The effects of repeated usage of implant drills on cortical bone temperature, primary/secondary stability and bone healing: a preclinical in vivo micro-CT study.

OBJECTIVE: The aims of the study were to evaluate the effects of new vs. used drills on cortical bone temperature, operation time, and primary/secondary stability and to assess bone healing by micro-CT. MATERIALS-METHODS: New, 50x-used and 100x-used drills at 800 rpm were used to place implants in the iliac crests of three male sheep in this experimental in-vivo animal study. A total of 36 implants (12 in each group) were placed. The temperature of the cortical bone was recorded with an infra-red thermometer, and the ISQ values at implant placement (primary stability) and at 4 weeks (secondary stability) were evaluated. The bone volume assessed by micro-CT was used to evaluate bone tissue healing. The results were statistically compared. RESULTS: The results have shown that the operation time and the cortical bone temperature increased by the usage of the drills (P<0.05) and the primary/secondary stability (ISQ values) decreased with the number of drill usage (P<0.05) The highest 2- and 3-dimensional bone volume (assessed by micro-CT) were noted for new drills group followed by 50x-used drills and 100x-used drills (p<0.05 at 4 weeks) CONCLUSION: The number of drill usage seems to be directly affecting the osseointegration process in implant surgery. Therefore, replacing the drills at certain time intervals may increase the success of implant treatment.