Clinieal

First molar replacement with an osseointegrated implantThomas J. Balshi*

The effective use of two osseointegrated Brânemark implants for ¡lie replacement of asingle first molar is described. A Jirst molar lost to endodontic failure was replacedusing two lO-mm titanium ftxtures in the area previously occupied by the mesial anddistal roots of the molar. The use of multiple flxtures in the molar area provided abetter distribution of forces to the alveolar bone. At 1-year recall, the patient exhibitedexeellent oral hygiene and normal function. Adequate bone dimensions are a prerequi-site to this treatment. (Quintessence Int 1990:21:61-65.)

Intro tluctioD

The efficiency of the Brânemark method of osseoin-tegration for restoration of the completely edentulousjaw is well documented.'"' Restoration ofthe partiallyedentulous patient using osseointegration is also il-lustrated in the dental literature.*'' Replacement of thesingle tooth using a single osseointegrated implant isalso reported*-̂ as a viable treatment method; however,most examples of single-tooth replacement are illus-trated by anterior teeth.

This article describes the effective use of two os-seointegrated Brânemark implants for the replace-metJt of a single molar. Adequate bone dimensions area prerequisite to this treatment.

Fig la Preoperative clinical view ol a long-standing acryl-ic resin provisional fixed partial denture in the mandibularieft posterior area to replace the first molar.

Case report

Patient history

The patient was a 39-year old woman in excellent gen-eral health and with no known allergies or sensitivitiesto medications. However, she had difficulty with pre-vious restorative and endodontie Iherapy, particularly

in the mandibular left posterior area. Endodontic fail-ure led to the loss ofthe first molar 2 years before theinitial examination. Efforts to replace the missingtooth were incomplete when the patient presented forprosthodontic evaluation (Fig la).

The patient's primary concern focused on the dif-ficulty of, and her frustration in, performing idealplaque control procedures in the area of the provi-sional fixed partial denture. She expressed a desire torestore the area with individual teeth.

Prosthodontics Intermedica, Institute for Facial Esthelics, 467PenDsylvania Avenue, Fort Washington, Pennsylvaiua 19034.

Clinical and radiographie examination

Initial elinical evaluation examination revealed a se-verely worn acrylic resin provisional fixed partial den-ture, replacing the first molar, extending from the first

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Fig lb Preoperative radiographsindicate adequate mature boneavailable for fixture placement inthe first molar area.

Fig 2 (top) Facial view ol the compieted individual resto-rations, (bottom) Holes in the central fossa ot tooth 19 pro-vide access to the goid prosthetic screws.

premolar to the second molar. Periodontal health inthe area appeared clinically excellent. Radiographicexamination (Fig lb) indicated completed endodontictreatment for the second premolar and second molar.The first premolar had been prepared for a completecrown, without indication for endodontic treatment.

Trt'alment

A precision surgical guidestent,' fabricated after re-preparation ofthe abutment teeth and restoration ofthe second premolar with a cast gold post and core,enabled the surgical placement of two 10-mm titaniumBrânemark fixtures (implants). These fixtures wereplaced in the area previously occupied by the mesialand distal roots of the mandibular left first molar.

During the initial healing period, the patient con-tinued to wear a newly fabricated four-tooth provi-sional ñxcd partial denture, which had adequate reliefin the pontic area to prevent any pressure on the sur-gical site.

Following the 3-month healing period, the secondstage of the surgical procedure was performed. Three-millimeter titanium abutment connectors were secure-ly fastened to both fixtures.

To obtain an accurate relationship between the ti-tanium fixtures, the impression copings were joinedtogether using autocuring acrylic resin. Conventionalretraction of the gingival suleus tissues was used, andan elastic impression was made using vinyl polysilox-ane. After the master impression was made, the acrylicresin provisional restoration was recemented to theabutment teeth. The area heneath the pontic was mod-ified with additional acrylic resin to contact the abut-ment connectors lightly; however, no cetnent was usedover the abutment cyhnders.'"

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Clinical Ce:

Fig 3 Conventional porcelain-tused-to-gold crowns arecemented individually to the abutment teetti. Titanium abut-ments are positioned in the mesiai and distai root areas.

Fig 4 Ttie tinal single-tooth, tissue-integrated prosthesisreplacing the mandibular left first molar restores the integ-rity of the areti.

Fig 5 The buccolingual dimensions ot the single-tooth, tis-sue-integrated prosthesis provides normal contours and es-thetics.

Fig 6 Postoperative pantomographcomplete dentition.

ustrates an intact

The laboratory procedures included the fabricationof individual crowns, made of porcelain fused to high-gold-content alloy, for the first and second premolarsand the second molar. Two gold prosthetic cyhndersseeurely fastened to the brass abutment analogs wereincorporated into the substructure for tbe tissue-in-tegrated molar replacement. Porcelain was apphed tothe tissue-integrated prosthesis framework for ibc firstmolar. The dropping of porcelain powder into thescrew access openings from the oeclusal surfaee wasavoided (Fig 2).

Dehvery of the final prosthodontic restoration in-eluded confirmation that proximal contact, allowedIhe patient to perform traditional oral hygiene pro-

cedures using dental floss between the restored teethand the tissue-integrated prosthesis. The crowns werecemented to the teeth with zinc oxyphosphate cernent(Fig 3). Delivery of the poreelatn-fu sed-to-gold, tissue-integrated molar replacement (Fig 4} followed thor-ough removal of all excess cement. The buccal andlingual contours of the tissue-integrated prosthesis, aswell as the individual crowns, restored the areh ahgn-ment, the occlusal plane, function, and esthetics (Fig5),

The postoperative pantomograph (Fig 6) illustratesthe eompleted restoration of the mandibular left pos-terior. The prcoperative penapical radiograph (Fig 7a)clearly shows the inferior alveolar canal and proposed

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Fig 7a Preoperative periapicai radiograph shows the in-terior alveolar canal and proposed itnpiant receptor site.

Fig 7b Postoperative periapical radiograph confirtns theaccurate tit of the individual conventional crowns and thesingle-moiar, tissue-in te g rated prosthesis.

Fig 7c Radiograph 1 year postoperatively.

implant receptor site. The postoperative periapical ra-diograph (Fig 7b) continus the accurate fit of the in-dividual convetitional porcelain-fused-to-gold crown.sand the sing le-mo lar, ti s sue-in teg rated prosthesis atthe time of delivery. Radiographie exatnination of thetreated area 1 year later indicated a stable periodontalcondition for the restored teeth, with httle or no boneloss associated with the osseointegrated fixtures (Fig7c).

Oral hygiene

After the restoration was completed, the patient's levelof frustration regarding oral hygiene techniques wasalleviated. Plaque-control instruction included the useof a custom-angled end-tufted toothbrush. Superfloss

(Educational Health Products, Inc) between the twotitanium abutments, an irterproximal brush betweenthe implant-supported molar and the adjacent naturaldentition, and Peridex oral rinse (Procter & Gamble)as a plaque-suppressing agent.

One year followtng the delivery of the final pros-thesis, the patient continued to exhibit superb oralhygiene and indicated that she enjoyed normal func-tion without conscious recollection of her partial ed-entulism.

Discussion

Although conventional fixed partial prosthodonticswould traditionally have been prescribed for a patientpresenting with this clinical condition, the Brânemarkmethod of osseointegration was used because of thepatient's strong desire to avotd having a splinted pros-thesis and her desire to have this quadrant restoredwith individual restorations.

Summary

A method of replacing a missing single molar usingtwo osseointegrated fixtures has been described. Thisclinical example illustrates a conservative approach toprosthodontic treatment that fulfilled the patient's de-sire for individual-tooth restoration and simultane-ously restored integrity of the arch, function, and es-thetics.

The use of osseointegrated fixtures should be con-sidered a conservative approach to the replacement oflost rnolars. Availability of single-tooth replacementsystems compatible with Brânemark osseointegrated

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Clinical Co

fixtures pemiits the use of a single fixture to accom-plish Ihe same clinical rcsitlts; however, it is my opin-ioti that multiple fixtures in the molar area providebelter distribution of forces to ihe alveolar bone.

In the mandibular arch, the inferior alveolar canalmay prevent ihe placetnent of long fixtures. However,it appears that the stability provided by two lO-mnilong osseointegrated fixtures yields a bone-anchoredrestoration with a crown/root ratio similar to that ofthe natural dentition. It is my opinion liiat use of twofixtures offers greater prosthesis stability for molarreplacement than does the use of a single fixture, nolbecause the strength of the single-fixture osseointe-grated interface cannot withstand functional forces,but rather because the distribution of stress lo thecontact areas of the machined screw joint componentsimproves when multiple abutments arc used.

Additional long-term studies are needed to ascertainthe effectiveness of this treatment method.

AcknowledgmentsThe author would like to acknowledge the labordtory skills of llielaboratory technicians of the Fort Washington Dental Lab, in pur-iicular Mr Ken Orth and Mr .̂ ilfonso Greco, and Ms Liz Kirk forprepiration of this manuscript.

References

I Hrùncmark P-1, Haiissoti BO, Adcll R. et ¡i\: OsseointegratedImplants in the Trealmeni o) the liitentutoti.y Jaw. Stocktiolm,Mmquist und Wiksell, 1977,

2. Adell R, Lekholm U, Rockier B, et al: A 15-year stndy of os-se oin teg rated implants in the treatment of the edentulous jaw.ItU J Oral Surg t9Kl;IO:3R7^l6,

Í. Haroldson T, Carlsson GE; Bite forte and oral function in pa-tients with osseointegrated oral implants, Scand J DenI ResI977;85:2O0,

4. Brânemark P-I, Zarb GA, Albrektsson 1: Tissue-lntef;ratedProstheses: O.'^xeointegration lit Clinical Denti.\try. Chicago,Quintessence Pubi Co, 1985,

5, Balsbi TJ: Converting patients with periodontaily hopeless teethto osseointegration prostheses. Int J Period ont Res Dem

6. Ericsson 1, Lekholm Ü, Brânemark V-l, et al: A clinical eval-uation of fised-bridge restoration supported by the combinationof teeth and osseointegrated titanium implants, J Chii Peri-odontol 1986:13:307-312,

7. Sullivan DY: Prosthetic considerations for the utilisation ofos-seointegrated fixtures in the partially edentulous arch, Inl J OralMaxillofae Implatus 1986:1:39^5,

8, Jemt T: Modified single and shorl-span restorations supportedby osseointegration fixtures in the partially edentulous jaw, JProslhel Dem 1986:55:243-247.

9, Öhrneil L-0, Hirsch JM, Ericsson I, et al: Single-tooth reha-bilitation using osseointegration. A modified surgical and pfos-thodontit approach, Qiiimessenee hit 1988:19:871-876,

10. BLilshi TJ: Osseointegration for the periodontaily compromisedpatient, //(/ J Prosthodoni I988;1:51-SS, D

Quintessence Symposium in Esthetic DentistryMarch 30-31, 1990, Madrid, Spain

ESTHETICS IN THE 90sSpeakers

Ronald E. Goldstein, DDS, USARichard J. Simonsen, DDS, USA

Program Chair and Coordinator-Jaime A. Gil, DDS, Albia Clínica Dental

Edificio Albia 1-13°, S. Vicente 848001 Bilbao, Spain

Quintessence IntVolume 21, Number 1/1990

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