Original vs. non-original abutments for screw-retained single implant crowns: An in vitro evaluation of internal fit, mechanical behaviour and screw loosening.

Abstract

To assess the internal accuracy, mechanical behaviour under static load and screw loosening before and after cyclic loading of implant-supported crowns restored with original components or with two compatible non-original brands. Sixty-three dental implants were divided into three groups (n=21 each): Group 1 used original components, and groups 2 and 3 used non-original components. Internal accuracy was measured throughout a cross section of the sample groups (n=8) using scanning electron microscopy (SEM) to evaluate the fit for implant-abutments, implant-crowns and crown-abutments. To evaluate load-bearing capacity, eight samples from each group were loaded until fracture according to ISO Norm 14801. The removal torque value (RTV) was evaluated in the screws connecting the crown with the abutment and the abutment with the implant before and after cyclic loading (2x106 cycles) in five samples from each group. The data were analysed using the Kruskal-Wallis test (p<0.05). Statistically significant differences were found among the mean crown-abutment gaps measured in Group 1 (9.3μm), Group 2 (45.4μm) and Group 3 (44.9μm). Higher values for mean load-bearing capacity were found in Group 1 (1,098N) than in groups 2 and 3 (1,057 and 973N, respectively); however, these differences were not statistically significant. Original abutment-implant screws exhibited lower percentages of torque reduction than the non-originals. Enhanced fit is expected when original components are used. The original abutments exhibited lower percentages of torque reduction after cyclic loading than non-originals.