Comparative Analysis of Surface Roughness and Design Features of Titanium Dental Implants on Primary Stability and Osseointegration

Objective: This study aimed to evaluate the impact of the surface roughness and design features of titanium dental implants on primary stability and osseointegration. Methods: Sixty titanium dental implants were categorized into three groups based on their surface roughness: smooth (Subgroup A1), moderately rough (Subgroup A2), and highly rough (Subgroup A3). Each roughness category was further divided into three design subgroups: cylindrical (B1), tapered (B2), and hybrid (B3). Primary stability was assessed using insertion torque and resonance frequency analysis (RFA). Osseointegration was evaluated through histological and histomorphometric analyses, measuring bone-to-implant contact (BIC) and bone area fraction occupancy (BAFO) at 4, 8, and 12 weeks post-implantation in rabbit models. Results: Highly rough-surface implants (Subgroup A3) demonstrated significantly higher insertion torque and ISQ values than smooth (Subgroup A1) and moderately rough (Subgroup A2) implants (P < 0.001). Among the design features, tapered implants (Subgroup B2) exhibited the highest insertion torque and ISQ values (P < 0.001). Histological and histomorphometric analyses revealed that highly rough-surface implants (Subgroup A3) and tapered implants (Subgroup B2) had the highest BIC and BAFO percentages at all time points (P < 0.001). Conclusion: These findings indicate that both surface roughness and implant design significantly influence primary stability and osseointegration.