ABSTRACT
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.
