Evaluation of cutting efficiency of orthograde ultrasonic tips by using a nonstatic model.

The purpose of this in vitro study was to evaluate the cutting efficiency of 4 orthograde ultrasonic tips and describe a nonstatic cutting model. Forty molars were extracted and decoronated. Each group contained 10 tips. The samples were fixed to a double pan balance that applied a constant vertical force of 40 g to the ultrasonic tips. The ultrasonic handpiece was mounted to a cyclic axial fatigue testing apparatus to generate a 3-mm horizontal movement of the ultrasonic tip during the cutting procedure. Three cutting cycles of 30 seconds were tested for each power setting of 3, 5, and 7. The weight of the samples was measured before and after the 3 cycles. The cutting efficiency was determined by the weight change caused by dentin removal. The Buc-1 ultrasonic tip had a significantly greater cutting efficiency than the other 3 tips at each of the 3 power settings (P < .05).