Temperature response in the pulpal chamber during ultrahigh-speed tooth preparation with diamond burs of different grit

Abstract

Statement of problem. Ultrahigh-speed tooth preparation can traumatize the hard dental tissues and the dental pulp. Purpose. This in vitro study examined the relationship between different grits of diamond burs on the temperature response within a pulpal chamber during tooth preparation with a turbine. Material and methods. Newly extracted, undamaged third molars were secured by a rapid-tensioning device mounted on an air-supported slide. NiCrNi thermocouples were inserted apically and used to determine the temperature within a pulpal chamber. The grinding tests used cylindrical fine, coarse, and ultracoarse diamond burs. Results. The maximal temperature elevation within the pulp was 3.2° C, and the most pronounced rise in temperature occurred with ultracoarse burs. Temperature increases in the pulpal chambers and grinding times or temperatures of the cooling water were approximately proportional. Residual dentinal thickness was inversely proportional to temperature elevation within the pulpal chamber. Conclusions. This study demonstrated that coarse diamond burs resulted in more pronounced temperature increases within the pulpal chamber during tooth preparation. In addition, the benefit of short intervals between grinding steps and a cooling water temperature between 30° C and 32° C was confirmed. A cooling temperature of 38° C to 43° C did not afford actual cooling. (J Prosthet Dent 1998;80:12-9.)