Evaluating the effect of the protector cap for castable implant abutments on reverse tightening values.

Autor: Alfaifi MA; Faculty, Department of Prosthetic Dental Sciences, King Khalid University College of Dentistry, Abha, Saudi Arabia; Fellow in Advanced Digital Prosthodontics and Implant Dentistry, Department of Prosthodontics, Loma Linda University School of Dentistry, Loma Linda, Calif. Electronic address: dr.m-a-f@hotmail.com., Wadhwani C; Private practice, Bellevue, Wash; Affiliate Assistant Professor, Department of Restorative Dentistry, University of Washington School of Dentistry, Seattle, Wash., Schwedhelm ER; Clinical Associate Professor, Department of Restorative Dentistry, School of Dentistry, University of Washington, Seattle, Wash., Kattadiyil MT; Professor, Advanced Specialty Education Program in Prosthodontics, Loma Linda University School of Dentistry, Loma Linda, Calif.
Jazyk: angličtina
Zdroj: The Journal of prosthetic dentistry [J Prosthet Dent] 2024 Mar; Vol. 131 (3), pp. 476.e1-476.e7. Date of Electronic Publication: 2022 Nov 17.
DOI: 10.1016/j.prosdent.2022.09.006
Abstrakt: Statement of Problem: Screw loosening is the most common mechanical complication with implant prostheses. How the alteration of implant-to-abutment connection surfaces that occurs during laboratory procedures affects screw loosening is unclear.
Purpose: The purpose of this in vitro study was to compare the reverse tightening value (RTV) differences between custom castable abutments before casting, after casting in a conventional manner, and after casting with custom protector caps and pegs.
Material and Methods: Thirty implants with a standard-diameter conical connection (NobelReplace Conical Connection 4.3×13 mm; Nobel Biocare AG) and 30 premachined 4.3-mm GoldAdapt abutments (GoldAdapt; Nobel Biocare AG) were selected for this study. Specimens were divided into 3 groups (n=10): the uncast custom castable abutment group (UCCA) in which abutments were new and not cast; the unprotected custom castable abutment group (UPCCA) in which abutments were cast and devested with airborne-particle abrasion; and the protected custom castable abutment group (PCCA) in which abutments were cast by using protector caps and pegs made by milling zirconia and then devested with airborne-particle abrasion. All abutments in each group were tightened to 35 Ncm with a calibrated digital tightening device. After 10 minutes, all screws were retightened to 35 Ncm. At 3 hours, each screw was loosened, and the value at which the initial loosening occurred was documented as the RTV. The results were statistically analyzed with 1-way ANOVA to explore differences, and post hoc tests with Tukey adjustment were used for multiple comparisons.
Results: Among the tested groups, the mean RTV ranged from 19.89 Ncm to 27.19 Ncm: UCCA 27.19 Ncm, UPCCA 19.89 Ncm, and PCCA 24.24 Ncm. A significant difference was found among the tested groups (P<.05).
Conclusions: Casting procedures, especially devestment with airborne-particle abrasion, affected implant-abutment connections and the seat site of the screw. Protecting the implant connection site and the seat site of the abutment screw with protector caps and pegs prevented a significant loss of the RTV.
(Copyright © 2022 Editorial Council for The Journal of Prosthetic Dentistry. Published by Elsevier Inc. All rights reserved.)
Databáze: MEDLINE
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