Implantes Dentales

Cement Selection for Cement-Retained Crown Technique with Dental Implants
James L. Sheets, DDS,1 Charles Wilcox, DDS, MS,1 & Terry Wilwerding, DDS, MS2
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Professor, Department of Prosthodontics, Creighton University School of Dentistry, Omaha, NE Professor

Keywords Implant; cement; cement-retained crown. Correspondence James L. Sheets, Department of Prosthodontics, Creighton UniversitySchool of Dentistry, 2500 California Plaza, Omaha, NE 68178. E-mail: jsheets@creighton.edu

Abstract
Purpose: The purpose of this study was to assess and compare the retentive nature of common dental cements that have been adapted for use in the implant abutment cement-retained crown (CRC) technique with those specifically formulated for this purpose. Materials and Methods: Ten regulardiameter implant analogs were embedded in stainless steel disks. Unmodified CRC abutments were attached and torqued to 30 Ncm. Test crowns were waxed and cast with base metal alloy. Castings were fitted, cleaned with aluminum oxide, and steam cleaned prior to application of the cement. The cements used were: (1) Temp Bond, (2) UltraTemp, regular, (3) UltraTemp firm, (4) ImProv with petroleum jelly coatingof crown, (5) ImProv without petroleum jelly, (6) Premier Implant with KY Jelly coating of abutment, (7) Premier Implant without KY jelly, (8) TR-2, (9) Fleck’s, (10) Ketac Cem Aplicap, and (11) Fuji Plus Capsule. After cementation, assemblies were stored for 24 hours. Each sample was subjected to a pull-out test using an Instron universal testing machine at a crosshead speed of 5.0 mm/min. Loadsrequired to remove the crowns were recorded, and mean values for each group determined. A one-way ANOVA and a post hoc least square difference (LSD) test were done for pairwise comparison at a confidence interval of 95%. Results: The mean values (±SD) of loads at failure (n = 10) for various cements were as follows (N): Ultratemp, regular 358.6 (±38.2) (Group A), ImProv without petroleum jelly172.4 (±59.6) (Group B), Fleck’s 171.8 (±62.2) (Group B), Ketac Cem 167.8 (±69.1) (Group B), UltraTemp firm 158.8 (±62.7) (Group BC), Fuji Plus 147.5 (±69.7) (Group BC), Premier without KY jelly 131.6 (±31.8) (Group BC), ImProv using petroleum jelly 130.8 (±42.5) (Group BC), Temp Bond 117.8 (±48.3) (Group C), TR-2 41.2 (±16.6) (Group D), and Premier with KY jelly 31.6 (±24.8) (Group D). Groups withthe same letter were not significantly different. Conclusions: Within the limitations of this in vitro study, it is not suggested that any one cement is better than another at retaining cement-retained crowns (CRCs) to implant abutments or that a threshold value must be accomplished to ensure retention. The ranking of cements presented is meant to be a discretionary guide for the clinician indeciding the amount of desired retention between castings and implant abutments.

Accepted 18 September 2006 doi: 10.1111/j.1532-849X.2007.00262.x

The advantages and disadvantages of restoring dental implants with a cement-retained superstructure are well documented;1-5 however, universal applicability of the technique is restricted by its most prominent disadvantage, which is the loss in easeof retrievability of the cemented superstructure.2,4,6,7 This conundrum naturally focuses attention on the choice of cement. On one hand, selection of a cement that is too retentive could lead to damage due to use of aggressive removal techniques; on the other hand, the selection of a cement that is not retentive enough could be a potential source of embarrassment for
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the patient.5,8-10 Asa result, practitioners who desire retrievability have generally gravitated toward using cements with “soft-access” (sub-maximal) retentive properties.1,2,8,11 The most common advantage of the cement-retained crown (CRC) technique is a comfortable familiarity with the clinical and laboratory techniques of conventional fixed dental prostheses, particularly to practitioners accustomed to managing...