Temperature Changes during Implant Osteotomy Preparations in Fresh Human Cadaver Tibiae, Comparing Straight with Tapered Drills^†

The success of osseointegration depends on many factors. With temperatures beyond a 47^◦ C threshold over 1 min, bone survival may be impaired. The purpose of the study was to evaluate, in fresh human cadaver tibiae, the temperature changes during osteotomy preparations using two straight and two tapered implant systems’ drills, external irrigation, and varying revolutions per minute (RPM). The tibiae from a fresh female cadaver were harvested bilaterally. Two tapered and two straight design drills were assessed. Two-hundred and forty osteotomies were prepared at 6 mm depth following the drill sequence of the manufacturers’ protocol for each drilling speed. Difference in temperature (∆T) was calculated by subtracting the baseline from the maximum temperature (∆T = T_max − T_base ). Drill design and drill diameter, as independent variables or synergistically, had a significant effect on ∆T. Tapered drills: As the drill diameter increased, ∆T increased at all RPM. Straight drills: As the drill diameter increased, ∆T remained constant or slightly decreased at all RPM. Drill diameter and design had a significant effect on ∆T in human tibiae, which never exceeded the critical threshold of 47^◦ C. Tapered drills caused significantly greater heat production compared to straight drills.