Influence of the drill material and method of cooling on the development of intrabony temperature during preparation of the site of an implant

Our aim was to evaluate the intrabony friction heat produced by implant drills, using different drill materials and methods of cooling. Four pilot drills and 4 form drills were used. The following combinations of drill material and cooling supply were tested: steel and external cooling; steel and internal cooling; steel coated with zirconium nitride and external cooling; and zirconium oxide and external cooling. The handpiece that supported the drill was fixed in a lifting device. Specimens of bovine ribs were fixed below the handpiece, and the drill speed was set to 1200 rpm. The vertical force was adjusted to 1 kg for pilot drills and 0.5 kg for implant drills. Intrabony temperature during drilling was measured at depths of 4, 8, and 12 mm parallel to the drill, and the depth was limited to 13 mm. There were no significant differences in heat generation between the drill materials (p > .05), but the differences between groups with internal or external cooling supplies were significant (p ≤ .05). The method of cooling affected the development of the intrabony temperature during preparation of the site of the implant, but the drill material seemed to play no particular role.