Heat generated by grinding during removal of ceramic brackets

Abstract

When ceramic brackets fracture during treatment or at the time of debonding, it may become necessary to remove residual fragments by grinding with a handpiece. However, the grinding of ceramic surfaces may generate temperatures high enough to have detrimental effects on dental pulp. Intrapulpal temperature measurements were made on extracted teeth during bracket grinding with a small thermocouple probe fixed to the pulpal wall subjacent to the bracket position. These measurements were then compared with established threshold temperatures that have been reported to cause pulpal pathosis. We removed 122 ceramic brackets (A-Company Starfire, GAC Allure, and Unitek Transcend) from eight extracted teeth by grinding with high-speed diamond burs or low-speed green stones, both with and without air or water coolant. It was determined that low-speed grinding without coolant resulted in a significant (p less than 0.001) increase in pulp chamber temperature for all three types of brackets. Neither high-speed nor low-speed grinding during bracket removal caused a rise in pulp chamber temperature when combined with air or water coolant.