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DENTAL IMPLANT CLINICAL INNOVATIONS

Oral Maxillofac Surg2:2-16, 2004, Suppl 2

Fixed Partial Denture or Single-ToothImplant Restoration? StatisticalConsiderations for Sequencing

and TreatmentThomas J. Salinas, DDS,* Michael S. Block, DMD,† and Avishai Sadan, DMD‡

The choice to replace a single missing tooth can be based on the primary decision that the restorabilityof the tooth is in doubt. Many teeth are decimated by incipient or recurrent caries, trauma, endodonticcomplications, or periodontal disease which requires extraction. It is our objective to familiarize theparticipant with literature comparing success rates of fixed partial dentures and single-tooth implantrestorations and a repertoire of prosthodontic techniques used in replacement of single missing teethwith osseointegrated dental implants. The fixed partial denture (FPD) has been regarded as the standardof care for some time in replacement of single and multiple missing teeth. Many studies surveying longterm survival have been compiled and analyzed to arrive at a generalized outcome. Most of these studiesarrive at common conclusions. Studies surveying success of single-tooth implant-supported restorationsare not comparably abundant nor survey for comparable time as those for FPDs. Although, many of theoutcomes are statistical survival estimates such as Kaplan-Meier survival tables, implant restorations inpartially dentate patients are a predictable means of tooth replacement. There are certain factors whichmake FPD more appropriate and conversely factors which make an implant restoration more appropri-ate. Indications and contraindications for each treatment scenario will also be reviewed based on theliterature and clinical experience. It is hoped that the practitioner will be able to appropriately identifythose cases in which either an FPD or an implant restoration is the appropriate treatment option.© 2004 American Association of Oral and Maxillofacial SurgeonsJ Oral Maxillofac Surg 62:2-16, 2004, Suppl 2

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he choice to replace a single missing tooth can beased on the primary decision that the restorability ofhe tooth is in doubt. Many teeth are decimated byncipient or recurrent caries (Fig 1), trauma (Fig 2),ndodontic complications (Fig 3), or periodontal dis-ase that requires extraction. It is not the scope of this

*Assistant Professor, Department of Otolaryngology, The Univer-

ity of Nebraska Medical Center, Omaha, NE.

†Professor, Department of Oral and Maxillofacial Surgery, Loui-

iana State University Health Science Center, School of Dentistry,

ew Orleans, LA.

‡Associate Professor and Chairman, Department for the Practice

f General Dentistry, School of Dental Medicine, Case University,

leveland, OH.

Address correspondence and reprint requests to Dr Salinas:

epartment of Otolaryngology, The University of Nebraska Medical

enter, 981225 Nebraska Medical Center, Omaha, NE 68198-1225;

-mail: [email protected]

2004 American Association of Oral and Maxillofacial Surgeons

278-2391/04/6209-0205$30.00/0

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rticle to aid in this decision, rather to familiarize theeader with literature reviewing success rates of fixedartial dentures (FPDs) and single-tooth implant res-orations and a repertoire of prosthodontic tech-iques used in the replacement of single missing teethith osseointegrated dental implants.

ixed Partial Denture Success

The FPD has been regarded as the standard of careor some time in the replacement of single and mul-iple missing teeth. However, to obtain optimal func-ional and aesthetic results for full-veneer FPDs, aignificant reduction in the amount of tooth structures necessary occasionally predisposing to endodontic,eriodontal, and structural complications (Fig 4).any studies surveying long-term survival have been

ompiled and analyzed to arrive at a generalized out-ome. Creugers et al’s1 study was inclusive of 26tudies that followed multi-unit fixed replacementsor 15� years. A literature search was performed onhe dental literature from 1970 to 1994, presenting
linical data of conventional bridges. Forty-two pub-

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SALINAS, BLOCK, AND SADAN 3

ications were found that contained durability data ofonventional fixed bridges. These publications dealtith 33 different samples. According to the exclusion

riteria, 26 studies were excluded for the meta-analy-is and the remaining data of 4,118 conventionalridges were analyzed. The definition of failure in thisompilation meant that the bridge was not present oror any reason a remake was required. Meta-analysis isstatistical method that identifies trends in multiple

tudies arriving at a common conclusion. This can bespecially useful when predicting outcomes of proce-ures that have only been performed for a shorteriod of time. With studies that are few and followp-periods limited, performing a statistical analysisnd arriving at clinically relevant conclusions may beetter achieved by combining them for meta-analysis.he calculated overall survival rate in this study was

IGURE 1. Caries extending subgingivally below the level of alveolarone may frequently necessitate removal based on lack of adequate

ooth structure for creation of ferrule effect.

alinas, Block, and Sadan. FPD Versus Single Tooth Implantestoration. J Oral Maxillofac Surg 2004.

IGURE 2. Traumatic fracture of both central incisors may necessitateemoval of teeth in instances where root length is insufficient forrthodontic extrusion.

alinas, Block, and Sadan. FPD Versus Single Tooth Implant
estoration. J Oral Maxillofac Surg 2004. R
0% after 10 years and 74.0 � 2.1% after 15 years.riticism of this study would indicate the lack ofefining what survival meant. Any misclassification ofailure could lead to an overestimate or underestimatef FPD survival.Scurria’s Medline search2 incorporated all studies

ublished in English from 1966 to 1996 and evaluatedstudies by Kaplan-Meier modeling to calculate sur-

ival probability and combined the proportionshrough meta-analysis. Less than 15% of FPDs wereemoved or in need of replacement at 10 years. At 15ears, the statistics changed dramatically in thatearly one third were removed or in need of replace-ent. This equates to FPD removal as failure, 92%

uccess at 10 years and 75% success at 15 years. Thistudy almost duplicates the Creugers et al study1 4

IGURE 3. Residual periapical pathology that is unresolved despitefforts at nonsurgical and surgical endodontics.


IGURE 4. Full veneer preparation for FPD. Required reduction mayredispose abutment teeth to endodontic complications and subse-uent failure by recurrent caries.

estoration. J Oral Maxillofac Surg 2004.

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4 FPD VERSUS SINGLE TOOTH IMPLANT RESTORATION

ears previous, although different exclusion criteriaesulted in different studies surveyed. When failureas defined as FPD removal, 92% and 75% of the FPDsere estimated to survive at 10 and 15 years, respec-

ively.When a broader definition of failure was used,

amely, combining FPDs removed with those that tech-ically failed and needed replacement, 87% and 69%ere estimated to survive at 10 and 15 years, respec-

ively. Walton3 looked at 515 metal ceramic FPDs longi-udinally for 15 years and reported similar survival rates.actors that predisposed complications included nonvi-al anterior abutments and pier abutments.

It is generally accepted that FPD survival is approx-mately 87% at 10 years, dropping to 69% at 15 years.

General indications for an FPD would be consider-tions for replacement of a single or 2 missing teethy support of abutment teeth with equal or greateroot surface area (Ante’s law4). Fixed partial denturesre applicable to most situations where abutmentrown-to-root ratio is less than 1:1.5

General contraindications to the use of FPD woulde where more than 1:1 crown-to-root ratio of abut-ent exists, excessive mobility of the abutment(s),

nd cantilevered designs on incisor teeth. Based onhe literature review, it is noted that endodonticallyreated anterior teeth are predisposed to long-termailure as FPD abutments, as are pier abutments. Ad-itionally, prospective abutment teeth that were sub-

ect to luxation or avulsion injuries are at significantisk for resorption.6-8 Likewise, teeth that are pulpapped are at high risk for requiring endodontic treat-ent and make poor choices for abutment teeth be-

ause endodontic treatment would remove the toothtructure necessary for long-term stability of an FPD.

ingle-Tooth Implant Success

Studies surveying success of single-tooth implant-upported restorations are not comparably abundantor survey for comparable time as those for FPDs.lthough, many of the outcomes are statistical sur-ival estimates, such as Kaplan-Meier survival tables,mplant restorations in partially dentate patients are aredictable means of tooth replacement. Lindh et al9

earched the English literature between 1986 and996 and retrieved 66 studies of single and multipleooth implant-supported restorations. Inclusion crite-ia applied were threaded cylindrical metallic in-raosseous implants and minimum follow-up periodor 1 year of loading. Implant failure was defined andumulative survival rate calculated. Nine studies con-aining 570 implant-supported single teeth fit the cri-eria for meta-analysis. The survival rate for singlerowns was in the high ninetieth percentile, with the

10
xception of 1 study by Jemt et al, where the sur- c
ival rate was 91.3% after 3 years. It could be arguedhat the failure rate in this study can be correlated tondeveloped prosthetic components for single-tootheplacement. Another study, by Buser et al,11 re-iewed a mix of single-tooth and free-standing FPDrostheses supported by ITI implants (StraumannSA, Waltham, MA) installed as a 1-stage protocol.his showed similar results in all of the other Bråne-ark studies. Of the 9 studies, 5 were prospective andwere retrospective. There was no significant differ-

nce in cumulative survival between the groups (98.0s 97.0). These studies reflect most failures occurringuring the first year of service.Eckert and Wollan12 reviewed 1,170 implants in the

artially dentate arch for which the cumulative sur-ival rates were based on 4 divisions of the oral cavitynto the anterior/posterior mandible and maxilla. Theumulative 10-year survival in all but posterior man-ible was in the mid to high 90s percent. Cement-etained restorations were included in the study andad cement failures at 5 years of 22.5%. What is notedo be of significance with this report is identifying aeference date of June 1, 1991. Prosthetic compo-ents were improved after this time, and this studyeflects a statistically significant improvement of im-lant survival for combined maxillary and mandibularosterior implants. The relative risk for implantslaced and restored before June 1991 indicates thatajor complications occur 2.096 times as frequentlyith older prosthetic components than with theewer components (P � .0110). Reduction in screw

oosening decreased from more than 46% to 3.2%fter abutment screw redesign.

Another comprehensive literature review by Good-cre et al13 and colleagues compiled all available stud-es from 1981 to 1997 published in English. It re-orted types of complications related to types ofrosthesis, arch, time, implant length, and bone qual-

ty. In comparison to other prosthetic designs, im-lant single crowns had the lowest failure rate at.7%. The types of studies related to follow-up of

mplants supporting crowns that were placed andost, and time of loss were limited to 4 combinedtudies; 3.6% were lost postprosthetically. (Implantoss in the second year was significantly lower thanhe first year, as was the third year.) Although therticle cited single-tooth restorations as having com-lications of prosthetic/abutment screw looseningrevalent in the premolar and molar area, many of thearly studies used abutment screws made of titanium;he change to gold alloy screws and the use ofounter torque devices made the incidence of thisroblem much less.Naert et al’s study14 was aimed at surveying the

uccess of the implant, prosthesis, and biologic out-
ome (bone levels). The study was 12 years long and

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aried in its length of time of assessment. The major-ty of failures occurred at stage II or within 6 months.

The cumulative success for the implants was 93%.he prostheses survival was 96.5% over the 11-yeareriod. The first 6 months after abutment connectionesulted in a 0.71 mm bone loss to an annual of.036 mm over the remaining 10-year period.Treatment of partially dentate patients with osseointe-

rated implants has comparably limited data, but thesereliminary estimates show that success rates for single-ooth implant-supported restorations approach the high0th percent at 8 to 10 years. This assumes the implant

ntegrates and what is quoted is inclusive of prostheticomplications of abutment/coping screw loosening andorcelain fracture.15 In the case of osseointegration fail-re, limited to no detrimental effect would be encoun-ered with abutment teeth as opposed to failure of aPD. Comparing these scenarios may encompass eitheretreatment with an implant restoration or with a FPD.mplant restorations, therefore, offer a distinct predict-ble advantage over FPDs for replacement of singleissing teeth.General indications for the use of an implant-sup-

orted restoration would predicate first on the con-ition of the abutment teeth. Abutment teeth withoutestoration or the need for restoration, abutmenteeth with large pulp chambers, are better left free ofoverage because long-term success is at risk as citedreviously. Nonvital abutment teeth, abutment teethith a history of avulsion or luxation, and abutment

eeth that are prospective pier abutments for eitherxed or removable partial dentures are all high riskor FPD failure long-term and point to the alternativef implant restorations for better outcome. The con-ition of the implant site may also give indicationhether an implant restoration is the correct choice.he prospective implant site should possess a fullomplement of bone and soft tissue in the implantite or the potential to create it, minimum restorativend surgical mesiodistal dimension of 6 mm, mini-um vertical surgical dimension of 10 to 12 mm of

one, and available restorative dimension to providerosthetic material for aesthetics and occlusal func-ion. Secondary indications for implant restorationsre patients who desire a restoration similar to naturalooth aesthetics that facilitate regular hygiene proce-ures.Contraindications for the use of an implant restora-

ion are in developing patients (particularly in the max-lla, where vertical growth continues after permanenteeth are fully erupted), uncontrolled periodontal dis-ase, aesthetic areas with thin, highly scalloped gingiva,djacent periapical pathology, and nonmotivated pa-ients. Relative contraindications where adjacent rootaring precludes placement (correction needed with
rthodontics), smokers (increased failure rate especially d
n type IV bone),16,17 connective tissue diseases,18 andiabetes and autoimmune diseases.19,20

reatment Planning

Primary selection of appropriate single missingooth cases begins with a thorough clinical examina-ion to include adequate quantity and quality of hardnd soft tissue. This requires an adequate band oferatinized tissue where peri-implant tissues are to beocated. Specifically, 3 to 5 mm of keratinized tissueo the facial and lingual aids in hygiene proceduresnd is easily maintained (Fig 5). Also, mesiodistalrosthetic (proximal contacts) spacing of at least 6m for most missing teeth is appropriate for installa-

ion of standard implant diameter unless mandibularncisors or maxillary lateral incisors are being re-laced. The surgical distance can be calculated fromeriapical radiographs and may be tailored more ap-ropriately to modern tapered implant designs (Fig). Vertical restorative space should also be assessedor proper restorative height. This is best completedith a diagnostic wax-up, which will help aid in theesign of the final prosthesis. In general, screw-re-ained restorations will be of aid in those spaces thatre constricted in vertical height (less than 6 mm).hen these dimensions are not available, it occasion-

lly becomes necessary to treat the adjacent or oppos-ng dentition with orthodontics or restorative den-istry to optimize the treatment outcome. Periodontaliotyping is also of prime importance because manyf those cases with missing teeth in the aesthetic zoneecome challenging when the teeth take on a taperedorm and the corresponding gingiva is highly scal-oped (Fig 7). In these cases, there is a significant

IGURE 5. Presurgical assessment begins with the inspection of softissues. Adequate band of keratinized mucosa is essential.


ifference in the attachment height between the in-

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erproximal and facial areas. Therefore, minimal insulto the adjacent periodontium becomes critical whenelecting the vertical placement of the implant plat-orm.

RADIOGRAPHS

A standard radiographic survey starts with periapi-al radiographs to appreciate the periodontal healthf the adjacent dentition. The periodontal biology ofurrounding teeth is a critical factor of success be-ause the interproximal bone is largely maintained byhe neighboring teeth. Root inclination is better ap-

IGURE 6. Presurgical planning of extraction of tooth #7 (nonrestor-ble) and immediate replacement with tapered implant.


reciated from a periapical film to ascertain if the site R

an accommodate installation of an implant. Pan-ramic radiographs are also helpful to determinelacement height over a mandibular canal, nasal floor,r sinus floor (Fig 8). Magnification on or about 25% isypical to interpolate these measurements to actualagnitude. More specific methods of calculating thisagnification mandates the use of radio-opaque ob-

ects known to size incorporated into the film (Fig 9).

IMPLANT SELECTION

Philosophies of treating partially dentate patientsave changed significantly over the last several years.apered implants afford greater stability in relativelyorous bone allowing more 1-stage or immediate-

oading treatment options. These contemporary de-igns also incorporate restorative hardware conduciveo treating these cases aesthetically with immediateestoration or 1-staged procedures. Internal connec-ion type implants also offer an advantage of less

IGURE 7. Thin scalloped gingiva that may create difficulties relatedo tissue migration. Note the significant differences in height betweenapilla and facial gingiva.


FIGURE 8. Panorex indicating positions of inferior alveolar canals.


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tress to the abutment screw and reduced verticalpace requirement for restorative hardware. Two-taged procedures have excellent data, and althoughhey are more difficult to re-establish soft tissue, areetter suited in cases with “difficult-to-control” occlu-ion. Therefore, the choice of using a 1- or 2-stagedpproach with a standard external hexed implantersus tapered-screw design with internal connectionests with the preference of the treating team.

urgical Considerations

Optimal spatial location for an osseointegrated im-lant is based on several biologic principles. First,eri-implant biology is similar to natural teeth21 inhat standard biologic height is commonly found.22 Ineneral, vertical placement of the implant platformhould not exceed 3.5 to 4 mm apical to the adjacentingival margins. The horizontal distance that an im-lant assumes from the adjacent tooth should approx-

mate 2 mm to preserve the viability of bone.23 Theseuidelines serve as general suggestions; in some caseshere a thin scalloped periodontal biotype is present,

ecession of soft tissues and resorption of bone be-omes an even greater concern. In these cases, inter-isciplinary consulting with orthodontics and peri-dontal grafting may be deemed appropriate. Surgicaltents made of thermoplastic vacuform material.04-inch thickness) are especially useful for aidinglacement of the implant (Fig 10). These stents areost-effective, easily made, and require minimal to nodjustment for proper fitting. They should convey 2ain pieces of information: the occlusal/incisal plane

nd cervical margin. When bone grafting is concom-tantly performed with implant placement, thesetents also serve well to provide a tooth-supportedooth replacement without mobilizing bone graft ma-erials. Soft tissue grafts may be used in the interim

IGURE 9. Panorex with stainless steel shots indicating that theagnification factor is present.


hase between placement and uncovering. These can R

e taken from the posterior hard palate from subcu-aneous tissue.

rosthetic Considerations

Implant restorations for single teeth in the aes-hetic zone can be a challenge to maintain soft-issue position and contour. It is generally acceptedhat bone loss occurs around implants in the first 18onths under Albreksston’s criteria of success.24

s a result of this bone loss, soft tissues follow thehange in topography and may expose either theestorative components and/or the implant body.nticipating this loss in the aesthetic zone mayictate specifically locating the implant strategically

n the confines of peri-implant biology as well asamouflaging restorative components by using ce-amic materials.

The 2 major designs of single-tooth implant resto-ations are cemented or screw-retained. A combina-ion of both designs, screwmented, may be used inases where angle correction is needed and specificetention to the abutment is achieved by customcrew retention in an orientation different than themplant long axis (Fig 11).25 This alternative design issed in gold or porcelain fused to metal restorationsnly. Cemented-designed restorations are often indi-ated where angle correction is needed from themplant axis relative to the tooth long axis. This isrequently seen in the maxillary anterior area, whererientation of greatest bone is disparate from the longxis of the teeth. Cemented-designed prostheses fornterior teeth mandate placement of the long axishrough the palatal aspect of the incisal edge. Forosterior restorations, the long axis should be aimedhrough the center of the occlusal table. A cementedesign incorporates the use of an abutment with a

IGURE 10. Surgical stent made from a .04 inch vacuform materials self-retained during the surgical procedure.


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otal occlusal convergence of 6°, similar to standardooth preparation. This abutment may be made of 3ain materials: titanium, cast gold alloy, or high-

trength ceramics (alumina, zirconium) (Fig 12). Al-hough titanium has a predictable biologic attach-ent,26 its use in the aesthetic zone may beroblematic as a grey sheen can be appreciated

IGURE 11. A, Cast gold abutments with tube and screw attachmemented and screwed in place for retention.

alinas, Block, and Sadan. FPD Versus Single Tooth Implant Res

hrough thin gingiva. In these cases, the use of high-trength ceramics affords better opportunity for ac-eptable aesthetic outcomes and location of the re-torative interface.

Screw-retained designs start with meticulous place-ent of the implant axis through a specified area of

he restoration. In anterior teeth, this mandates place-

the screwmented design. B, Porcelain fused to metal crowns to be

n. J Oral Maxillofac Surg 2004.

IGURE 12. A,Titanium abutment of the standard stock design. B,orcelain-fused metal abutment camouflaged with gingival porcelain., Zirconium abutment used for cemented restoration.


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ent through the cingulum area for concealment ofhe access channel. Secondly, the use of a prema-hined abutment may be preferable in cases wherehe biologic height exceeds 3 mm. It is the preferencef the author to make screw-retained restorationsingle piece, which allows simplicity of placementnd retrieval, if necessary. Screw-retained restorationffers distinct advantages over cemented restorations

n that cement retrieval is avoided, subgingival emer-ence with porcelain is predictable, and retrievinghe restoration is also very predictable. Posterior res-orations, if planned well, can be exclusively screw-etained, allowing more versatility and retreivability.

ONE STAGE

One-stage placement of the implant may be prefer-ble either some time after tooth extraction or theame day of tooth extraction. With the 1-stage ap-roach, the decision to place a provisional restorationay be based on primary stability of the implant and

he ability to properly control occlusion. Usually, theecision of placing a restoration on a 1-stage implant

s associated with single missing teeth in the aestheticone (Fig 13). Otherwise there is limited reasoning forroviding a provisional restoration unless the opera-or wishes to transitionally load the implant or formoft tissues from the time of implant placement, sim-lifying impression procedures for the definitive res-oration at a later time. If the implant is placed in aonaesthetically critical area, it is merely a matter oflacing a gingival healing abutment and closing tissueround it.

Suggested protocol for making a provisional resto-ation with 1-stage implant placement may be accom-

IGURE 13. A, Implant placed in the patient shown in Figure 6 wiestoration inserted on provisional abutment.


lished in 1 of 3 routes:

1. Fabrication of the provisional by mock place-ment of an implant in a diagnostic cast.

2. Fabrication of the provisional/abutment chair-side after implant placement (Fig 14).

3. Impression of the implant after placement andfabrication in the laboratory with delivery thesame day or a short time thereafter.

TWO STAGE

Usually, 2-stage surgical protocol of implant resto-ation may allow either the use or not of a provisionalestoration. Provisional restorations are indicated ineveral clinical circumstances:

1. Where a cemented restoration will be used inthe aesthetic zone.

2. Where screw-retained restorations will be usedin the aesthetic zone.

3. Where soft-tissue profiles are in need of re-establishment.

4. Where orthodontic anchorage is needed for re-establishment of space.

Suggested protocol for making a provisional resto-ation with 2-stage implant placement may be accom-lished in 1 of 3 routes:

1. Fabrication of the provisional on a modifieddiagnostic cast created from a surgical index ofthe implant at stage I (Fig 15).

2. Fabrication of the provisional from a fixture-level impression of the implant.

3. Fabrication of the provisional chair-side withrestorative components (Fig 16).

ment attached the same day of extraction. B, Immediate provisional


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mpression ProceduresAfter soft tissues have been formed, adequate time

hould transpire before impression procedures areegun. If a cemented restoration will be made, it is

IGURE 14. A, Insertion of a screw-type implant into site 8. B, Prepaeramic abutment on the implant platform. D, Suturing of peri-implant


IGURE 15. A, Surgical index of the implant platform created by impeight of contour. B, Modification of the diagnostic cast to receive tbutment/provisional can be completed in the laboratory.

alinas, Block, and Sadan. FPD Versus Single Tooth Implant Restoratio

ery important to know the exact soft tissue margino that the proper level of prosthesis/abutment con-ection is created at the appropriate level. The prac-itioner has the choice at this point to decide if a

of the abutment under copious irrigation. C, Insertion of the preparedaround the cemented provisional created chair-side.


coping. Note that care is taken to avoid extending the acrylic underant analog. The void will be filled in with stone and creation of the

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irect or indirect approach is preferable for fabrica-ion.

The direct impression uses conventional crownnd bridge procedures with gentle cord packing and

IGURE 16. A, Punch uncovering of a previously placed implant. B, Mreated from auto-polymerizing acrylic resin. D, Placement of tempora


IGURE 17. A, Patient depicted in Figure 14 where soft tissues havegular crown and bridge technique. B, Final result of the alumina co


lastomeric impression material (Fig 17). This tech-ique is preferable with white or high-strength ce-amic abutments because the finish line for thesebutments is similar to that of porcelain veneers and

tion to the titanium abutment. C, Centric stop and denture tooth facingart formation of soft tissues to the ideal contour.


d to allow direct impression of the abutment with retraction cord andration cemented onto the alumina abutment.

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ay be placed at or slightly below the free gingivalargin. There are distinct advantages to the use of

his technique because no additional componentsther than the abutment itself are needed to completehe restoration. Therefore, only 1 abutment is needed,nlike the indirect procedure, which uses both pro-isional and definitive abutments. A disadvantage tohe technique may be leaving impression materialround the abutment without directly visualizing it.eticulous inspection after the impression is sug-

ested to minimize soft tissue reaction.The indirect impression procedure (also known asfixture level transfer) incorporates the use of com-onents to transfer the position of the implant plat-

orm (Fig 18). This may use the provisional restora-ion/abutment or a customized impression post.27 Aay of customizing the impression post is to use aowable composite resin into the sulcus shortly afteremoval of the provisional restoration and abutment.f the restoration is screw-retained, an extended-ength screw from the impression post can be usednd a pick-up impression made to transfer both im-lant position and soft tissue profile (Fig 19). The goal

IGURE 18. A, Soft tissues formed by the provisional to ideal contouodification by flowable composite. C, Soft tissue cast created from

estoration made on the abutment. D, The final all-ceramic restoration


s to make a soft tissue master cast that duplicates theoft tissue profiles and implant position in the mouth.he advantage to this technique is to clearly visualize

he implant platform and soft tissue architecture, al-owing planning of where to establish the prosthesis/butment margin. Also, the prosthesis can be fabri-ated directly on the abutment ensuring an intimatet between the abutment and prosthesis. If a screw-etained restoration will be fabricated, subtle contourhanges can be incorporated to reshape the surround-ng gingiva.

elivery ProceduresThe first procedures to take place at the delivery

ppointment involve removal of the provisionalnd/or abutment with careful inspection to eradicateny residual debris from the gingival area. Second, if aemented design is used, a placement jig can beeneficial to facilitate placement of the abutment inhe correct position (Fig 20). After the abutment haseen placed, it should be secured with an abutmentcrew by hand-tightening only at this point. A radio-

ovisional and abutment are removed and impression post inserted fore level impression. Components are selected in the laboratory andented to the alumina abutment.

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raph should be made with the incident beam per-endicular to the long axis of the implant. After com-lete seating is affirmed, trial insertion of the crownhould be accomplished in the usual fashion by prox-mal contact adjustment with subsequent occlusalorrection (Fig 21). An additional radiograph can beade to determine complete seating on the abut-

IGURE 20. A, Insertion of 3 abutments using a positioning jig fromosition after securing the abutment screws.


ent. After it is determined that the restoration fitsorrectly and occlusion is functional and aestheticallyleasing, the abutment screw is then tightened to theecommended torque value. This should be per-ormed with a recommended torque wrench cor-ectly calibrated, with a repeat torque 5 minutes afterhe first torque application.28 A screw-retained resto-

IGURE 19. A, An extended-length impression pin is placed throughhe access channel of the screw-retained restoration. B, An open trayick-up impression of the provisional restoration used to create the soft

issue master cast preserving the soft tissue profile. C, Attachment of themplant replica and addition of the soft tissue simulation before pouringhe master cast.


ent teeth. B, Placement of 1 alumina and 2 titanium abutments into

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ation is inserted in the same fashion, with attentionaid to proximal contacts first and complete seatingefore adjustment of occlusal contacts. This is espe-ially true if a significant change will be made to theoft tissue topography and no provisional restorationas used before the final impression. In extreme

ases, it may be necessary to create a releasing inci-ion in the col or lingual gingiva area to allow com-lete seating. After complete seating of the restora-ion has been confirmed, the access channels of eitherhe abutment or restoration should be closed withome material to protect the screw head from subse-uent defacement by rotary instrumentation. The usef compacted cotton, vinyl polysiloxane putty, orutta percha are reasonable choices. The addition of a

IGURE 21. A, Insertion of the titanium abutment with hand tightenindjustment of the proximal contacts and occlusal adjustments. Torquingord for retrieval of cement. D, Postcementation follow-up.


estorative material (amalgam or composite resin) m

hould be considered as well if the restoration isingle-piece screw-retained. Therefore, the depth ofhe access channel after placement of protectant ma-erial over the screw should be enough to retain theestoration (2 to 3 mm). Cementation of the prosthe-is can be performed with a myriad of materials tar-eted at either retrieval or retention. Temporary lut-ng cements can be used in cases where it is desirableo remove the restoration periodically. Lubrication ofhe internal portion of the crown can be accom-lished with petrolatum and the use of either a defin-

tive cement or provisional luting agent. This type ofementation is also indicated for restorations that aref sufficient strength to withstand occlusal forcesithout being bonded (gold, porcelain fused to

abutment screw. B, Confirmation of the seating of the abutment andabutment using calibrated torque wrench. C, Packing of the retraction


g of theof the

etal, high-strength bilaminar ceramics). An alter-

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ative to traditional luting cements may allow these of silicone materials that seal the internal areasf the abutment restoration interface as well. Rela-ively definitive luting or bonding agents can alsoe used where a more stringent retentive capacity

s needed. This is indicated for restorations that areot of sufficient strength to withstand occlusal load-

ng on their own (such as leucite reinforced all-eramic restorations). Meticulous attention to en-ure no residual cement is left behind can beddressed by careful use of retraction cords, scal-ng, and post-cementation radiographs.

If an auxiliary screw is used for the screwmentedesign, it should be inserted before set of the lutingement. In these cases, temporary luting cements areore appropriate to allow some element of retriev-

bility should the need arise (Fig 22).

roubleshooting

Many complications associated with implant-sup-orted single-tooth restorations are related to abut-

IGURE 23. A, Postcementation of # 9. Note the position of ginissues.

IGURE 22. A, Combination cemented crown and set screw for auxith veneers. (Courtesy of Dr Sean McCarthy.)



ent screw loosening and porcelain fracture. Becauseroprioception is largely absent with dental implants,cclusal contacts should be meticulously adjusted byffirming a slightly heavier contact on the adjacententition with (0.001 inch) stainless steel shimstock.ateral excursion and anterior guidance should behared with adjacent anterior teeth to minimize theotential for screw loosening. These are relativelyommon complications related to insufficient torquepplication, excessive lateral loads, and occlusal pre-aturities. This may be especially problematic with

emented restorations, whereby the abutment screwecomes loose but the restoration maintains its ce-ented and intimate relation to the abutment. In

hese cases, it may be prudent to remove the restora-ion from the abutment if cementation was performedn a provisional basis. If not, it may be wise to at-empt at removing the abutment screw by creating anccess channel through the restoration. This may beided by consulting the master cast for orientation ofhe implant long axis. In anterior restorations, the

d papilla. B, Three-year follow-up of a case with migration of soft

tention #6. B, The final aesthetic result of osseointegrated implant #6


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mplant long axis may traverse through the incisaldge and sacrifice of the restoration is occasionallyecessary.Other complications are related to soft tissue/aes-

hetic complications that, in the aesthetic zone, cane problematic to maintain the integrity of papilla andacial gingival margin (Fig 23). Apparently, the pre-ictability of losing soft tissue coverage appears to beignificant even at 1 to 2 years.29 Therefore, the use ofingle-tooth implants in the aesthetic zone where theeriodontal biotype is thin scalloped gingiva shoulde cautiously approached due to the long-term softissue loss typically observed in these areas.

Since the introduction of osseointegration, the levelf predictability was extended to incorporate treatingartially dentate patients. The replacement of singleissing teeth by this method becomes a standard of

are based on this high treatment outcome. High-trength ceramics, contemporary dental materials,nd newer implant designs allow a unique approacho these challenging cases in the aesthetic zone.

eferences1. Creugers NH, Kayser AF, van’t Hof MA: A meta-analysis of

durability data on conventional fixed bridges. Community DentOral Epidemiol 22:448, 1994

2. Scurria MS, Bader JD, Shugars DA: A meta analysis of fixedpartial denture survival: Prostheses and abutments. J ProsthetDent 79:459, 1998

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1. Gargiulo AW, Wentz FM, Orban B: Dimensions and relations ofthe dento-gingival junction in humans. J Periodontol 32:261,1961

2. Cochran DL, Hermann JS, Schenk RK, et al: Biologic widtharound titanium implants. A histometric analysis of the im-planto-gingival junction around unloaded and loaded nonsub-merged implants in the canine mandible. J Periodontal 68:186,1997

3. Tarnow DP, Cho SC, Wallace SS: The effect of interimplantdistance on the height of inter-implant bone crest. J Periodon-tol 71:546, 2000

4. Albrektsson T, Zarb GA, Worthington P, et al: The long termefficacy of currently used dental implants: A review and pro-posed criteria of success. Int J Oral Maxillofac Implants 1:11,1986

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6. Abrahamsson I, Berglundh T, Glantz PO, et al: The mucosalattachment at different abutments. An experimental study indogs. J Clin Periodontal 25:721, 1998

7. Hinds KF: Custom impression coping for an exact registrationof the healed tissue in the aesthetic implant restoration. Int JPeriodont Restorative Dent 17:584, 1997

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9. Bengazi F, Wennstrom JL, Lekholm U: Recession of the softtissue margin at oral implants. A 2 year longitudinal prospec-tive study. Clin Oral Implants Res 7:303, 1996

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