The effects of tooth preparation on pressure measured in the pulp chamber:A laboratory study

Purpose: The purpose of this study was to determine pressure changes in the pulp space during tooth preparation with either diamond or tungsten carbid e burs in a high-speed dental handpiece in the laboratory. Materials and Me thods: Twenty premolar teeth were collected and randomly assigned to two gr oups: group 1 received preparation with diamond burs and group 2 with tungs ten carbide burs. The teeth were mounted on a pressure transducer and the p ulp chambers were filled with saline. A 0.1-mm thickness of tooth tissue wa s removed from the proximal surface of each tooth, alternating dry and wet cutting, until the pulp chamber was exposed. Pressure and temperature chang es were recorded during tooth preparation. Results: At 0 to 1 mm of remaini ng dentin depth dry cutting with diamond and tungsten carbide burs generate d a mean positive pulpal pressure of 12 kPa and 6 kPa, respectively. Wet cu tting under the same conditions produced 0.6 kPa and 0.15 kPa, respectively . The difference between wet and dry cutting was highly significant (P < 0. 001). Diamond burs produced significantly higher pressure increases than ca rbide burs at all levels for both wet and dry techniques (P < 0.05). When c utting farther than 2 mm from the pulp, tooth preparation created a mean 0. 09-kPa pressure increase, which was not influenced by either coolant use or bur type. The temperature change was minimal during wet cutting and only m inor temperature increases were recorded during dry cutting. Conclusion: Fr om this laboratory study it is concluded that significant pressure changes occur in the pulp chamber during tooth preparation of extracted teeth when the remaining dentin thickness is less than 2 mm.