53660065 Rubinstein Mulitdiscplinary Approach to Single Tooth Replacement

A Multidisciplinary Approach to Single-Tooth Replacement

Sergio Rubinstein, DDS*Alan J. Nidetz, DDS*Masayuki Hoshi, RDT**

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ver the last several decades, dentistryhas focused on more conservative treat-ment modalities and preventive tech-

niques. This has been possible not only becauseof improved techniques and materials, but alsobecause of the understanding that tooth prepara-tion, regardless of how conservative it may be, isan irreversible procedure.

A missing tooth in the anterior region is notonly a physical loss, but also may be an emotionalexperience for the patient as well. To removehealthy tooth structure of adjacent teeth to re-place a congenitally missing tooth or a tooth lostto decay, trauma, root fracture, failed root canal

treatment, or pathology is, for some patients anddentists, a very aggressive treatment option. In-fection in any of these situations creates an envi-ronment in the hard and soft tissues that makesregeneration procedures more difficult, therebycomplicating the ability to create a natural ap-pearance in the definitive restoration.

While a conventional three-unit fixed partial den-ture is a predictable technique to replace a missingtooth, the invasive nature of the treatment can leadto other complications throughout the life of therestoration. Complications may include mechanicaloverload of the abutment teeth with weakening orfracture, risk of endodontic treatment, periodontalproblems, decay, and cement failure. If any of thesecomplications occurs on one of the abutmentteeth, the entire prosthesis will fail. Splinting teethcan overload the supporting structures becauseteeth function individually, and oral hygiene tech-niques become more cumbersome.

*Oral Rehabilitation Center, Skokie, Illinois, USA.**Oral Rehabilitation Institute, Skokie, Illinois, USA.Correspondence to: Dr Sergio Rubinstein, Oral RehabilitationCenter, 64 Old Orchard, Suite 420, Skokie, IL 60077, USA. E-mail: [email protected]

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HISTORY OF SINGLE-TOOTH RESTORATIONS

For more than 50 years, dentistry has sought amore conservative approach to replacing a singlemissing tooth with a conventional fixed prosthesis,which involves the cutting of sound tooth struc-ture. Treatment possibilities have evolved frombonding a natural extracted tooth or compositeresin restoration to the adjacent teeth,1–3 to theRochette bridge,4,5 to the Maryland bridge,6–8 andcurrently to the single-implant–supported crown.It is debatable which technique is the most con-servative, and in many instances the patient’s pref-erence dictates the restoration of choice. The clin-ician must also evaluate the advantages anddisadvantages of such techniques in order to pro-vide the patient with the best clinical result sincenot all patients should be treated with the samerestoration type or design.

While the Rochette bridge replaced the miss-ing tooth without any tooth preparation, it was, atbest, considered a temporary solution, and itsframework was designed with a gold substructureand hence resulted in a thick metal framework.Such restorations were designed with macrome-chanical retentions (Figs 1a to 1c) to lock the com-posite into the gold and through the bonded lin-gual surface. This technique met the patient’sconservative requirements of replacing the miss-ing tooth, even though it required the patient’scompliance not to overload the prosthesis duringmasticatory function and necessitated a modifiedflossing technique because of the splinted pros-thesis (Fig 1d).

Proven over the years through the achievementof acceptable clinical results, such resin-bondedprostheses continued to improve, and their evolu-tion led to the development of the Marylandbridge.6,7 For this technique, the tooth required aconservative preparation in the enamel only8 with agingival rest to create a definite seat. The prepara-tion design included an interproximal wraparoundto help prevent lingual displacement and to in-crease stability on a bondable surface area(enamel) with a solid, nonperforated, metal sub-

structure that could be as thin as 0.2 mm. Use of anon-noble metal alloy significantly increases themechanical retention of the etched framework andmore easily prevents degradation of the lutingresin in the oral cavity. Care must be exercised sothe framework does not involve the incisal third ofthe abutment teeth, since this could block translu-cency and result in a graying effect (Figs 2a to 2h).

While use of a resin-bonded retainer involves avery conservative technique and preparation ofthe enamel is minimal, the mechanical retentiveproperties of the prosthesis, by design, have awraparound effect of 180 degrees. Still, care mustbe exercised to prevent occlusal overload duringfunction.

Presently, the single-implant–supported crownis a predictable method of tooth replacement,and it has several improvements over resin-bonded prostheses: preparation of adjacent teethis not needed; the tooth replacement will functionindividually; a conventional oral hygiene tech-nique can be used; preservation and stimulationof existing bone and soft tissues occur, includingrecreation of the interproximal papillae; and sta-bility and function are improved because of theimplant supporting the crown.

While osseointegration around implants is awell-documented phenomenon, the implant de-signs will continue to undergo structural modifica-tions to fulfill the prosthetic requirements onefaces as the practice of dentistry evolves. Suchchanges include the transitions from the standard-diameter implant to wider-diameter implants;from the external-hexagon, antirotational deviceto the internal morse taper connections; and fromthe two-stage surgical approach to the now morefrequently used one-stage techniques that includeimmediate loading. These are just a few of thefactors that complicate the analysis of implant de-signs with respect to failure or success. The areaoften considered the most critical is the implant-abutment interface, and because of evolving de-signs, this is where dentistry may see some signifi-cant changes to obtain the best possible fit andimproved tissue response.


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Rochette Bridge

1a 1b 1c

2d 2e 2f

2g 2h

Maryland Bridge

1d

Fig 1a Lingual view of the waxup for the Rochette bridge.

Fig 1b Cast framework on the stone model.

Fig 1c Framework showing mechanical undercuts to lock the bonded pros-thesis.

Fig 1d Buccal view of the bonded Rochette bridge. (Prosthetics and labora-tory work by Alexander H. Chan, DDS.)

Figs 2a and 2b The maxillary right central incisor and supporting bonehave been lost as a result of trauma. The rotation of the left central incisorand the vertical bone loss required a multidisciplinary treatment approach.

Fig 2c A connective tissue graft wasplaced to correct the soft tissue de-fect, and orthodontics corrected therotation of the left central incisor.(Orthodontics by Sergio Rubinstein,DDS; surgery by Sergio Rubinsteinand Patrick J. Pierre, DDS; 1981.)

Fig 2d Lingual view of the Mary-land bridge. The incisal extensionrequired slight trimming to avoidblocking translucency.

Figs 2e and 2f Views of the Mary-land bridge replacing the maxillaryright central incisor.

Figs 2g and 2h Views of the pa-tient’s smile.

IMPLANT PROSTHODONTICS

Since the endosseous implant was introduced inthe United States, the prosthetic indications havegrown from the mandibular, fixed, bone-anchoredprosthesis to the single-tooth replacement.9–16

While many clinicians still resist the application ofendosseous implants, preferring the more tradi-tional restorations, one could argue the relativemorbidity of preparing the adjacent teeth for fixedpartial dentures compared with the two-stage,one-stage, or immediate-loading implant surgicaland prosthetic protocol. Clearly not only can im-plant prosthodontics offer excellent cosmetic out-comes, but it also allows for bone preservationand stimulation, and the restoration most closelyresembles an actual tooth during function.

DIAGNOSIS

When a patient needs replacement of a missingtooth (Figs 3a to 3c), the clinician must perform aseries of clinical and radiographic evaluations (Fig3d) to visualize and offer the available treatmentoptions. The patient must be made aware of theseoptions, which generally include some form of re-movable partial denture, resin-bonded retainers,fixed partial prosthesis, or an implant-supportedrestoration. If a single-tooth implant restoration isconsidered, the clinician must first determinewhether an adequate recipient bed, or site, for theimplant exists. Once this has been determinedclinically and radiographically, the function, esthet-ics, and contours of the final prosthesis, as well asperi-implant health, should be considered. Treat-ment should proceed only if all prerequisites arefulfilled. It is important that the site to be treatedbe evaluated along with the complete dentition toformulate a comprehensive treatment plan.

CLINICAL EXAMINATION

Definitive tooth replacement must follow activedisease control and some type of provisionaliza-

tion of the missing tooth (Fig 3e). Several clinicalconcerns need to be addressed: measurement ofinterproximal space and adjacent teeth, the oc-clusal relationships, anterior and canine guidance,and esthetic demands. The esthetic demands in-clude the lip profile, alveolar height and buccolin-gual dimensions, and the quality of the overlyinggingiva.9

There must also be enough mesiodistal clear-ance for the implant in order to avoid risk to adja-cent structures such as the nasopalatine ormandibular nerve, nasal cavity, neighboring teeth,or the maxillary sinus. In most cases, the implantand prosthetic components will require a mini-mum of 6 to 8 mm of mesiodistal clearance de-pending on the location in the dental arch.15–18 Acongenitally missing tooth will most likely have anormal osseous ridge, both in height and width,whereas alveolar atrophy always follows the ex-traction of teeth. Its severity depends on severalfactors, including (1) quantity and quality of bone,(2) existing or previous pathology, (3) length oftime following tooth loss, and (4) trauma incurredduring the extraction and the loading of the tis-sues. The collapse of the facial plate and alveolarheight subsequent to tooth loss19 can impact theposition and angulation of an implant. The idealimplant placement and how alternative positionsaffect prosthetic design and morphology hasbeen described at length; however, this will varyfrom case to case and depending on the implantsystem selected.

Occlusal relationships will influence the designof the crown. A minimum of 7 to 8 mm is requiredfrom the coronal aspect of the implant to the op-posing occlusion.15,16 When determining the occlusal clearance for an implant, it is important toremember that implants are often intentionallyplaced below the crest of the ridge about 2 to 4mm apical to the cementoenamel junction of adja-cent teeth to provide a sufficient emergence profilefor the crown.20 Incisal relationships that subjectteeth to heavy occlusal loads must be carefullyevaluated, because an esthetic result must beachieved while the teeth and implant are protectedfrom undesirable forces.21,22 While parafunctional

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Restoration of Lateral Incisors

Fig 3d Initial radiograph showing inadequate space to place implants in theposition of the congenitally missing lateral incisors.

Fig 3e Orthodontic treatment in progress with provisional prostheses bondedonly to the mesial of the canines while the root position of the central incisors isbeing adjusted. Once the centrals are in the correct position, the provisionalsare bonded to them while the position of the canines is adjusted. Treatmentcan then proceed to implant surgery. (Orthodontics by Howard Spector, DDS.)

Fig 3f Incisal view of premachined, 15-degree angulated abutments. Notethat the implants have been placed slightly palatal to the incisal edge so theabument screws can be placed in the cingulum area. (Surgery by Douglas V.Gorin, DDS.)

Fig 3g Acrylic resin, implant-supported, provisional restorations 4 monthsafter insertion. Soft tissue contouring and tooth bleaching have been accom-plished at this stage. 3d

3e 3f 3g

3h

3i 3j

Figs 3a to 3c Pretreatment views of Maryland bridges. The lateral incisor prostheses are improperly contoured be-cause of the malpositioned maxillary central incisors and canines.

Fig 3h Final crowns in solid stone model with soft tissue duplication.

Fig 3i Horizontal lingual screws allow for improved lingual contours andease of retrievability.

Fig 3j Final implant-supported crowns on the maxillary left and right lateralincisors. (Prosthetics by Sergio Rubinstein, DDS; laboratory work byMasayuki Hoshi, RDT.)

activities are not a contraindication for implants,they do influence treatment planning.23 It isparamount to have a passive fit between the im-plant, component(s), and crown.24–28

Because esthetic demands have an enormousimpact on the treatment planning of implant-sup-ported prostheses, a high lip position that exposesthe gingiva will affect the requirements of implant

placement, soft tissue management (Figs 4a to4d), and design of the final prosthesis. Loss of cre-stal bone requires a longer clinical crown usuallywith larger gingival embrasure spaces. A narrowimplant diameter placed into a site with minimalalveolar bone loss can lead to unesthetic resultswith improper contours, such as a bulky implant-prosthetic connection with a cantilever effect.

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Soft Tissue Management with a Fixed Provisional Restoration

Fig 4a The patient was unhappy with the esthetics ofthe maxillary right central incisor crown. Supereruptionof the tooth could have predictably corrected the gingi-val recession, but the patient declined the treatment.The prognosis was hopeless, and the tooth was ex-tracted.

Fig 4b Healing site showing gingival height discrep-ancy between the central incisors 7 days after tooth ex-traction. (Surgery by Leslie B. Heffez, DDS.)

Fig 4c Composite resin provisional restoration bondedin place. Even though the soft tissue discrepancy willhave to be corrected during second-stage surgery, notethe interproximal papillae preservation with the fixedprovisional.

Fig 4d Incisal view of the fixed bonded provisional.(Prosthetics by Sergio Rubinstein, DDS; laboratory workby Orly Farahmandpour.)

SOFT TISSUE CONSIDERATIONS

It is well-documented that soft tissue architectureis influenced by the underlying bony architec-ture.29–31 It is further documented that tooth lossresults in a loss of alveolar bone height and loss ofsoft tissue architecture in both the facial and api-cal directions.32 When a tooth must be extracted,changes in bone loss and soft tissue architecturecan be controlled by using orthodontic supererup-tion prior to extraction.3 This technique can pro-vide solutions to very difficult situations (Fig 5a).On average, anterior tooth loss will result in a 3-mm apical migration of the soft tissue. Supererup-tion of 3 mm prior to extraction will compensatefor this loss.33 When a defect in soft tissue archi-tecture already exists, it can be predictably cor-

rected by adding the amount of the defect in mil-limeters to the “3-mm rule.” For instance, a 3-mmdefect would require 6 mm of supereruption (Figs5b to 5d). After supereruption is complete, theclinician should wait 3 months before proceedingwith extraction and implant placement. This al-lows for complete maturation of both the boneand the soft tissue. Once the tooth is extractedand the implant is placed, an ovate pontic is usedto provide scaffolding for the soft tissue duringthe healing process34,35 (Figs 5e to 5l). The implantis uncovered, and an immediate provisionalrestoration engaging the implant is placed toallow for tissue maturation36 (Figs 5m to 5p). Thefinal prosthetic restoration is fabricated and deliv-ered after the hard and soft tissues have healed(Fig 5q).

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Soft Tissue Management with Supereruption

Fig 5a Preoperative photograph showing a 3-mm apical migration of the gingiva at the rightcentral incisor compared with that at the leftcentral incisor.

Fig 5b Orthodontic brackets positioned toachieve 6 mm of supereruption. (Orthodontics,restorative dentistry, and laboratory work byAlan J. Nidetz, DDS; surgery by David Barack,DDS.)

Fig 5c The labial root is torqued to bring thepalatal bone labially.

Fig 5d Supereruption is complete. Note theovercorrection of the gingival height.

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Soft Tissue Management with Supereruption (continued)

5i 5j

5k

5f 5g 5h

5e

5l

Fig 5e Radiograph taken immediately after implantplacement.

Figs 5f to 5h Fabrication of a fixed provisional Mary-land bridge.

Figs 5i and 5j The provisional Maryland bridge isplaced immediately following implant placement.

Figs 5k and 5l Clinical and radiographic views after 4months of healing.

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Fig 5m Appearance of the soft tissue immediatelyupon removal of the fixed provisional.

Figs 5o and 5p Tissue appearance 4 weeks after implant uncovering.

Fig 5q Final restoration. (Figs 5a to 5q: Orthodontics, restorative dentistry,and laboratory work by Alan J. Nidetz, DDS; surgery by David Barack, DDS.)

Fig 5n Tissue appearance immediately after implantuncovering and placement of the second provisional.

RADIOGRAPHIC EXAMINATION

Radiographs will provide information regardingthe bone available for implant placement and theposition of vital structures, as previously de-scribed, in order to help prevent disappointingpostoperative results. Determining the need forspecific radiographs depends to some degree onthe patient’s clinical presentation as well as thedental team’s philosophy.

Periapical radiographs will provide a fairly accu-rate assessment of interdental clearance (see Fig3d); however, maxillary anterior radiographs aresubject to frequent elongation as a result of filmangulation. Panoramic radiographs are also sub-ject to significant distortion both horizontally andvertically.37,38 As much as radiographic markers,such as metal balls of known dimensions, can helpto calibrate the films for improved accuracy, thelack of dimensional reliability combined with thetwo-dimensional quality of traditional radiographsunderscores the value of digital reformatted com-puterized tomography. These diagnostic films pro-vide a three-dimensional cross-sectional viewthrough the maxilla or mandible with a 1.1:1 or1:1 magnification ratio.38–40 Linear tomograms canbe useful for isolated areas while minimizing radi-ation and expense to the patient.41,42 This type oftomogram will clearly demonstrate the quality ofcortical and trabecular bone as well as the bound-aries of the facial or linguopalatal plate, the maxil-lary sinus, nasal cavity, and mandibular nerve.

Radiographic stents with radiopaque markerssuch as gutta-percha or barium sulfate can behelpful (Figs 6a and 6b). These will produce across-sectional image indicating the desired incli-nation of the implant with its possible correspond-ing contours. This position can then be evaluatedin terms of available bone to determine whetherthe desired position is surgically realistic. Clearly,the osseous architecture will not always allow forideal implant position. The information providedby cross-sectional images will enable the clinicianto anticipate any limitations and determine how tocorrect defects surgically or identify acceptable al-ternative implant positions. With careful planning,the surgeon and restorative dentist can eliminatewhat otherwise might be an unpleasant surpriseand then communicate to the patient possibleprosthetic designs as a function of the ultimateimplant position.

Once all the diagnostic data have been ob-tained, the surgeon and restorative dentist mustanticipate the design of the final restoration toachieve an optimum functional and esthetic clini-cal result. The final position of the implant de-pends not only on the hard and soft tissue topog-raphy, but also on the implant diameter, thedesired emergence profile, and the contours ofthe neighboring teeth. The simplest restorativedesign to date places the abutment screwthrough the cingulum in anterior teeth andthrough the central groove in posterior teeth. Toachieve this result, the surgeon must position the

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Radiographic Stents

Figs 6a and 6b Radiographic and surgical stent with barium sulfate to delineate buccal contours. Gutta-perchamarkers are placed on the occlusal surface to suggest the ideal implant inclination.

implant slightly palatal to the incisal edge for an-terior teeth and close to the central groove forposterior teeth. If the surgeon and restorativedentist determine that a facial angulation is re-quired, then some form of substructure, such as apremachined angled abutment (see Fig 3f) or cus-tom abutment, will be necessary to maintain anesthetic result.

STENT CONSTRUCTION

Once the initial clinical and radiographic findingshave been established, a clear acrylic resin orplastic stent with radiographic markers should befabricated. Such a stent should demonstrate theideal prosthetic position and indicate the pre-ferred implant placement as well as acceptable al-ternatives that will facilitate an optimum final pros-thesis.

Clinicians may be tempted to place implantsfor single-tooth replacements without a stent, be-lieving that the neighboring teeth will serve as areference for implant inclination and position.However, once the flap has been raised, the sur-geon will focus on the osseous architecture to de-termine optimum implant support. The stent canserve to prevent prosthetic failures resulting fromoverangulation, especially to the facial. Generally,the stent used for preoperative radiographs canalso be used during surgery to guide implantplacement and to help in uncovering the implantafter the primary healing period.

Stents used for single-tooth replacement aresimple in design and easy to fabricate. A stentthat replicates the buccal profile with the palatalportion cut out will prevent screw access to the fa-cial and will aid in centering the implant mesiodis-tally.43 Some clinicians prefer stents that restrictthe implant placement to a specific position (usinga 2- to 3-mm hole in the stent), as this will clearlyindicate the desired position for the primary drill.Once the surgeon increases the bur size, this stentis no longer usable. It is possible for the surgeonto slightly redirect bur angulation (especially insofter bone), but it does not allow for alternative

positions or angulations that may be clinically ac-ceptable. Alternatively, the stent should be en-tirely open in its lingual aspect to facilitate the sur-geon with additional options.

When stents are created, the radiographic stentcan be designed first, and if necessary it can bemodified to correspond to the computerized to-mogram. Such computerized tomogram–assistedstents will help to place the implant not only in itsplanned buccolingual and mesiodistal positions,but also at the desired depth.

PROVISIONALIZATION

The patient will want to wear some form of provi-sional tooth replacement during the primary heal-ing period, especially in an esthetic area. Primaryhealing can range from 2 to 8 months dependingon the clinical situation. The type of provisionalselected can be a removable appliance; a resin-bonded fixed provisional, if adjacent teeth allowfor bonding; or a passive acrylic resin provisionalusing the implant, with the restoration being outof occlusion. The advantages of the resin-bondedprovisional are that it is cosmetic, noninvasive,and fixed; it maintains occlusion and adjacentteeth positions; and it allows for tissue contouringand papillae preservation.

It is important that the appliance does nottransmit any load to the healing implant site andthus increase the risk of failure. The provisionalrestoration must maintain a passive fit and providefor soft tissue support.

SURGICAL PLACEMENT OF IMPLANTS

While placing the implant, the surgeon will focuson avoiding injury to vital structures or adjacentteeth, maximizing bony support for the implant,engaging cortical bone for implant stability (forcertain systems), and placing the implant in theideal prosthetic position. These considerationsmust be factored into planning the direction ofthe implant placement, the chosen length and di-

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ameter of implant to be used, the depth of im-plant placement (including whether the implantmust be countersunk, for some systems), theheight relative to the osseous crest and adjacentteeth, and whether or not bone grafting is to beimplemented.

A position that is centered between the neigh-boring teeth, with note to the anatomic struc-tures, usually best fulfills these considerations.The buccolingual orientation depends on thepresence of intact bone and the ability to engagethe palatal or buccal plate, while keeping in mindthe desired prosthetic position of the implant. Ifthere is a conflict between the most stable posi-tion of the implant and the desired prosthetic po-sition, then the surgeon must refer to the rangeof alternative acceptable positions. Some sur-geons will intentionally engage the floor of themaxillary sinus or nasal cavity, but care must betaken not to perforate these vital structures be-cause the predictability of osseointegration willbe diminished.44 The vertical position of the im-plant will depend on the desired emergence pro-file of the final crown. It has been recommendedthat the implant be placed 3 to 4 mm apical tothe neighboring cementoenamel junction.9,20 Ifminimal resorption of the osseous crest has oc-curred, the crest may require some resection tocreate the required space for countersinking theimplant to the suggested depth. Any resectionshould be postponed until the implant is uncov-ered to prevent excessive resorption of the crestand subsequent exposure of the implant surface.A wider implant diameter or narrower diameter ofthe tooth to be replaced can reduce the amountof countersinking needed to account for properemergence profile.20,45

The indications for osseous grafting includeaugmentation of the ridge for implant stability oresthetic concerns. Bone grafting may be per-formed, in some instances, 3 to 6 months beforeimplant placement. In selective cases, osseousgrafting can be performed at the time of implantplacement. If minor bone modification is needed,the osteotome can help stretch the existing bone.While ridge augmentation procedures have been

employed for several years,38 the predictability ofcrestal augmentation in the coronal direction isquestionable.46

OSTEODISTRACTION AND BONE GRAFTING

According to Samchukov et al,47 “Most significantnew ideas, concepts, or products go through afour-stage evolution in their infancy. They are ini-tially rejected by almost all potential users whoclaim that it cannot be done or it is too much trou-ble. Shortly thereafter, it is accepted by a few; thevast majority, however, contend that it is just notthere yet or maybe later. After a period of time,most people adopt the new technique, and beginto question why their colleagues are not using it.Finally, after years of clinical and experimentaldocumentation, it becomes the standard ofcare—the technique by which all others are com-pared.”

Osteodistraction has many clinical applicationsand facilitates different treatment modalities in amore conservative and predictable manner. Asdistractors become smaller and more efficient,distraction osteogenesis is becoming a viabletechnique to build up bone in a vertical direction.However, guided tissue regeneration techniqueshave improved the predictability for increasing theridge thickness, especially in smaller areas48–53 (Figs7a to 7d). Sinus lift procedures are currently beingperformed with a high degree of predictabilityand are enabling treatment options that oncewere not imaginable. It is important to rememberthat smoking has been shown to increase the rateof dental implant failure.54

Presently, the choice of osseous grafting mate-rials includes autologous bone, freeze-dried boneallograft, demineralized freeze-dried bone allo-graft, resorbable bone substitutes, and nonre-sorbable bone alloplast. Allografts can be placedinto fresh extraction sites and then covered withmembranes for guided tissue regeneration to pre-serve ridge height prior to the implantplacement.48 Researchers do not agree on theideal grafting material to be used around en-

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dosseous implants.55–60 Many clinicians prefer de-mineralized freeze-dried bone allografts in thetreatment of infrabony periodontal defects. How-ever, this grafting material appears to be subjectto rapid resorption when used in sites not rich inmesenchymal cells58; therefore, the use of richplasma cells mixed with autogenous bone is in-creasing in popularity. In time researchers will beable to evaluate its long-term stability. While bonegrowth into grafted sites has been reported,59,61 a

fibrous connective tissue around grafted hydrox-yapatite has also been documented.55 If graftedsites are infected, there may be a chance for theinfection to disseminate.61 Autogenous bone iswidely used, but volume may be limited by avail-able donor sites. A variety of materials have beenused with implant placement, but they appear tobe most predictable when used with membranesfor guided tissue regeneration.48,49,51,52

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Bone Grafting

Fig 7a The patient was unhappy with theMaryland bridge because of the need to flosslaterally with a threader. The patient was notinterested in correcting the malposition of thecanine with orthodontics.

Fig 7b The maxillary lateral incisor was con-genitally missing. Note the loss of the buccalplate, complicating ideal implant placement. Abone graft was required.

Fig 7c Final implant-supported crown. Fig 7d Lingual view of the final crown with ahorizontal screw, which improves the lingualcontour and ease of retrievability. (Prostheticsby Sergio Rubinstein, DDS; laboratory work byMasayuki Hoshi, RDT.)

TOOTH EXTRACTION WITH IMMEDIATEIMPLANT PLACEMENT

Implants can be placed into fresh extraction siteswhen adequate bone exists to immobilize the im-plant62–67; this generally requires that about 40% ofthe implant be embedded in firm bone tissue.Some benefits are improved preservation of alve-olar bone and decreased treatment time. Implantsshould not be placed into sites where there is in-adequate bone to stabilize the implant; to do sowill risk micromovement of the implant and inter-fere with the tissue’s ability to integrate aroundthe implant.16 Implants should also not be placedinto sites with a remaining infection associatedwith a diseased tooth. This would interfere withtissue healing, risking dissemination of the infec-tion as well as implant failure.68

For placement of an implant into a fresh ex-traction site, the implant site should be preparedbeyond the apex of the extraction site and quiteoften along an axis not parallel to the long axis ofthe extracted tooth (Figs 8a to 8f). The coronalaspect of the implant will be either partially orcompletely exposed without direct contact to thesocket walls. Therefore, the cells of the bone tis-sue must travel a significant distance to reach theimplant surface and mature into a supporting tis-sue. This is in contrast to the surgical principlesdescribed in which a tight bone fit was consid-ered critical for osseointegration to occur.69 To en-courage bone fill of the remaining socket space,steps must be taken to prevent the gingival flapfrom contributing to the healing of this potentialspace.

One way to reduce the distance the bone cellsmust travel is to place an implant that resemblesthe anatomy of the extraction site, either conicalor cylindrical in shape. The implant will thus fillmore of the socket or be slighter larger to engagehealthy bone for its stability.

A bone graft will act as scaffolding for thebone-forming cells to travel and reach the implantsurface. Graft materials also support the flap andmay act as a barrier to the soft tissue. Expandedpolytetrafluoroethylene membranes used for

guided tissue regeneration also support the over-lying flap and thereby preserve the space to beoccupied by bone.62,64,66–68,70

One- and Two-Stage Surgery

In selective cases, second-stage surgery is notneeded when a taller healing cap is placed, thuspreventing the soft tissue from covering the im-plant. Such cases will depend on ease of the surgi-cal technique, occlusion, oral hygiene, and the pa-tient’s ability to follow postoperative instructions.

For other cases second-stage surgery is re-quired. The time allotted for the primary healingperiod depends on the site of implant placement,the quality of bone, whether bone grafting hasbeen performed, or whether the implant has beenplaced into a fresh extraction site. Generally, thisranges from 2 months71 to 8 months. At the time ofimplant uncovering osseointegration must be veri-fied by radiographic and clinical means.

Implant Uncovery

The desired esthetic result will influence soft tis-sue management during all surgical phases aswell as during implant uncovering72 (see Figs 3g to3j). Posterior implants are frequently uncovered byuse of linear incisions or a circular tissue punch.Anterior procedures should focus on the preserva-tion of keratinized tissue, color match of the gin-giva, and the ultimate height of the soft tissue fa-cial and interproximal to the implant. The need fora wide zone of keratinized tissue around implantshas been argued for some time. While manyagree that minimal to no attached tissue is neces-sary to maintain peri-implant health,73 estheticsdemands a healthy, wide zone of gingival tissuearound natural teeth and implants. If an inade-quate zone of tissue exists prior to implant place-ment, soft tissue grafting can be performed priorto placement of the implant. However, eitherpedical flaps or connective tissue grafts are pre-ferred because these procedures tend to providethe best color match of grafts to the recipient tis-sues.

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Follow-up care should include suture removal ifa flap was raised, plaque control, and evaluation ofhealing prior to initiation of prosthetic procedures.Oral hygiene with a soft brushing technique be-

gins when the healing cap is exposed into the oralcavity and will continue throughout treatment untilafter the implant-supported crown is in place. Oralrinses for plaque control have been shown to pro-

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Immediate Implant Placement

8c 8d

Fig 8c Radiograph showing impression post–implanttransition. Note the bone loss around the neck of theimplant subsequent to a previous infection.

Fig 8d Angled, screw-retained abutment with perfora-tion to accept a lingual screw.

Fig 8a Healing cap over the implant. The tooth was lostas a result of vertical fracture, and a fixed provisionalwas not used. Note the loss of the papillae.

Fig 8b Tissue healing around the implant. (Surgery byKenneth H. Peskin, DDS.)

Fig 8e Buccal view of the final crown. Fig 8f Lingual view of the final crown with the lingualscrew parallel to the axis of the implant. (Prosthetics bySergio Rubinstein, DDS; laboratory work by MasayukiHoshi, RDT.)

mote healing in the early postoperative period; in-definite use of chlorhexidine is typically prescribedas part of the oral hygiene regimen for implants. A3-month maintenance program has been shown toeffectively maintain peri-implant health.74 The sur-geon’s responsibility for the health of the implantdoes not end with second-stage surgery, but joinswith the patient’s and the restorative dentist’s ef-forts for a long-term successful result.

PROSTHODONTIC ALTERNATIVES

For many clinicians, fabrication of an implant-sup-ported crown as either a screw-retained or ce-mented restoration is a personal preference. Eachtechnique has its advantages and disadvantages.The screw-retained restoration allows more simpleretrieval if any modifications, repairs, or alterationsto the existing tooth contours or adjacent teeth areneeded. While traditionally the screw will be in avertical direction along the axis of the implant, ahorizontal or transversal placement of the screw inthe lingual surface of an anterior restoration will

allow for better lingual anatomy on its lingual sur-face along with the improved esthetics (see Fig 7d).

Another option is to have the abutment screwretained on the implant with the final restorationtemporarily cemented to the abutment to allowfor some retrievability. However, in some cases re-trievability of a temporarily cemented crown canbe a challenge. An additional problem can occurwhen the crown is permanently cemented andthere is uncertainty of whether the cement hasbeen removed entirely. Two of the most favorableadvantages of the cementable crown are its simi-larity to conventional prosthodontics and the elim-ination of the screw through the crown, hencebetter contours and esthetics (Figs 9a to 9d).

Designs of implant restorations have evolved toaccommodate the width of the different teeththey can replace, not only wider anterior teeth butalso posterior teeth (Figs 10a to 10f). With the ex-isting variations of teeth and the mesiodistalspace between teeth in direct correlation to theavailable supporting bone, it is necessary to haveimplants of different diameters to solve the chal-lenges faced in implant dentistry.

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Implant-Supported, Cemented Crown

9a

9d

9b 9c

Fig 9a Incisal view of a screw-retained abutment.

Fig 9b Buccal view of an implant-supported, permanently cemented crownon the maxillary right lateral incisor.

Fig 9c Lingual view of an implant-supported, permanently cemented crown.

Fig 9d The maxillary right lateral incisor crown looks natural in the patient’ssmile. (Prosthetics by Sergio Rubinstein, DDS; surgery by Robert A. Bress-man, DDS; laboratory work by Masayuki Hoshi, RDT.)

CONCLUSION

The ultimate goal of the single-tooth implantrestoration is to restore the lost tooth with bothoptimum function and esthetics. The definitiverestoration should ideally resemble the originaltooth in contour and shade while both restoringand preserving the bone and soft tissues. Long-term health will only be possible if treatment isfollowed by a proper maintenance program.

ACKNOWLEDGMENTS

We would like to thank Dr Tatiana Quintiliano for her tirelesseffort in helping us prepare this article for publication.

REFERENCES

1. Ibsen RL. One-appointment technic using an adhesivecomposite. Dent Surv 1973;49:30–32.

2. Ibsen RL. Fixed prosthetics with a natural crown ponticusing an adhesive composite: Case history. J South CalDent Assoc 1973;41:100–102.

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Fig 10a Occlusal view of a customized abutment, with interproximal grooves, milled at 2 degrees of convergence.

Fig 10b Lingual view of the abutment with mesiolingual tapping to allow for a screw-retained crown.

Fig 10c Porcelain-fused-to-metal crown retained with a lingual screw. Note the narrow buccolingual contours tominimize undesirable occlusal loads.

Fig 10d Lingual view of final crown.

Fig 10e Buccal view of final crown.

Fig 10f Radiograph of final crown. While a mesial cantilever is present, it is diminished by the use of the widestavailable implant. (Prosthetics by Sergio Rubinstein, DDS; surgery by Jeffrey K. Bressman, DDS; laboratory work byToshiyuki Fujiki, RDT.)

Posterior Single-Tooth Restoration

10a 10b 10c

10d 10e 10f

3. Jordan RE, Suzuki M, Sills PS, Gratton DR, Gwinnett JA.Temporary fixed partial dentures fabricated by means of theacid-etch resin technique: A report of 86 cases followed forup to three years. J Am Dent Assoc 1978;96:994–1001.

4. Rochette AL. Attachment of a splint to enamel of loweranterior teeth. J Prosthet Dent 1973;30:418–423.

5. Howe DF, Denehy GE. Anterior fixed partial dentures uti-lizing the acid-etch technique and a cast metal frame-work. J Prosthet Dent 1977;37:28–31.

6. Livaditis GJ, Thompson VP. Etched castings: An improvedretentive mechanism for resin-bonded retainers. J Pros-thet Dent 1982;47:52–58.

7. Simonsen R, Thompson V, Barrack G. Etched Cast Restora-tions: Clinical and Laboratory Techniques. Chicago:Quintessence, 1983.

8. Rubinstein S, Jekkals V. Preparation for anterior resin-bondedretainers. Compend Cont Educ Dent 1986;7:631–632.

9. Parel SM, Sullivan DY. Esthetics and Osseointegration.Dallas: Osseointegration Seminars, 1989.

10. Ohrnell L-O, Hirsch J, Ericsson I, Brånemark P-I. Single-tooth rehabilitation using osseointegration. A modifiedsurgical and prosthodontic approach. Quintessence Int1988;19:871–876.

11. Lewis SG, Beumer J III, Perri GR, Hornburg WP. Single-tooth implant restorations. Int J Oral Maxillofac Implants1988;3:25–30.

12. Jemt T, Lekholm U, Grondahl K. A 3-year follow-up studyof early single implant restoration ad modum Brånemark.Int J Oral Maxillofac Implants 1990;5:341–349.

13. Andersson B, Odman P, Carlsson L, Brånemark P-I. A newBrånemark single-tooth abutment: Handling and earlyclinical experiences. Int J Oral Maxillofac Implants1992;7:105–111.

14. Weiner RE. A comparison of the UCLA abutment to theCera-One technique [abstract from the 7th annual meetingof the Academy of Osseointegration, February 1992]. IntJ Oral Maxillofac Implants 1992;7:126.

15. Interpore IMZ Technique Manual, Revision 3. Irvine, CA:Interpore International, 1987.

16. Hobo S, Ichida E, Garcia LT. Osseointegration and OcclusalRehabilitation. Chicago: Quintessence, 1990:105–132.

17. Priest GF. Single-tooth implants and their role in preserv-ing remaining teeth: A 10-year survival study. Int J OralMaxillofac Implants 1999;14:181–188.

18. Priest GF. Failure rates of restorations for single-tooth re-placement. Int J Prosthodont 1996;9:38–45.

19. Atwood DA. Bone loss of edentulous alveolar ridges. JPeriodontol 1979;50(4 special no):11–21.

20. Saadoun AP, Le Gall MG. Periodontal implications in im-plant treatment planning for aesthetic results. Pract Peri-odontics Aesthet Dent 1998;10:655–666.

21. Graf H. Bruxism. Dent Clin North Am 1969;13:659–665.22. Hobo S, Ichida E, Garcia LT. Osseointegration and Occlusal

Rehabilitation. Chicago: Quintessence, 1990:257–259.23. Ramfjord SP, Ash MM. Occlusion, ed 2. Philadelphia:

Saunders, 1971:99–140.24. Brånemark P-I, Zarb GA, Albrektsson T. Tissue-Integrated

Prostheses. Osseointegration in Clinical Dentistry.Chicago: Quintessence, 1985.

25. Zarb GA, Symington JM. Osseointegrated dental im-plants: Preliminary report on a replication study. J Pros-thet Dent 1983;50:271– 276.

26. Laney WR, Tolman DE, Keller EE, Desjardins RP, VanRoekel NB, Brånemark P-I. Dental Implants: Tissue-Inte-grated Prosthesis Utilizing the Osseointegration Concept.Mayo Clin Proc 1986;61:91–97.

27. Worthington P, Bolender CL, Taylor TD. The Swedish sys-tem of osseointegrated implants: Problems and complica-tions encountered during a 4-year trial period. Int J OralMaxillofac Implants 1987;2:77–84.

28. Sones AD. Complications with osseointegrated implants.J Prosthet Dent 1989;62:581–585.

29. Gargiulo AW, Wentz FM, Orban B. Dimensions and rela-tions of the dentogingival junction in humans. J Periodon-tol 1961;31:6261–6267.

30. Vacek JS, Gher ME, Assad DA, Richardson AC, Giambar-resi LI. The dimensions of human dentogingival junction.Int J Periodontics Restorative Dent 1994;14:154–165.

31. Becker W, Ochsenbein C, Tibbetts L, Becker BE. Alveolarbone anatomic profiles as measured from dry skulls. Clini-cal ramifications. J Clin Periodontol 1997;24:727–731.

32. Kois JC. Esthetic extraction site development: The geologicvariables. Contemp Esthet Restorative Pract 1998;2:10–18.

33. Salama H, Salama M. The role of orthodontic extrusive re-modeling in the enhancement of soft and hard tissue pro-files prior to implant placement: A systematic approach tothe management of extraction site defects. Int J Peri-odontics Restorative Dent 1993;13:312–333.

34. Kan JY, Rungcharassaeng K. Site development for ante-rior single implant esthetics: The dentulous site. Com-pend Contin Educ Dent 2001;22:221–232.

35. Spear FM. Maintenance of the interdental papilla follow-ing anterior tooth removal. Pract Periodontics AesthetDent 1999;11:21–28.

36. Jemt T. Restoring the gingival contour by means of provi-sional resin crowns after single-implant treatment. Int JPeriodontics Restorative Dent 1999;19:21–29.

37. Klinge B, Petersson A, Maly P. Location of the mandibularcanal: Comparison of macroscopic findings, conventionalradiography, and computed tomography. Int J Oral Max-illofac Implants 1989;4:327–332.

38. McGivney GP, Houghton V, Strandt JA, Eichholz JE, LubarDM. A comparison of computer-assisted and data-gather-ing modalities in prosthodontics. Int J Oral Maxillofac Im-plants 1986;1:55–68.

39. Schwarz MS, Rothman SLG, Rhodes ML, Chafetz N. Com-puted tomography, Part I: Preoperative assessment of themandible for endosseous implant surgery. Int J Oral Max-illofac Implants 1987;2:137–141.

40. Schwarz MS, Rothman SLG, Rhodes ML, Chafetz N. Com-puted tomography, Part II: Preoperative assessment ofthe maxilla for endosseous implant surgery. Int J OralMaxillofac Implants 1987;2:143–148.

41. Lindh C, Petersson A. Radiologic examination for locationof the mandibular canal: A comparison between panoramicradiography and conventional tomography. Int J Oral Max-illofac Implants 1989;4:249–253.

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RUBINSTEIN ET AL

42. Clark DE, Danforth RA, Barnes RW, Burtch ML. Radiationabsorbed from dental implant radiography: A comparisonof linear tomography, CT scan, and panoramic and intra-oral techniques. J Oral Implantol 1990;16:156–164.

43. Parel SM, Funk JJ. The use and fabrication of a self-retain-ing surgical guide for controlled implant placement: A tech-nical note. Int J Oral Maxillofac Implants 1991;6:207–210.

44. Brånemark P-I, Adell R, Albrektsson T, Lekholm U, LindstromJ, Rockler B. An experimental and clinical study of osseoin-tegrated implants penetrating the nasal cavity and the max-illary sinus. J Oral Maxillofac Surg 1984;42:497–505.

45. Jensen OT, Brownd C, DeLorimier J. Esthetic maxillaryarch vertical location for the osseointegrated cylinder im-plant. J Am Dent Assoc 1989;119:735–736.

46. Santoro F, Maiorana C, Rabagliati MI. Long-term resultswith autogenous onlay grafts in maxillary and mandibularatrophy. J Long-Term Eff Med Implants 1999;9:215–222.

47. Samchukov ML, Cope JB, Cherkashin AM. CraniofacialDistraction Osteogenesis. St Louis: Mosby, 2001.

48. Seibert J, Nyman S. Localized ridge augmentation indogs: A pilot study using membranes and hydroxyapatite.J Periodontol 1990;61:157–165.

49. Becker W, Becker BE, Handlesman M, et al. Bone forma-tion at dehisced dental implant sites treated with implantaugmentation material: A pilot study in dogs. Int J Peri-odontics Restorative Dent 1990;10:93–101.

50. Nyman S, Lang NP, Buser D, Bragger U. Bone regenera-tion adjacent to titanium dental implants using guided tis-sue regeneration: Report of two cases. Int J Oral Maxillo-fac Implants 1990;5:9–14.

51. Wachtel HC, Langford A, Bernimoulin JP, Reichert P. Guidedbone regeneration next to osseointegrated implants in hu-mans. Int J Oral Maxillofac Implants 1991;6:127–135.

52. Zablotsky M, Meffert RM, Caudill R, Evans G. Histologicaland clinical comparisons of guided tissue regeneration ondehisced hydroxyapatite-coated and titanium endosseousimplant surfaces: A pilot study. Int J Oral Maxillofac Im-plants 1991;6:294–303.

53. Mentag PJ, Kosinski T. Hydroxyapatite-augmented sitesas receptors for replacement implants. J Oral Implantol1989;15:114–123.

54. Bain CA. Effects of smoking on failure rates of dental im-plants [abstract from the 7th annual meeting of theAcademy of Osseointegration, February 1992]. Int J OralMaxillofac Implants 1992;7:123.

55. Kramer G, Mattout P, Mattout C, Mellonig JT. Clinical andhistological responses to a mixed bone/hydroxyapatitegraft: Report of a case. Int J Periodontics RestorativeDent 1989;9:9–21.

56. Aspenberg P, Kalebo P, Albrektsson T. Rapid bone healingdelayed by bone matrix implantation. Int J Oral Maxillo-fac Implants 1988;3:123–127.

57. Hoen MM, Strittmatter EJ, LaBounty GL, Keller DI, Ne-speca JA. Preserving the maxillary alveolar ridge contourusing hydroxyapatite. J Am Dent Assoc 1989;118:739–741.

58. Toriumi DM, Larrabee WF, Walike JW, Millay DJ, EiseleDW. Demineralized bone. Arch Otolaryngol Head NeckSurg 1990;116:676–680.

59. Hjorting-Hansen E, Worsaa N, Lemons JE. Histologic re-sponse after implantation of porous hydroxyapatite ceramicin humans. Int J Oral Maxillofac Implants 1990;5:255–263.

60. Holden CM, Bernard G. Ultrastructure in vitro characteri-zation of a porous hydroxyapatite/bone cell interface. JOral Implantol 1990;16:86–95.

61. Marshall SG. The combined use of endosseous dental im-plants and collagen/hydroxyapatite augmentation proce-dures for reconstruction/augmentation of the edentulousand atrophic mandible. A preliminary report. Oral SurgOral Med Oral Pathol 1989;68:517–526.

62. Lazzara RJ. Immediate implant placement into extractionsites. Int J Periodontics Restorative Dent 1989;9:333–342.

63. Ashman A. An immediate tooth root replacement. An im-plant cylinder and synthetic bone combination. J Oral Im-plantol 1990;16:28–38.

64. Becker W, Becker BE. Guided tissue regeneration for im-plants placed into extraction sockets and for implant de-hiscences: Surgical techniques and case reports. Int J Pe-riodontics Restorative Dent 1990;10:377–391.

65. Barzilay I, Graser GN, Iranpour B, Natiella JR. Immediateimplantation of a pure titanium implant into an extractionsocket: Report of a pilot procedure. Int J Oral MaxillofacImplants 1991;6:277–284.

66. Caudill RF, Meffert RM. Histologic analysis of the osseointe-gration of endosseous implants in simulated extraction sock-ets with and without E-PTFE barriers. Part I. Preliminary find-ings. Int J Periodontics Restorative Dent 1991;11:207–215.

67. Becker W, Becker BE, Handelsman M, Ochsenbein C, Al-brektsson T. Guided tissue regeneration for implantsplaced into extraction sockets: A study in dogs. J Peri-odontol 1991;62:703–709.

68. Simion M, Baldoni M, Polcan M. Effectiveness of GTAMmembranes with and without early exposure: A compara-tive study [abstract from the 7th annual meeting of theAcademy of Osseointegration, February 1992]. Int J OralMaxillofac Implants 1992;7:121.

69. Carlsson L, Rostkund T, Albrektsson B, Albrektsson T. Im-plant fixation improved by close fit. Acta Orthop Scand1988;59:272–275.

70. Hurzeler MB, Quinones CR. Installation of endosseousoral implants with guided tissue regeneration. Pract Peri-odontics Aesthet Dent 1991;3:21–29.

71. Lazzara RJ, Porter SS, Testori T, Galante J, Zetterqvist L. Aprospective multicenter study evaluating loading of Os-seotite implants two months after placement: One-yearresults. J Esthet Dent 1998;10:280–289.

72. Palacci P. Optimal Implant Positioning and Soft Tissue Man-agement for the Brånemark System. Chicago: Quintessence,1995.

73. Krekeler G, Schilli W, Diemer J. Should the exit of the arti-ficial abutment tooth be positioned in the region of theattached gingiva? Int J Oral Surg 1985;14:504–508.

74. Flemming TF, Berwick RHF, Newman MG, et al. Effect of a3-month maintenance program on osseointegrated im-plants. Microbiological observations. Z Zahnarztl Implan-tol 1990;6:45–51.

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53660065 Rubinstein Mulitdiscplinary Approach to Single Tooth Replacement

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