In vitro study of heat production during power reduction of equine mandibular teeth

Objective-To measure the amount of heat generated during 3 methods of equine dental reduction with power instruments. Design-In vitro study. Sample Population-30 premolar and molar teeth removed from mandibles of 8 equine heads collected at an abbatoir. Procedure-38-gauge copper-constantan thermocouples were inserted into the lingual side of each tooth 15 mm (proximal) and 25 mm (distal) from the occlusal surface, at a depth of 5 mm, which placed the tip close to the pulp chamber. Group-NC1 (n = 10) teeth were ground for 1 minute without coolant, group-NC2 (10) teeth were ground for 2 minutes without coolant, and group-C2 (10) teeth were ground for 2 minutes with water for coolant. Results-Mean temperature increase was 1.2degreesC at the distal thermocouple and 6.6degreesC at the proximal thermocouple for group-NC1 teeth, 4.1degreesC at the distal thermocouple and 24.3degreesC at the proximal thermocouple for group-NC2 teeth, and 0.8degreesC at the distal thermocouple and -0.1degreesC at the proximal thermocouple for group-C2 teeth. Conclusions and Clinical Relevance-In general, an increase of 5degreesC in human teeth is considered the maximum increase before there is permanent damage to tooth pulp. In group-NC2 teeth, temperature increased above this limit by several degrees, whereas in group-C2 teeth, there was little or no temperature increase. Our results suggest that major reduction of equine teeth by use of power instruments causes thermal changes-that may cause irreversible pulp damage unless water cooling is used.