The Overuse of the Implant Motor: Effect on the Output Torque in Overloading Condition

Background: The overloading of the motor affects its performance. The output torque of the implant motor under overloading condition has not been reported. Purpose: The purpose of this study was to determine the reliability and the tendency of the output torque when an implant motor is consecutively used. Materials and Methods: Three implant motors were evaluated: SurgicXT/X-SG20L (NSK), INTRAsurg300/CL3-09 (KaVo), and XIP10/CRB26LX (Saeshin). The output torque was measured using an electronic torque gauge fixed with jigs. For the 40 and 50Ncm torque settings, 300 measurements were taken at 30rpm. Repeated measures of analysis of variance (ANOVA) and one-way ANOVA were used to compare the torque values within each group and between the groups. Results: As repeating measures, the output torque values decreased gradually compared with the baseline. In within-group analysis, the different torque value from the first measurement appeared earliest in NSK motor, followed in order by Saeshin and KaVo motors. NSK motor showed a different torque decrease between 40 and 50Ncm settings (p<.05). Intergroup analysis revealed Saeshin motor to have the least deviation from the baseline, followed by KaVo motor. NSK motor had the most inconsistent torque at the 6, 8, 9, and 10 repeat counts (p<.05). Conclusion: The actual torque decreases when the surgical motor is continuously used. The NSK motor showed more significant decreases in torque than KaVo and Saeshin motors in overloading condition.