Comparison of wear and temperature of zirconia and tungsten carbide tools in drilling bone: in vitro and finite element analysis.

Drilling is extensively used in operations on bones and dental implants, and yet poses a considerable challenge because it can damage cells as well as cause mechanical and thermal stresses to the bone. The goal of this study was to assess the temperature changes and instrument wear using both zirconium dioxide (ZrO) ceramics and tungsten carbide (WC) tools using a 3-dimensional finite element analysis (FEA) of bone drilling. The wear of conical burrs made from ZrO and tungsten carbide was measured using scanning electron microscopy (SEM) and image processing software. Temperature was measured by an infrared thermometer. As well as 3-dimensional FEA, the temperature and wear of the burrs was predicted with the aid of the Johnson-Cook model for bone material properties. Comparison between the ZrO and WC burrs using SEM showed that the ZrO burr was less worn than the WC burr (p = 0.044) and there was significant difference in temperature between the two (p = 0.020). We conclude that ZrO tools are a suitable alternative to WC, particularly in superficial drilling with coolant, as they wear less than the WC tools. The results of the FEA successfully predicted the variation in temperature and the wear on the tools.