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

Abstract

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 (ΔΤ) was calculated by subtracting the baseline from the maximum temperature (ΔT = Tmax − Tbase). Drill design and drill diameter, as independent variables or synergistically, had a significant effect on ΔΤ. Tapered drills: As the drill diameter increased, ΔΤ increased at all RPM. Straight drills: As the drill diameter increased, ΔΤ remained constant or slightly decreased at all RPM. Drill diameter and design had a significant effect on ΔΤ in human tibiae, which never exceeded the critical threshold of 47 °C. Tapered drills caused significantly greater heat production compared to straight drills.

Temperature Changes during Implant Osteotomy Preparations in Human Cadaver Tibiae Comparing MIS® Straight Drills with Densah® Burs

“…Many studies with varying methodologies addressed the problem of heat production during implant osteotomy preparation [ 9 , 15 , 24 , 28 , 29 , 30 , 31 , 32 , 33 , 34 , 35 , 36 , 37 , 38 , 39 , 40 , 41 , 42 , 43 , 44 ]. Trisi et al described that bone temperature of 60 °C for 1 min during implant osteotomy preparations in an iliac crest sheep model, significantly reduced bone to implant contact [ 30 ].…”

“…An innovative translational model using human cadaver tibiae, previously developed by one of the authors (N.S. ), and used in a previous study, was used in the present study [ 24 ]. Human tibiae and mandibular bone, although having different origins, possess similar compressive strength and elastic modulus [ 26 ].…”

“…A temperature regulated water bath, filled with sterile saline, was maintained at a range of 95.2 °F to 99.6 °F (35.1–37.5 °C). Temperature of the saline bath and osteotomies were recorded with an oral thermometer (REF MDS9950) and K-type thermocouple (Fisher Scientific ® , Hampton, NH, USA 15-078-187, range −58 to 2000 °F, resolution 0.1°/1°, sampling rate 2.5 times per second), with an ultra-fast response naked bead probe (maximum range 260 °C), respectively ( Figure 2 ) [ 24 ]. The room temperature was kept at a constant 68 ± 1°F (20 °C).…”

“…This process was repeated following the sequential surgical protocol detailed above [ 24 ]. All values were recorded on an Excel ® spreadsheet for statistical analyses.…”

“…Preliminary studies comparing straight, and tapered implant drills found significant differences in heat generation when preparing osteotomies at 800, 1000, or 1200 revolutions per minute (RPM) [ 24 ]. While neither the straight nor tapered drills produced temperatures that exceeded the 47 °C threshold, tapered drills generated significantly higher temperatures than straight drills [ 24 ]. An innovative tapered drill has been marketed to offer a “fast feed rate with minimal heat elevation” [ 25 ].…”