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foundationsin dentistry

a resource from

the indiana dental association

The Indiana Dental Association is an ADA CERP Recognized Provider, and all articles herein are approved for continuing education by the Indiana State Board of Dentistry.

ADA CERP is a service of the American Dental Association to assist dental professionals in identifying quality providers of continuing dental education. ADA CERP does

not approve or endorse individual courses or instructors, nor does it imply acceptance of credit hours by boards of dentistry. Indiana Dental Association designates individualquizzes for 1 (one) continuing education credit each; completion of all 10 quizzes is designated as 10 (ten) continuing education credits. Absolutely no refunds.

Foundations in Dentistry is owned and published by the Indiana Dental Association, a constituent

of the American Dental Association, 1319 East Stop 10 Road, Indianapolis, IN 46227.

The Editor and publisher are not responsible for the views, opinions, theories, and criticisms

expressed in these pages, except when otherwise decided by resolution of the Indiana Dental

Association. Foundations is published biannually and is mailed monthly upon the placement of

individual orders.

Copyright 2013, Indiana Dental Association. All Rights Reserved.



4 · FOUNDATIONS in DENTISTRY · FoundationsInDentistry.com

Editor’s Note

Jack Drone, DDS

Self-Study Instructions

Foundations Personnel

1. Guidelines for Optimizing Success of Single Implant Crowns

Robert D. Walter, DDS, MSD

Charles J. Goodacre, DDS, MSD

2. The One Thing… Digital Dental Photography

Steve Ratcliff, DDS, MS

3. Radiographic Image Quality—Is Your Image Sharp Enough?Edwin. T. Parks, DMD, MS

4. Erosive Effects on Teeth: Clinical Strategies for the Prevention of Erosive

Tooth Wear

Anderson T. Hara, DDS, MSD, PhD

Domenick T. Zero, DDS, MS

5. What Happened to Customer Service?

Bruce Manchion

6

7

8

9

33

47

61

83

contents

table of



INDIANA DENTAL ASSOCIATION · 5

6. Innovative Management of the Periodontal Patient

Samuel Low, DDS, MS, M.Ed

7. Predictable Complete Dentures

Walter F. “Jack” Turbyll, DMD

8. The Benets of a Collaborative Approach to Complex Cases

Terry Fohey, CDT

Brantley Kitching, CDT

9. Local Anesthetic Formulations: Systemic Effects and Dosage Calculations

Daniel Becker, DDS

10. Myths vs. Realities: State-of-the-Art Indirect Posterior

Tooth-Colored RestorationsJ. Luis Ruiz, DDS

Gordon J. Christensen, DDS, MSD, PhD, ScD. PCC

93

105

129

141

155




This rst edition of Foundations in Dentistry

is a treasure for our profession. Whether

you practice in Portland, Maine, or Portland,

Oregon, the articles are relevant to you and your

entire team. We thank you for your investment

in this resource and ask that you tell others toconsider purchasing copies of their own.

The development of this book has been inspiring. Dr. Thomas Murray, an IDA trustee, and Mr. Will

Sears, IDA Managing Editor, were casually brainstorming new ways to add value to publications. A

big idea emerged from that conversation, the result of which is the impressive book in your hands.

My rst phone call to one of the prospective authors was intimidating. I had my notes for what

seemed an impossible pitch: (1) We had no money to offer authors; (2) we would need the article in

two months; and (3) the entire proceeds from the project would benet the IDA. But then the magic

of this project began. With each call, the immediate answer was, “I would love to write an article.” I

can easily say that this collection represents some of the most gracious of all of our dental colleagues,

who have dedicated their lives to their patients and fellow dentists in the name of better dentistry.

The small, faithful, team who believed in this project deserves our gratitude. The IDA’s Executive

Director, Mr. Doug Bush, is the soundest thinker I know, and a great friend. Drs. Terry Schechner and

John Roberts are respectively our outgoing and current presidents of the IDA, and wonderful friends

and colleagues. Thanks also to Drs. Jill Burns and Steven Holm, who helped with crafting quiz

questions. Members of the IDA Editorial Board, Drs. Steven Ellinwood, William Risk, and Michael

Rader, have been champions for this book, and I believe we would collectively follow each other tothe ends of the earth. The biggest thank you of all goes to Mr. Will Sears, IDA Managing Editor. In

addition to being a dear friend, he has been passionate about making this project successful.

Please enjoy this collection of articles and, if you are ever in a position to support any of the authors

beyond this book, please do. The collective generosity of our colleagues is a heartening reminder of

why organized dentistry still matters, and how our unied efforts can better our beloved profession.

Jack Drone, DDS Editor




SELF-STUDY

INSTRUCTIONS

Overview

Foundations in Dentistry was created to offer a practical, convenient solution for dental

practitioners seeking professional growth from renowned educators in the dental profession. The

format of this self-study edition lends itself to accommodating the practitioner’s busy schedule by

offering individual articles, at one credit per completed article.

Recommendations

The Editorial Board recommends the following approach to readers for gaining the most from

this educational experience:

• Start and nish one article at a time, then immediately take the quiz. This will ensure that you

grasp the intent of the author(s), and will keep the content fresh for taking the quiz.

• Use natural breaks in your daily routine, such as lunch, to complete an article and quiz. One hour

should allow for successful completion of each article and quiz for most of the articles.

• Share with your dental team. While readers must own individual copies to receive credit for the

quizzes, feel free to share the articles within your practice to develop a stronger team.

Careful Reading

The layout of this edition allows ample room in the margins for note-taking while reading, which

will prove helpful during the quiz after each article.

Quiz Response & Submission

The correct answers to each question may be found directly in, or inferred from, the text and

gures of each article. Once you have completed each quiz, sign the format the end, and submit

quiz forms to the Indiana Dental Association either all at once, or one at a time.

Obtaining Certicates of Completion

The Indiana Dental Association will provide a certicate for each completed quiz (1 hour CE)

through email, upon receipt of each quiz. Certicates are sent at the end of each month.

Let’s begin.




personnel

foundations

Editorial Board

Dr. Jack Drone, Editor

Dr. Steven P. Ellinwood, Assistant Editor

Dr. Michael D. Rader, Associate Editor

Dr. William B. Risk, Peer Review Editor

Mr. Will Sears, Managing Editor

IDA Council on Communications

Dr. Thomas R. Blake

Dr. Ted Brauer

Dr. Eric S. Browning

Dr. Lorraine J. Celis, Chair

Dr. Jack Drone

Dr. Dawn R. Durbin

Dr. P. Bruce Easter

Dr. Steven P. Ellinwood

Dr. Bruce E. Holder

Dr. Chad R. Leighty

Dr. Thomas M. Murray

Dr. Marc S. Smith

Ofcers of the Indiana Dental Association

Dr. John R. Roberts, President

Dr. Desiree S. Dimond, President-Elect

Dr. Steven J. Holm, Vice PresidentDr. Daniel W. Fridh, Treasurer

Dr. Jack Drone, Editor

Dr. Jeffrey A. Platt, Speaker, House of Delegates

Dr. Jill M. Burns, Vice Speaker, House of Delegates

Dr. Terry G. Schechner, Immediate Past President

Mr. Douglas M. Bush, Executive Director, Secretary




RADIOGRAPHIC

IMAGE QUALITY

Edwin T. Parks, DMD, MS

Abstract

High quality radiographic images are an essential component of the data collected

to generate a treatment plan. Digital imaging has diminished the impact of

processing errors, but in some instances has increased the difculty of capturing a

high-quality image. Additionally, panoramic imaging has become a more integral

component in generating radiographic information. Patient positioning errors are

the most common cause for inadequate panoramic images. The purpose of this

article is to help the clinician produce optimum radiographic images. Common

errors and their correction will be discussed for both intraoral and panoramic

radiographic imaging.

Intraoral imaging errors

Some imaging errors happen before the rst image is taken. The most common of

these errors is underexposure. If the image is too light, the diagnostic information

Is Your Image Sharp Enough?




never made it to the receptor. Exposure times

should be adjusted for tooth type and patient

size. A mandibular incisor is certainly not the

same size as a maxillary molar. A good way to

determine if your image has adequate density

is to evaluate the thickest tooth in your survey

(maxillary molar) and see if you can delineate

between enamel and dentin ( Figures 1A and

1B ). If you can’t tell the difference, the image

is too light. How can you detect dental caries

if you can’t tell the difference between enamel

and dentin in your image? The exposure time

for maxillary molars should be at least twice the

exposure of the mandibular incisors.

Receptor placement

One of the most common complaints made

by clinicians pertains to receptor placement

( Figure 2 ). It’s difcult to evaluate a third molar

when the apical third of the tooth isn’t on the

image. Our imaging goal is to capture the whole

tooth in the image but this can be challenging.

One of the main reasons for incorrect receptor

placement is patient discomfort. There are

several reasons for the patient’s complaint.

Placing the receptor too close to the tooth

often results in incomplete image capture.

Two objects cannot occupy the same space at

the same time so the image receptor must be

placed where there is room for the receptor.

For molars the best place to position the

receptor is in the midline of the mouth. The

palate is the highest in the area; the oor of the

mouth is the deepest. For anterior teeth, the

receptor should be placed near the position of

the second premolar/rst molar region; again,

the oor of the mouth is deep and the palate

is high. Another reason for incorrect receptor

placement has to do with a misinterpretation

of what “parallel” means. Placing the receptor

FIGRE 1A: Inadequate density and contrastPremolar bitewing with inadequate density and contrast. Note theindistinct delineation of the DEJ in the molars

FIGRE 2: Incorrect placementIncorrect receptor placement: this image does not capture allthe premolars or all of the molars

FIGRE 1B: Adequate density and contrastBitewing radiograph with adequate density and contrast




parallel to the long axis of the tooth is

the basis for the paralleling technique.

However, some clinicians confuse the long

axis of the tooth with perpendicular to the

oor. Consequently, the receptor is placed

perpendicular to the oor, and the patient

is expected to bite the receptor into place.

No one would bite down if it feels like they

are biting a razor blade into the roof of

their mouth, so it is unrealistic to think a

patient will bite the receptor into place.

The resultant image shows the coronal

two-thirds to the teeth, a dark band along

the inferior aspect of the receptor (for

maxillary images) and no apices ( Figure 3 ).The best way to correct this problem is to

place the receptor in the area of the greatest

space and then rotate the biteblock onto

the tooth of interest. If you are imaging

maxillary molars, place the biteblock against

the maxillary second molar. If the tooth of

interest is in contact with the biteblock, it is

rare to not capture the apices. Establishing

criteria for receptor placement will also help

diminish placement errors (e.g. center the

second molar on the biteblock for the molar

periapical projection).

Horizontal overlap

A major complaint about bitewing

radiographs is horizontal overlapping of

the interproximal contacts ( Figure 4 ). It

is very difcult to identify interproximal

caries if the contacts are overlapped. The

central ray must be aimed through the

contacts to capture an appropriate image.

For molar bitewings, the most difcult

contact to open is the maxillary rst and

second molar contact ( Figure 5 ). There is

an anatomic reason for this difculty. The

FIGRE 3: Periapical view with no apicesPeriapical view with no apices; Note the space between the edge of the image and the cusp tips of the teeth

FIGRE 4: Horizontal overlapHorizontal overlap in bitewing projection

FIGRE 5: Inadequate density/contrastOverlapped interproximal contact between the maxillary rstand second molars




contact between the maxillary molars often

has a different entry angle than the mandibular

molars. If the central ray is directed through

the mandibular molar contacts, the maxillary

molar contacts will be overlapped. If the central

ray is directed through the maxillary molar

contacts, the mandibular molar contacts will

be overlapped. Photons move in straight lines,

so it is not reasonable to think that photons

can change their course to open all the molar

contacts at the same time. The solution is

to look for the maxillary molar contact in

the premolar view. The entry angle for the

premolars is similar to that of the maxillary

molars.

Placement of the premolar bitewing can be

challenging when the patient’s dental arch is

square, or when rigid sensors are being used.

The receptor cannot be moved any farther

forward if it is already in contact with the

lingual surface of the mandible, so something

else has to give. The solution is to rotate the

receptor toward the anterior. It is difcult to

determine how far forward the receptor can

be placed without closing all of the premolar

contact. The problem is compounded when the

clinician rotates the receptor forward (with a

receptor holder with external guide, such as an

XCP instrument) and then aims the tube head

through the ring. The solution is to place the

receptor forward to capture the distal of the

canine and then direct the central ray through

the interproximal contacts ( Figure 6 ). The use

of bitewing tabs can also be a challenge when

rotating the receptor forward—the tab isn’t long

enough to stabilize placement. Placing a tab

on the existing tab will provide more length to

stabilize the receptor and provide a target for

aligning the tube-head.

FIGRE 6 Incorrect placementOffset Technique; 6a depicts the typical placement of a premolar

bitewing. The anterior border of the lm will not capture thedistal of the canine. 6b demonstrates moving the image receptormedially and rotating towards the anterior. 6c shows the typicalentry angle for the image (blue arrow) and the offset entry angledirected through the premolar contacts (red arrow)




Horizontal overlap also occurs with the canine periapical

projection. There is an expectation that both the mesial contact

and distal contact can be opened in the same view. The difference

between the entry angles for the mesial and distal contact is as

much as 45 degrees. Because of this angular difference, we should

look for the mesial contact in the canine view and the distal

contact in the premolar view.

Cone-cuts

It is hard to imagine that someone can cone-cut an image when

using external beam guides but not so with tab bitewings or

periapical views taken with an alternate holder such as a Snap-

a-ray™ ( Figure 7 ). Tab bitewings can present difculties when

the clinician can’t see the tab. Traditionally, the bitewing tab

has been centered on the receptor in both the horizontal andvertical dimensions. The target is in the middle of the receptor

and clinicians tend to overcompensate for what they can’t see—

anterior cone-cuts in the molar bitewings, posterior cone-cuts in

the premolar shot. A simple technique modication is to place the

tab on the anterior aspect of the receptor. Now the tab indicates

the anterior aspect of the receptor and a more visible target for

tube-head alignment.

Optimizing your panoramic image

Panoramic radiographs have become commonplace in the

practice of dentistry. Image quality has greatly improved since

the rst “Panorex” machine was introduced. Still, panoramic

technique is not without its challenges. The more common image

quality errors will be discussed.

Exposure errors

Since the image capture time cannot be adjusted with the

panoramic machine, other exposure parameters must be adjusted.

These parameters are contrast and density. Density is the overall

darkness in a radiographic image and is controlled by adjusting

milliamperage (mA). Contrast is the difference in density

visualized in the image. Contrast is controlled by kilovolt peak

(kVp). Most panoramic units provide exposure charts for average

sized patients. What about the patients who are not “average”

sized? How do you adjust for appropriate density and contrast?

FIGRE 7: Tab bitewingstab bitewings 7a demonstrates the typicalplacement of the tab on the imagereceptor—centered in the horizontal andvertical planes. 7b shows the tab placed

along the anterior border of the imagereceptor. 7c depicts placement of a secondtab on top of the existing tab to lengthenthe biting area.

7a

7b

7c




Kilovoltage provides the penetrating power of the X-ray beam. Kilovoltage must be

adjusted according to bone density. Kilovoltage should be increased for a patient

with large jaws. Milliamperage is adjusted according to the soft tissue content of

the patient: Lots of soft tissue increase the milliamperage; minimal soft tissues

decrease the milliamperage. The adjustment of exposure factors seems to affect

digital panoramic images more than lm based panoramic images. While digital

panoramic units provide an opportunity to enhance the image, it is important to

remember that you can lighten an image that is too dark but you can’t darken an

image that is too light. With light images, the information never made it to the

receptor; the purpwose of image enhancement is to make an acceptable image

better, not to change an inadequate image into an adequate image. Again, a good

way to determine if exposure factors are correct is to evaluate the dentin and

enamel of the maxillary molars. If enamel and dentin can’t be delineated, the image

does not have adequate density or contrast.

Patient positioning

The majority of errors seen in panoramic imaging are related to patient positioning.

The primary goal is to position the patient in the focal trough of the panoramic

machine. The focal trough is a horseshoe-shaped area in which structures will be

captured in focus. Focal trough dimensions are designed to capture images of the

average patient. This can be a challenge when the patient isn’t “average.”

The most important aspect of patient positioning is to ensure that the patient is

standing or sitting up straight. First have the patient stand next to the panoramic

machine and bring the chinrest up a little higher than the patient’s chin when

they are standing up straight; then guide the patient into the machine. This can

be difcult if the clinician is not as tall as the patient. The clinician needs to be

at eyelevel with the patient. If necessary, have a stool available for the operator

to stand on. If the chin rest is too high, it can

always be adjusted down; if the chin rest is too

low, the patient will adapt to its position and

bend down to place their chin on the chin rest

(Figure 8). This causes the patient’s neck to

shorten and pushes the spine posteriorly. The

risk here is that you may brush the patient with

the tube head as it circles the patient during

exposure. The brushing of the patients’ neck

or shoulders can produce a motion artifact

in the image or even stop the image process

completely. There are several patient types

FIGRE 8: Superimposed cervical spine; accentuatedpalatoglossal airspace. Panoramic Image with shadow of cervicalspine in the midline of the image. The palatoglossal airspace isaccentuated because the patient did not place tongue on the roof of the mouth.




who have difculty standing up straight. The rst group consists of individuals

taller than 6’ 4”. They are taller than the highest position for the chin rest. Asking

these patients to stoop down to the chin rest will result in the shoulder brushing

previously discussed. Have patients spread their feet as far apart as possible. This

adjustment may allow them to place their chin on the chin rest with an erect spine.

If spreading the feet apart doesn’t sufciently lower the patient’s chin, have the

patient sit in a chair and adjust the machine accordingly. The second patient type

with trouble standing up straight has a curved spine due to osteoporosis. Try as

they may, they can’t stand up straight. Have these patients sit in a chair and scoot

their legs forward so their spine is rotated vertically. This technique modication

may render the patient’s spine erect.

Next, adjust the chin position so the occlusal plane is approximately ve degrees

below parallel. This head position will generate a slight “smile” of the occlusal plane

in the image. If the occlusal plane is too high, the occlusal plane becomes a frown

rather than a smile. As the occlusal plane tilts more superiorly, the hard palate

becomes superimposed over the apices of the maxillary teeth, and the mandibular

condyles are projected off of the sides of the image (Figure 9).

FIGRE 9: Occlusal plane positioning error: Chin upThe occlusal plane is canted upward. The occlusal plane appears to be a reverse smile




If the occlusal plane is positioned inferiorly, the

smile becomes exaggerated; the condyles are

projected off of the top of the image and the

mandibular anterior teeth become distorted

due to their relationship with the focal trough

(Figure 10).

Once the occlusal plane is positioned, make sure

that the mid-sagittal plane is oriented verticalto the oor. Remember that mid-sagittal plane

traverses the head completely, so don’t just

adjust the head position by lining up on the

nose and or between the eyes. If the mid-sagittal

plane is not centered, one side of the panoramic image will be too big and the

other too small (Figure 11). The side toward which the head is twisted will appear

magnied because the structures are located behind the focal trough. The side

away from the head twist will appear smaller than the opposite side because the

structures are located in front of the focal trough. A good way to assess if the head is

twisted is to compare the last tooth in the arch that has a twin (i.e. compare the size

of the right third molar to the size of the left third molar). They should be the same

size. If the patient is edentulous compare the widths of the ascending rami. The

aforementioned errors occur when the head is twisted in the horizontal plane. The

head can also be twisted in the vertical plane.

FIGRE 11: Midsagittal plane positioning error: Horizontal head

twistThe midsagittal plane is not correctly aligned; the teeth on theright are smaller than normal; the teeth of the left are larger thannormal. The patients left side was positioned farther away from thereceptor than the right side.

FIGRE 10: Occlusal plane positioning error: Chin downThe occlusal plane is canted downward. The occlusal plane appears to be an exaggerated smile. The mandibular condyles are projected

beyond the top of the image.




FIGRE 12: Midsagittal plane positioning error: Vertical tiltThe midsagittal plane is not correctly aligned the patients headis tilted towards the left. The occlusal plane is altered and thecondylar heights are not in the same horizontal plane.

A vertical head tilt can be identied by an

uneven occlusal plane or uneven condylar heads

(Figure 12).

The nal positioning adjustment is to orient the

patient in the focal trough in the anteroposterior

(AP) dimension. Most machines provide a light

to help with this positioning. Generally the light

is lined up with the contact between maxillary

lateral incisor and canine. If the anterior teeth

are positioned in front of the focal trough, the

image of the anterior teeth will be distorted

in the vertical plane ( Figure 13 ). The teeth

appear long and skinny. If the anterior teeth are

positioned behind the focal trough, the teeth will be distorted in the horizontal plane ( Figure

14 ). What if the patient doesn’t have teeth? Line

up with the ala of the nose. Use of the extraoral

landmark will help position patients with

excessive anterior inclinations as well. Another

situation that impacts patient positioning in the

AP dimension is when malocclusion interferes

with the patient’s ability to bite end to end

on the bite stick. Many times clinicians will

attempt to split the difference and end up with

suboptimal imaging of the anterior teeth. Figure

out which arch is the most important and line

that arch up with the bite stick. For a general

overview of structures, lining up the mandibular

anterior teeth in the focal trough provides the

most imaging information.

Once the patient’s head has been positioned and stabilized, several instructions

must be given before beginning the exposure. Instructing the patient to put his or

her tongue on the roof of the mouth often results in an enlarged airspace because

the patient puts the tip of their tongue on the incisive papilla ( Figure 8 ). Asking the

patient to swallow and hold the tongue against the roof of the mouth will diminish

the size of the palatoglossal airspace. The patient is also asked to close his or her

lips around the bite stick. The soft tissues of the lips help to lter the X-ray beam

and diminish the burnout of the anterior teeth. Instructing the patient to close his

FIGRE 13: AP positioning error: Too far forward Anteroposterior plane positioning error. The patient is too farforward in the focal trough. The anterior teeth are stretchedvertically.

FIGRE 14: AP positioning error: Too far back Anteroposterior plane positioning error. The patient ispositioned behind the focal trough. The anterior teeth arestretched horizontally.




or her eyes will diminish the likelihood that the patient will move his or her head

in response to the movement of the tube head and carriage. Finally, the patient is

asked to hold still. Unfortunately, there are some patients who cannot follow the

instruction. Many of these patients are unsteady on their feet, and asking them to

close their eyes tends to make them even more unsteady. For these patients, placing

them in a chair will help control the movement.

The purpose of this article is to help the clinician optimize their radiographic

imaging. Slight modications in technique can make a large difference in the

quality of the radiographic image.






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