Biomechanical behavior of two different surface treatments on dental implants with healing chambers in osteoporotic rabbits: an experimental study

The aging global population is experiencing a growing prevalence of metabolic bone diseases, particularly osteoporosis, which compromises bone quality and poses challenges for dental implant osseointegration. Despite the systemic bone fragility associated with osteoporosis, the use of implants is not contraindicated, although it may be accompanied by increased risks. Recent advances in implant macrogeometry and surface treatment aim to enhance osseointegration in compromised bone conditions. This study aimed to biomechanically and histologically evaluate the performance of dental implants featuring healing chambers and two different surface treatments in an animal model with induced osteoporosis. Twenty female New Zealand white rabbits were used, with osteoporosis induced via ovariectomy and glucocorticoid administration. A total of 80 titanium implants (two surface types: Group A – titanium oxide-blasted; Group B – titanium oxide-blasted plus HCl-conditioned) were installed in both rabbit tibiae (n = 2 implant per tibia). Stability was measured by resonance frequency analysis (RFA) and maximum removal torque. Histological assessments included bone-to-implant contact (BIC%) and bone area fraction occupancy (BAFO%) at 14- and 28-days post-implantation. RFA revealed increased implant stability over time in both groups, with Group B showing significantly higher ISQ values in 28 days (p < 0.0001). Removal torque values also improved over time, with Group B showing significantly greater values at 28 days (30.1 ± 4.18 Ncm) compared to Group A (25.6 ± 3.95 Ncm). Histomorphometric analysis showed that BAFO% was significantly greater in Group B at 28 days, but no significant differences in BIC% were observed between groups at either time point. Within the limitations of this animal model, implants with acid-etched surfaces showed improved biomechanical stability and bone occupancy at later healing stages, but only at 28 days. These results suggest that surface modifications may play a role in enhancing osseointegration over time in compromised bone environments. However, the findings are limited to this preclinical model and do not allow direct clinical extrapolation.