In vitro retentive strength of metal superstructures cemented to solid abutments
Rappelli, G.; Corso, M.; Coccia, E.; Camaioni, E.; Di Felice, R.; Procaccini, M.
Minerva Stomatologica 57(3): 95-101
2008
ISSN/ISBN: 0026-4970 PMID: 18427377 Document Number: 621863
The aim of this study was to evaluate the effect of sandblasting on the retentive strength of metal single crowns luted with a resin cement to Straumann implant/abutment assemblies. Fifty 4.1 mm-wide Straumann solid screw implants were mounted in self-polymerizing soft resin. Standard 5.5 mm-high, 8 degree tapered solid abutments were placed on each implant and torqued to 35 Ncm. Fifty metal castings were made using prefabricated burn-out caps. Each implant/abutment assembly and its corresponding metal casting was numbered and they were divided into two groups of 25. In the test group, the external surface of the abutments and the cavosurface of the corresponding metal casting were sandblasted. In the control group, neither the implant abutment nor the metal casting underwent sandblasting. Each metal casting was cemented onto its respective implant/abutment assembly using Panavia 21 (Kuraray Europe GmbH, Dusseldorf, Ger-many) resin cement. Specimens were then subjected to a pull-out test using a universal Instron testing machine. The load required to dislodge each crown was recorded and mean values were calculated for each group. Retention values were analyzed using the ANOVA test. The test group showed a higher mean retention value (83.78 kgf+/-19.61) than the control group (44.03 kgf+/-9.45) and the difference was statistically significant. Within the limitations of this in vitro study, the results suggest that sandblasting treatment significantly increases mechanical retention of crowns cemented using a resin cement. It is at the clinician's discretion to evaluate whether additional retention is desired in cementing an implant-supported fixed partial denture.