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Purpose: This study evaluated and compared bone heating, drill deformation, and drill roughness after several implant osteotomies in the guided surgery technique and the classic drilling procedure., Materials and Methods: The tibias of 20 rabbits were used. The animals were divided into a guided surgery group (GG) and a control group (CG); subgroups were then designated (G0, G1, G2, G3, and G4, corresponding to drills used 0, 10, 20, 30 and 40 times, respectively). Each animal received 10 sequential osteotomies (5 in each tibia) with each technique. Thermal changes were quantified, drill roughness was measured, and the drills were subjected to scanning electron microscopy., Results: Bone temperature generated by drilling was significantly higher in the GG than in the CG. Drill deformation in the GG and CG increased with drill use, and in the CG a significant difference between G0 and groups G3 and G4 was observed. In the GG, a significant difference between G0 and all other groups was found. For GG versus CG, a significant difference was found in the 40th osteotomy. Drill roughness in both groups was progressive in accordance with increased use, but there was no statistically significant difference between subgroups or between GG and CG overall., Conclusion: During preparation of implant osteotomies, the guided surgery technique generated a higher bone temperature and deformed drills more than the classic drilling procedure. The increase in tissue temperature was directly proportional to the number of times drills were used, but neither technique generated critical necrosis-inducing temperatures. Drill deformation was directly proportional to the number of times the drills were used. The roughness of the drills was directly proportional to the number of reuses in both groups but tended to be higher in the GG group.

Purpose: The purpose of this study was to evaluate the influence of reusing high-resistance drills on bone heating, immediate bone cell viability, and drill wear after performing implant osteotomies in rabbit tibias., Materials and Methods: Two hundred sequential implant osteotomies were created in the superior tibial cortex of 12 White male rabbits. Six groups were established (G1 to G6) according to the number of osteotomies performed with each drill (0, 10, 20, 30, 40, and 50). Drilling began with a spear drill, followed by 2.0-mm, 2.8-mm, 3.0-mm, and 3.15-mm helical drills. The receptor beds were collected for immunohistochemical analysis, thermal changes were quantified, and the drills were subjected to scanning electron microscopy analysis., Results: A high degree of correlation between drill wear and number of osteotomies was observed (Pearson correlation coefficient, r = 0.984). Spear drills underwent twice as much deformation as helical drills. The bone heating analysis concluded that there was no statistically significant relationship between the number of osteotomies and bone heating (P > .05), but there were greater thermal changes during drilling with the spear drill than during drilling with helical drills (ratio 3:1). Immunohistochemical analysis showed a physiologic balance of osteoprotegerin and RANKL (receptor activator of nuclear factor κB ligand) immunolabeling in all groups; however, there was greater immunolabeling of all proteins in group G6 (50 osteotomies)., Conclusions: The tested drills did not cause significant bone heating after being reused 50 times; however, they caused more tissue trauma in the 50th osteotomy. Worn drills that are reused may be expected to cause excessive damage to the bone tissue and could adversely affect the osseointegration process.

Purpose: The aim of this study was to evaluate bone regeneration in bone cavities filled with particulate autogenous bone either harvest in blocks and subjected to milling procedures or collected during osteotomy with implant burs., Materials and Methods: In 12 rabbits, 3 noncritical unicortical cavities 7 mm in diameter were prepared with a trephine drill on the right tibia. The cavities were filled respectively with particulate autogenous bone achieved with a manual bone crusher (particulate group), with particulate autogenous bone obtained using bone collector during osteotomy (collected group), and with blood clot (control group). Animals were sacrificed at 7, 15, and 30 days after surgery (4 animals for each time period). The sections were examined by histologic and histomorphometric analysis., Results: At 7 days, the samples were filled by coagulum, and bone particles were observed only in the collected (24%) and particulate groups (44.75%). At 15 days, there was connective differentiation in all groups, with presence of grafted bone particles and onset of newly formed bone in the collected (38.88%) and particulate groups (46.0%). At 30 days, there was bone fill (immature trabecular bone) of the cavities in the control (50%), collected (64.63%) and particulate groups (66%)., Conclusion: No significant difference was demonstrated between noncritical unicortical bone defects in rabbit tibiae filled with particulate bone harvested as a block and subjected to milling and those filled with bone collected during osteotomy with implant drills when the defects were observed up to 30 days following their creation.