Avaliação clínica e radiológica de diferentes designs de componentes protéticos para conexões cone morse e haxágono externo: um ensaio clínico randomizado de boca dividida com acompanhamento de 3 anos

Abstract

The configuration of prosthetic components can exert a significant influence on the remodeling behavior of the marginal bone around osseointegrated implants. However, there is still a scarcity of comparative clinical evidence investigating the combined effect between the type of prosthetic connection and the component design. Thus, this splitmouth randomized clinical trial aimed to analyze the impact of the interaction between the prosthetic abutment design and the connection type on marginal bone remodeling, both vertically (vMBL) and horizontally (hMBL), in implant-supported prostheses placed in the mandible, after a 3-year follow-up period. Fourteen individuals participated in the study, totaling 64 implants placed in premolar and molar regions. Each hemiarch received at least two implants — one with a Morse taper connection (MT) and another with an external hexagon connection (EH) with different prosthetic component designs assigned: platform switching (PS) or platform matched (PM). In this way, four experimental combinations were formed: MT+PS, MT+PM, EH+PS, and EH+PM. Standardized digital periapical radiographs were taken at specific time intervals: immediately after prosthetic installation (T1), at 3 months (T2), and after 3 years (T3), using an individually fabricated acrylic resin positioning device to ensure image reproducibility. Statistical analysis involved a threeway repeated measures ANOVA and Tukey’s HSD post hoc test for vMBL, as well as Mann-Whitney and Friedman nonparametric tests for hMBL (α = 0.05). The results showed that vertical marginal bone loss was significantly higher for the EH+PS combination compared with MT+PS (P < 0.05), and also higher for MT+PM than for MT+PS (P < 0.05). A significant increase in horizontal marginal bone loss over time was also observed for the MT+PS group (P = 0.009). The vMBL showed significantly higher values for the EH+PS combination compared with MT+PS (P < 0.05) and was also higher for MT+PM compared with MT+PS (P < 0.05). A significant increase in hMBL was observed in the MT+PS group throughout the follow-up period (P = 0.009). Overall, the MT+PS combination demonstrated superior performance compared to EH+PS regarding vMBL preservation. On the other hand, the PM component design was not effective in protecting the MT connection against vertical marginal bone loss, and the hMBL associated with the MT+PS combination showed a significant progression over time.