooth might be fine with a weak endodontic obturation 5 mm short, at least at this point in time, while your patient has continued endodontic disease when you miss a lateral canal off a lateral canal! Patients with underfilled portals of exit can be referred to the endodontist with a variety of underfilled endodontic seals: short fills, overextensions of underfilled canals, torn or stripped foramina, perforations, resorptions, ledges, missed canals, or broken file.2 Unfortunately, much of the endodontics being taught today, while perhaps not intended, is being interpreted, understood, and accepted by the restorative dentist as “just purchase this magic instrument(s) and use this special ‘tool’ to ‘fill the canal,’
and it is easy and fast.” Often, the entire last few essential and critical millimeters of the root canal system do not quite make it into the sales conversation, and the result is that most endodontic referrals are for retreatments due to blocks, ledges, or transportations.3 Many referrals to the endodontist demonstrate unattended apical anatomy: 1) internal portal of exit transportation, 2) external portal of exit transportation, and 3) missed canal (Figure 1). However, Anatomy Matters often do not just present to the endodontist as simply “the usual.” Often, Mother Nature throws us a curve in the form of particularly complex and/or unique anatomy as is
Root canal system anatomy only matters when it matters
56 Endodontic practice Volume 6 Number 2
ANATOMY MATTERS
Dr. John West explains the importance of educating referring dentists about endodontic diagnosis and technique
John West, DDS, MSD, the founder and director of the Center for Endodontics, continues to be recognized as one of the premier educators in clinical and interdisciplinary endodontics. Dr. West received his DDS from the University of Washington in 1971 where he is an affiliate associate professor. He then received his MSD in endodontics at Boston University Henry M. Goldman School of Dental Medicine in 1975 where he is a clinical instructor and has been awarded the Distinguished Alumni Award. Dr. West has presented more than 400 days of continuing education
in North America, South America, and Europe while maintaining a private practice in Tacoma, Washington. He co-authored “Obturation of the Radicular Space” with Dr. John Ingle in Ingle’s 1994 and 2002 editions of Endodontics and was senior author of “Cleaning and Shaping the Root Canal System” in Cohen and Burns 1994 and 1998 Pathways of the Pulp. He has authored “Endodontic Predictability” in Dr. Michael Cohen’s 2008 Quintessence text Interdisciplinary Treatment Planning: Principles, Design, Implementation, as well as Dr. Michael Cohen’s soon to be published Quintessence text Interdisciplinary Treatment Planning Volume II: Comprehensive Case Studies. Dr. West’s memberships include: 2009 president and fellow of the American Academy of Esthetic Dentistry, and 2010 president of the Academy of Microscope Enhanced Dentistry, the Northwest Network for Dental Excellence, and the International College of Dentists. He is a 2010 consultant for the ADA’s prestigious ADA Board of Trustees where he serves as a consultant to the ADA Council on Dental Practice. Dr. West further serves on the Henry M. Goldman School of Dental Medicine’s Boston University Alumni Board. He is a Thought Leader for Kodak Digital Dental Systems, and serves on the editorial advisory boards for: The Journal of Esthetic and Restorative Dentistry, Practical Procedures and Aesthetic Dentistry, and The Journal of Microscope Enhanced Dentistry. Visit www.centerforendodontics.com, or email: [email protected], phone 1-800-900-7668 (ROOT), fax 253-473-6328.
Figures 1A-1F: The Endodontic Seal and endodontic failure. 1A. Radiograph of mandibular left first molar with mesial radiolucency and slight buccal swelling
Figure 1B: The mandibular molar was removed, centrifuged in red Pelikan ink, decalcified and photographed. Note two underfilled portals of exit. Dentin mud, endodontic’s fatal flaw, had blocked the canal. Insert is radiograph of mesial root
Figure 1C: Failing endodontic maxillary molar with externally stripped DB foramen. MB was internally blocked and then externally transported
Figure 1D: Endodontic failure demonstrates probable original POE penetrated with red Pelikan ink while the gutta-percha obturation, though probably iatrogenic, is actually an overfill in that the POE is sealed, and there is excess obturation material
Figure 1E: Periapical radiograph of maxillary first molar with MB radiolucency more than 2 years posttreatment
Figure 1F: Extracted Figure 1E tooth. Note missed MP canal to the right with several unfilled apical POEs to the MB area of the MB root
AN
AT
OM
Y M
AT
TE
RS
Volume 6 Number 2 Endodontic practice 57
the case with a patient with a dens in dente or dens invaginatus (tooth within a tooth).4 Joe was referred to me in 2000 for a sinus tract facial tracing to his maxillary left canine (Figure 2). The pulp tested non-vital, and the endodontic anatomy was carefully discovered and treated. A gutta-percha cone traced to the apical area of tooth No. 11. Although the CBCT imaging instrument was not available at that time, it most certainly would be helpful today. The pulpitic or non-vital dens in dente tooth is not a common referral to an endodontist, but our assignment remains the same, and that is to know all Anatomy potentially Matters all the time. The dens in dente tooth is an example that successful endodontic mechanics must be mastered by the endodontist for the “easy ones and the challenging ones” (Figure 3). At his 13-year posttreatment, Joe’s LEO and sinus tract have healed, and he reports his tooth is comfortable. Dedicated and masterful endodontists want quality control; they want to measure long-term results, and set up office structures to validate healing over time. They know, “you don’t get what you want, you get what you measure” (Figure 4). We have now referred Joe to an orthodontist for an orthodontic evaluation as tooth No. 11 is in misalignment, and he does not like the appearance of his front teeth due to the dens in dente shape and alignment. Improving his smile will have ultimately required an interdisciplinary team approach of endodontist, orthodontist, and restorative dentist. As an endodontist, the success of the referring dentist is our priority. For those referring dentists who treat some or many of their endodontic patients, we can pro-
Figures 2A-2D: Pretreatment records for maxillary left lateral dens in dente incisor. 2A. Note apparent periradicular LEO. Pulp canal with an adjacent invagination opening into the periodontal ligament
Figure 2B: Image showing lingual #10 dens in dente Figure 2C: Facial sinus tract of dens in dente Figure 2D: Gutta-percha cones tracing to apex of dens in dente
Figures 3A-3H: Internal images of before and during radicular shaping and after backpacking with vertical compaction of warm gutta percha. Figure 3A is clinical during cleaning and shaping
Figure 3B: Image of continued shaping of the “tunnels”
Figure 3C: Nature’s beauty is appreciated in her dens in dente anatomy
Figure 3D: Nature never makes two of a kind; she only knows uniqueness, and this phenomenon is displayed in the dens in dente
Figure 3E: Five conefits are made to validate desired shaping
Figure 3F: Endodontic backpack completed prior to access seal
Figure 3G: Finished obturation of dens in dente maxillary left lateral incisor
58 Endodontic practice Volume 6 Number 2
ANATOMY MATTERS
REfEREncEs
1. West J. Endodontic update. J Esthetic Restorative Dent. 2006;18:280-300.
2. West J. Perforations, blocks, ledges, and transportations: overcoming barriers to endodontic finishing. Dent Today. 2005;(1)243:68-73.
3. West J. How do masters do it? Survey presented in lecture at the annual scientific session of the American Association of Endodontists, Boston, MA. April 2012.
4. West J. Anatomy Matters. Endodontic Practice US. 2012;5(2):14-16.
5. Lichota D. Endodontic treatment of a maxillary canine with type 3 dens invaginatus and large periapical lesion: a case report. J Endod. 2008;34(6).
6. West J. Anatomy Matters. Endodontic Practice US. 2012;5(2):14-16.
7. West J. Anatomy Matters—part 2. Endodontic Practice US. 2012;5(4):26-27.
8. West J. Anatomy Matters—part 3. Furcal endodontic seal heals furcal lesion of endodontic origin. Endodontic Practice US. 2012;5(6):22-24.
9. West J. Anatomy Matters—part 4. Long-term case report. Endodontic Practice US. 2012;6(1):50-51.
vide added value to their practice when we educate them about endodontic diagnosis and technique. Knowledge can be the dif-ference that makes the difference to their endodontic outcomes. If you are currently having difficulty with busyness, here is something you can do to truly open a con-versation about endodontic anatomy and endodontic predictability: download one or more of my previous and/or present five Anatomy Matters series, and show them what they may not know.6-9 You can mail
Figure 4C: Clinical of smile distracted by underformed maxillary left lateral incisor dens in dente
Figures 4A-4D: Thirteen-year posttreatment images with interest for interdisciplinary team dentistry to optimize smile. 4A. Thirteen-year posttreatment radiographic image with LEO healing and asymptomatic
Figure 4B: Clinical close-up of healed attached gingival sinus tract
Figure 4D: Close up of needed esthetic improvement of dens in dente now biologically healed
hard copies, or better yet, teach them face-to-face. The articles should teach them to better understand the frequency of under-filled root canal systems and endodontic predictability. It should also teach them to slow down; design more successful and appropriate access cavities; irrigate prop-erly and with the right irrigants to remove biofilm, pulp remnants, and smear layer; understand glidepath for safe mechanical endodontics; and appreciate that 3D ob-turation is a direct function of shape and
obturation hydraulics during compaction regardless of technique. When you de-liver knowledge to your referring dentists that will positively change their endodontic experience, you are delivering something that, to me, is priceless.
Anatomy Matters when it matters. EP
Volume 6 Number 2 Endodontic practice 59
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Your Road Map to Stress-Free Superior Endodontics and MoreDr. Barry Lee Musikant April 5, 2013Orlando, FLwww.essentialseminars.org
Current Scientific Evidence in Endodontic Therapy Dr. Jason LangApril 12, 2013Findlay, OH www.tulsadentalspecialties.com
Pathways to Success: Endodontic Outcomes Based on Scientific EvidenceDr. Troy McGrewApril 12-13, 2013Charlotte, NC www.tulsadentalspecialties.com
Endodontic Techniques for Safe and Predictable Results: An Intense 2-Day Hands-on WorkshopDr. Barry Lee Musikant April 12-13, 2013South Hackensack, NJwww.essentialseminars.org
Current Scientific Evidence in Endodontic TherapyDr. Frank CervoneApril 19, 2013 Lake Mary, FL www.tulsadentalspecialties.com
Common Sense Endodontic Solutions from Instrumentation to RestorationDr. Barry Lee Musikant April 19, 2013Odessa, TXwww.essentialseminars.org
The Art of Endodontics 2-Day Laboratory Course Dr. Stephen BuchananApril 25-26, 2013Santa Barbara, CA www.tulsadentalspecialties.com
Current Scientific Evidence in Endodontic Therapy Dr. Donnie LuperApril 26, 2013Phoenix, AZwww.tulsadentalspecialties.com
Pathways to Success: Endodontic Outcomes Based on Scientific EvidenceDr. George BruderApril 26-27, 2013Philadelphia, PAwww.tulsadentalspecialties.com
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Great endodontics is not only possible, but attainable. This statement does
not mean endodontic treatment is routinely easy or always successful. Fortunately, with effective training, utilization of the most proven technologies, and sufficient desire, predictably successful endodontics is a cornerstone of interdisciplinary treatment. By far, the number one reason dentists give for taking endodontic training courses with me is they want to experience the so-called “thrill of the fill.” General dentists and endodontists, alike, express enthusiasm and the desire to radiographically visualize filled root canal systems. Clinical confidence soars when post-treatment radiographs reveal, for example, filled furcal canals, anastomoses, loops, deltas, or multiple apical portals of exit. More and more, dentists understand that any communication from a root canal system to the attachment apparatus is potentially significant and strongly influences predictably successful outcomes. Why is the extraction oftentimes contemplated when there is clinical and/or radiographic evidence of a lesion of endodontic origin, especially in the instance of post-treatment disease? Obviously, the extraction serves to eliminate 100% of the contents within any given root canal system. Yet, like the extraction, modern meticulous endodontic treatment also has the capacity to eliminate 100% of the pulpal tissue, and when present, bacteria and their related breakdown products. Certainly, blocked canals, apically or laterally, seriously compromise success and represent a major cause of endodontic failure. Blocked canals prevent the exchange of irrigant and clinically limit 3D disinfection and filling root canal systems. The reason for the high clinical incidence of blocked canals can be dominantly attributable to how dentists have been trained. Virtually all dentists were
taught to work short of the actual terminus of any given canal. In fact, many practice with the erroneous assumption that ideal working length is the distance measured from the selected coronal reference point, extending apically to the cementodentinal junction (CDJ). To clarify, the CDJ has also been referred to as the minor foramen, the constriction, or the preferred most apical extent of treatment. The problem with this philosophy of treatment is that the CDJ is a histological versus a clinical anatomical landmark. Numerous international published articles have clearly demonstrated that cementum on the external root surface, invaginates through the greater foramen, and extends unevenly in a coronal direction, anywhere from a few microns to several millimeters. As such, the CDJ varies from wall to wall within the same canal. Regrettably, there continues to be relentless advocacy for extending endodontic treatment to a clinically nonattainable landmark. From a practical standpoint, conscientiously working 0.5-1.0 mm short means dentists frequently end up even shorter than their intention. The desired working length is oftentimes lost because dentinal mud accumulates when grinding increasingly larger sized files apically. Compounding the problem of working short is the ill-fated philosophy that the terminal extent of virtually all canals should be enlarged to at least 0.40 mm. Needlessly large apical sizes are advocated to ensure a round foramen is prepared and, additionally, to encourage the exchange of irrigant. The clinical requirement to make a round or needlessly large foramen is simply outdated, outmoded, and irrelevant to histological facts and longstanding documented clinical outcomes. Working short and over-preparing the apical extent of a canal frequently results in an apical preparation that is both blocked and ledged. Canals are commonly blocked apically because of dentinal mud and ledged because of the over-enlarged box-shaped preparation. Most dentists equate a blocked canal to the inability to slide a small-sized hand file to the terminus. Far more insidious than apically blocked canals are laterally
blocked canals. Laterally blocked canals result when debris is compacted into the lateral anatomy when shaping canals using manual or mechanically driven instruments. It should be appreciated that canals frequently exhibit cross-sections that are not round. Debris is commonly compacted into the eccentricities off the rounder portions of canals. Equally concerning is when debris is compacted into the uninstrumentable lateral anatomy, including dentinal tubules. Once the lateral anatomy is blocked, it becomes improbable, if not impossible, to exchange irrigant laterally, compromising 3D disinfection and filling root canal systems. The prescription to avoid apical blocks is apical patency. Apical patency is encouraged by gently and deliberately sliding the apical 1 mm of a small-sized and flexible file to and minutely through the foramen. Most important, a patency file discourages the accumulation of dentinal mud. Apically unobstructed and patent canals allow the clinician to maintain the desired working length and more effectively exchange irrigants into all aspects of the root canal system. The prescription to avoid lateral blocks is to irrigate, recapitulate with a size #10 hand file, and reirrigate after using every single shaping file. Strategically, an active irrigation method can be used as soon as sufficient space is available. Active irrigation has been shown to enhance the exchange of irrigant into the uninstrumentable portions of a root canal system. I prefer the EndoActivator® (Dentsply Tulsa Dental Specialties), which has been repeatedly shown in multiple peer-reviewed articles to improve deep lateral cleaning. Much attention has been focused on avoiding or managing apically blocked canals. However, virtually no attention has been placed on the potential consequences of laterally blocked canals. Both vertically and laterally blocked canals can and do serve to sabotage predictably successful results. Keep active irrigation on your radar, and experience the thrill of the fill.
64 Endodontic practice Volume 6 Number 2
Clifford J. Ruddle, DDS, FACD, FICD, is founder and director of Advanced Endodontics (www.endoruddle.com), an international educational source, in Santa Barbara, California. Additionally, he maintains
teaching positions at various dental schools. Dr. Ruddle can be reached at [email protected].
THRILL OF THE FILLAVOIDING APICAL AND LATERAL BLOCKS
