Accuracy of Mechanical Torque- Limiting Devices for Implants

Purpose: To examine the accuracy of 3 mechanical torque wrenches. Materials and Methods: The torque outputs of the Nobel Biocare, Straumann ITI, and DynaTorq ITL mechanical torque-limiting devices were determined using a special setup on an Instron test machine. The devices were held in the test setup and oriented so that activation of the drivers caused a pure torsion effect. Results: Significant differences generally existed between individual units and the target torque levels for the Nobel Biocare torque controller. Discussion: The mean torque values of the ITI and ITL devices were within 10% of their respective target torque levels. Knowledge of applied torque levels to the screws that retain implant abutments and their attached prostheses is necessary to achieve optimal preload. The ITI and ITL devices tested in this study were capable of providing consistent torque at or near their respective targets. Conclusion: The torque output of each individual device deviated in varying degrees from target torque values. Keywords: dental implants, mechanical devices, torque control