Comparative Analysis of Reverse Torque Values Between Customized CAD/CAM and Prefabricated Abutments and Screws: An In Vitro Study.

Abstract

Purpose: To examine and compare the mechanical success of customized CAD/CAM and prefabricated abutments and screws before and after cyclic loading by measuring removal torque values.

Materials and methods: A total of 28 dental implants with identical characteristics were divided into two equal groups. The control group comprised prefabricated abutments and screws, and the study group comprised customized CAD/CAM abutments and screws. Removal torque values (RTVs) were measured before and after 50,000 and 1 million cycles of loading in both groups. Additionally, to evaluate the screw fatigue performance, they were retightened to 30 Ncm torque and RTV measurements were repeated. The data were analyzed using a one-way analysis of variance (ANOVA), a Newman Keuls test, and a paired t-test.

Results: No significant difference was observed in RTVs before cyclic loading within each group. However, the RTVs measured before cyclic loading were found to be significantly lower in the study group compared to the control group. Both groups exhibited a significant decrease in RTV after cyclic loading. The RTV of the study group was significantly lower than the control group, especially after 1 million cycles. No significant difference was found in the screw fatigue performance of both groups.

Conclusions: The significantly lower RTVs of customized CAD/CAM abutments and screws before and after cyclic loading have raised questions about their effectiveness and widespread use. This study underscores the necessity for further clinical investigations comparing the mechanical success of custom and prefabricated abutments and screws.