Evaluation of the Effect of Different Drilling Systems on Trabecular Bone Microarchitecture During Implant Cavity Preparation Using CBCT: Ex Vivo Study

PURPOSE: Achieving optimal primary stability is critical for dental implant success, particularly in low-density bone regions such as the posterior maxilla. Conventional high-speed drilling with irrigation may remove vital bone fragments and impair trabecular architecture. A novel implant-specific drilling protocol introduces a low-speed, irrigation-free approach designed to preserve bone structure and promote healing. This ex-vivo study aimed to evaluate the morphometric effects of conventional and implant-specific drilling protocols using cone beam computed tomography (CBCT). MATERIALS AND METHODS: Fifty-eight osteotomy sites were prepared in fresh bovine ribs (Type IV bone). Twenty-nine sites were drilled using a conventional protocol (high-speed, irrigated) and 29 with the implant-specific drilling protocol (low-speed Osseoshaper, no irrigation). CBCT scans were taken after the use of the pilot drill and again after the final drill in both groups. Trabecular bone microarchitecture was assessed using ImageJ software with the BoneJ plugin, analyzing bone volume fraction (BV/TV), trabecular thickness (Tb.Th), degree of anisotropy (DA), and connectivity density (Conn.D). Statistical comparisons were performed using appropriate parametric and non-parametric tests (p<0.05). RESULTS: No significant differences in DA or Tb.Th were observed between groups after drilling (p > 0.05), although both increased significantly from baseline within groups (p < 0.001). BV/TV showed a slight but statistically significant increase post-drilling in both groups (p = 0.001), with no significant intergroup difference in delta values (p = 0.107). Conn.D exhibited a non-significant upward trend in the experimental group (median = 0.105) versus a slight decrease in the conventional group (median = -0.015), with a p-value of 0.078. CONCLUSION: Within the limitations of this ex-vivo model, implant-specific low-speed drilling demonstrated no statistically significant advantage over conventional techniques in preserving trabecular bone microarchitecture. Although slight differences were observed in certain parameters, these did not reach statistical significance and should be interpreted with caution. CBCT-based 3D morphometric analysis proved to be a practical and artifact-free method for evaluating bone quality changes following site preparation, offering insights for future research on implant site preparation in low-density bone.