The Effects of Multiple Use and Sterilization on the Accuracy of Readings of Different Types of Torque Controllers

Application of the appropriate torque in implant prosthodontics is very important from a clinical perspective. In implant prosthodontics, three basic types of torque wrenches are used. There are few reports in the dental literature on the possibility of controlling the torque generated by the wrench. The aim of this study was to determine the precision of measurements of various types of torque wrenches after the specified number of application and sterilization cycles. The materials consisted of 22 torque wrenches (10 spring-type, 6 toggle-type, and 6 contra-angle-type). The research methodology included measuring the accuracy of torque value indications using the gravity method. The research was conducted for different torque ranges for brand new wrenches and after 50 and 100 sterilization cycles. After each sterilization cycle, the wrenches were used to generate torque several times. Results: Before sterilization, the spring-type torque controllers were characterized by the lowest accuracy (in the largest range at low torque). The average deviation for contra-angle-type and toggle-type wrenches was smaller. After sterilization cycles, the toggle-type wrenches showed the smallest changes in measurement precision. Conclusions: The effects of multiple use and sterilization on the accuracy of readings of different types of torque controllers seem limited overall; the greatest stability of measurement accuracy was demonstrated by the toggle-type wrenches, while the spring-type wrenches presented the greatest decrease in measurement precision.