112 THE JOURNAL OF PROSTHETIC DENTISTRY VOLUME 87 NUMBER 1

The choice between cement and screw retentionaffects the esthetics and occlusion of implant restora-tions. The need for prosthetic retrievability in thedevelopment of early implant protocols dictated therequirement for screw retention. However, thedemonstrated high survival rate of dental implants hasmade this requirement less significant. Cement reten-tion for implant restorations is an acceptablealternative to screw retention.1 The advantages ofcement-retained restorations include enhanced abilityto develop esthetics and occlusion because of theabsence of screw access holes, enhanced ability toachieve passive fit for frameworks, easier access torestoration of posterior teeth, and reduced complexityof clinical and laboratory procedures.1-3

When prosthetic retrievability is desired, the con-cept of progressive cementation1 may be applied. Thisallows the retrievability of cement-retained implantrestorations to be controlled with the choice of lutingagent. One can start with weaker provisional cementsand progressively use stronger cements until thedesired level of retention is achieved. Among provi-sional cements tested with implants in one study,4Temp Bond (Kerr, Orange, Calif.) and Provilink(Ivoclar, Amherst, N.Y.) exhibited the lowest meantensile strengths, whereas the bond strength of Neo-Temp (Teledyne Water Pik, Fort Collins, Colo.) was 3times greater than that of Temp Bond.

Situations exist, however, in which the use ofcement-retained restorations may be undesirable. Inareas of limited restorative space, the axial walls ofshort abutments may not provide adequate retentionand resistance form. Retention from the clampingforce provided by a screw would be more effective insuch situations. If the final restorative margin will begreater than 3 mm subgingivally, removal of excesscement may be difficult. This situation is particularlycommon in the anterior region when implants areplaced immediately after tooth extraction. In the ante-rior region, proximal soft tissue height is markedly

greater than facial or lingual soft tissue. If implants arepositioned 3 to 4 mm apical to the cemento-enameljunction or facial gingival margin of adjacent teeth forproper emergence profile,5 the proximal restorativemargin may be too deep subgingivally. This is becauseimplants and abutments have a single-level circularmargin, whereas soft tissue is higher interproximally(Fig. 1). The use of a screw-retained restoration wouldbe indicated in this situation. An alternative would beto fabricate a custom abutment with restorative mar-gins that follow the outline of the gingival contours.This option could also correct implant angulationproblems (Fig. 2).

Several disadvantages of cement-retained restora-tions have been reported.6,7 These include additionaltime required for cementation and removal of excesscement from the sulcus, limited ability to changesuperstructure designs, and reduced ability to modify

Techniques to minimize excess luting agent in cement-retained implant restorations

Herman B. Dumbrigue, DDM,a Azhaar A. Abanomi, BDS,b and Linda L. Cheng, DDSc

Baylor College of Dentistry, Texas A & M University System Health Science Center, Dallas, Texas

aAssistant Professor and Assistant Program Director, AdvancedEducation in General Dentistry.

bResident, Advanced Education in General Dentistry.cResident, Advanced Education in General Dentistry.J Prosthet Dent 2002;87:112-14.

Fig. 1. Gingival margin follows contour of cemento-enameljunction, resulting in more coronal position for interproximalsoft tissue. Implants have restorative margins at single level.

DUMBRIGUE, ABANOMI, AND CHENG THE JOURNAL OF PROSTHETIC DENTISTRY

JANUARY 2002 113

treatment if peri-implant inflammation or verticalbone loss develops.6 Excess cement may be difficult tovisualize and remove from soft tissue depths greaterthan 3 mm. Incomplete removal of cement may resultin peri-implant inflammation, soft tissue swelling,soreness, and bleeding or exudation on probing.7Removal of excess cement with plastic and metalscalers may result in scratches and gouges on theimplant surfaces.8

This article presents techniques to minimize theamount of excess cement used to lute implant restora-tions with the use of ITI solid abutments (StraumannUSA, Cambridge, Mass.).

TECHNIQUES

The following techniques are designed to minimizeexcess cement by reducing the amount of luting agentplaced in the restoration before cementation. Forimplant restorations used in conjunction with ITI solidabutments, place luting agent only on the occlusal halfof the intaglio of the restoration. This amount willprovide sufficient flow to the axial walls cervically andreduce the amount of excess cement along the restora-tive margin. The disadvantage of this technique is thatincomplete sealing of the restorative margin with theluting agent may result (Fig. 3). The resultant micro-gap between the implant fixture and restoration mayharbor subgingival microorganisms with the potentialto cause soft tissue problems.9

Another technique makes use of a practice abutmentor an abutment analog. Fill the intaglio of the implantrestoration with luting agent, and seat it extraorally onthe practice abutment or implant analog. Wipe excesscement with a gloved finger or cotton tip applicator;immediately remove the crown from the analog, andcement it intraorally. Removal of the restoration from

the analog should be in line with the long axis of theanalog to avoid the elimination of too much cementfrom the axial walls of the restoration. The advantage ofthis technique is that a more complete flow of cementto the axial walls and restorative margins of the implantrestoration is achieved. However, a practice abutment orabutment analog needs to be used with a luting agentthat has a longer working time (for example, IRM; LDCaulk Division, Dentsply Intl, Milford, Del.).

Excess cement encountered intraorally with eithertechnique should be removed with a plastic scaler tominimize the depth of scratches and prevent gougingof implant surfaces.8

We acknowledge Dr Charles W. Wakefield for his helpful com-ments and review of the manuscript.

REFERENCES

1. Hebel KS, Gajjar RC. Cement-retained versus screw-retained implantrestorations: achieving optimal occlusion and esthetics in implant den-tistry. J Prosthet Dent 1997;77:28-35.

2. Jones JD, Kaiser DA. A new gingival retraction impression system for aone-stage root-form implant. J Prosthet Dent 1998;80:371-3.

3. Misch CE. Contemporary implant dentistry. 2nd ed. St. Louis (MO):Mosby-Year Book Inc; 1999. p. 549-73.

4. Ramp MH, Dixon DL, Ramp LC, Breeding LC, Barber LL. Tensile bondstrengths of provisional luting agents used with an implant system. JProsthet Dent 1999;81:510-4.

5. Parel SM, Sullivan DY. Esthetics and osseointegration. Dallas (TX): OSIPublishers; 1989. p. 19-23.

6. Breeding LC, Dixon DL, Bogacki MT, Tietge JD. Use of luting agents withan implant system: Part I. J Prosthet Dent 1992;68:737-41.

7. Pauletto N, Lahiffe BJ, Walton JN. Complications associated with excesscement around crowns on osseointegrated implants: a clinical report. IntJ Oral Maxillofac Implants 1999;14:865-8.

8. Agar JR, Cameron SM, Hughbanks JC, Parker MH. Cement removal fromrestorations luted to titanium abutments with simulated subgingival mar-gins. J Prosthet Dent 1997;78:43-7.

9. Quirynen M, Bollen CM, Eyssen H, van Steenberghe D. Microbial pen-etration along the implant components of the Branemark system. An invitro study. Clin Oral Implants Res 1994;5:239-44.

Fig. 3. Absence of excess cement may result in incompletesealing of restorative margins.

Fig. 2. Custom abutments allow restorative margins to fol-low soft tissue contour.

THE JOURNAL OF PROSTHETIC DENTISTRY DUMBRIGUE, ABANOMI, AND CHENG

114 VOLUME 87 NUMBER 1

Reprint requests to:DR HERMAN B. DUMBRIGUE

BAYLOR COLLEGE OF DENTISTRY

TEXAS A & M UNIVERSITY SYSTEM HEALTH SCIENCE CENTER

3302 GASTON AVE, ROOM 601DALLAS, TX 75246FAX: (214)828-8952E-MAIL: hdumbrigue@tambcd.edu

Copyright © 2002 by The Editorial Council of The Journal of ProstheticDentistry.

0022-3913/2002/$35.00 + 0. 10/4/119418

doi:10.1067/mpr.2002.119418

The bonding of composite resin to moist enamel. Walls AW, Lee J, McCabe JF. Br Dent J 2001;191:148-50.

Purpose. The purpose of this study was to determine the effect of a water-contaminated etchedenamel surface on the bond strength of 4 dentin bonding agents.Material and methods. Sixty recently extracted human premolar and molar teeth were used asthe enamel source for this study. Specimens were cleaned, embedded in polyester resin blocks, andground to provide a minimum of 5 mm of fresh enamel surface for bonding. The specimens werestored in distilled water at 4°C before use. Fifteen bond strength measurements were made ofbonds prepared to both moist (tap water applied with a small sponge) and dry etched enamel sur-faces for the following test groups: group 1, Scotchbond 1 with Z-100 composite (3M); group 2,Prime Bond 2.1 with Spectrum TPH (Dentsply Int); and group 3, OptiBond Solo with Prodigy(Kerr). A “classic” unfilled dimethacrylate resin (Margin Bond) with Brilliant (Coltene) was usedas the control. Data were analyzed with Student t tests and 1-way analysis of variance (ANOVA).When ANOVA was significant, the Tukey multiple comparison was used.Results. For the materials in groups 1 and 2, bond strength was not affected by the presence ofwater on the etched enamel surface. A mean bond strength of 25 MPa was achieved for bothmaterials under all test conditions. The material in group 3 showed a 30% increase in bondstrength when formed under water (21.1 MPa compared with 15.4 MPa). The bond strength ofthe control group decreased markedly with water contamination (9.1 MPa compared with 26.8MPa).Conclusion. Within the limitations of this study, the results suggest that etched enamel should berehydrated routinely before bonding composite to its surface with a water-displacing dentin bond-ing system. When a “classic” unfilled resin system is used, the enamel surface should be clean anddry to avoid early and catastrophic bonding failure. 18 References.—RP Renner

Noteworthy Abstractsof theCurrent Literature