TEMPERATURE RESPONSE IN THE PULPAL CHAMBER DURING ULTRAHIGH-SPEED TOOTH PREPARATION WITH DIAMOND BURS OF DIFFERENT GRIT

Statement of problem. Ultrahigh-speed tooth preparation can traumatize the hard dental tissues and the dental pulp. Purpose. This in vitro s tudy examined the relationship between different grits of diamond burs on the: temperature response within a pulpal chamber during tooth pre paration with a turbine. Material and methods. Newly extracted, undama ged third molars were secured by a rapid-tensioning device mounted on an air-supported slide. NiCrNi thermocouples were inserted apically an d used to determine the temperature within a pulpal chamber. The grind ing tests used cylindrical fine, coarse, and ultracoarse diamond burs. Results. The maximal temperature elevation within the pulp was 3.2 de grees C, and the most pronounced rise in temperature occurred with ult racoarse burs. Temperature increases in the pulpal chambers and grindi ng times or temperatures of the cooling water were approximately propo rtional. Residual dentinal thickness was inversely proportional to tem perature elevation within the pulpal chamber. Conclusions. This study demonstrated that coarse diamond burs resulted in more pronounced temp erature 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 degrees C and 32 degrees C was confirmed. A cooling temperature of 38 degrees C to 43 degrees C did not afford actual cooling.