Effect of handpiece pressure and speed on intrapulpal temperature rise

This study determined the effect of handpiece pressure and speed on the intrapulpal temperature rise produced during finishing. Finishing was performed on a class V amalgam restoration with a brown rubber point. The remaining dentin thickness was standardized under the restoration at 2.0 mm. Finishing was done continuously for 60 seconds with temperature rises recorded at the dentin/pulp interface every 15 seconds. All finishing was done dry. Handpiece speed (rpm's) varied from 7000-15,000 rpm's and applied pressure from 20-60 gr force. Increases in either speed or pressure can produce significant intrapulpal temperature increases over these ranges. Doubling either one produces a 50% temperature increase during finishing. Finishing at 15,000 rpm's with 60 gr force is capable of producing damaging temperature rises at the pulp after only 15 seconds finishing time.