Comparative evaluation of spring-loaded torque wrench with that of friction loaded - An in vitro study in animal bone

Abstract

Aim: This study aims to determine the efficacy of commercially available spring loaded manual torque wrenches with that of friction loaded manual torque wrenches. Materials and Methods: Two spring loaded torque wrenches (MIS and the other Ospal) and two, friction loaded (Nobel Biocare and Myraid). Four implants of the same size and diameter of one company (MIS 4.2 mm × 13 mm) was used in the study. Femur bone of sacrificed goat and a dummy mandible made of polycarbonate were used. All four implants were placed once in femur bone of goat, and similarly in dummy mandible. Removal torque analysis was calibrated using these four torque wrenches. In Stage I, all four implants were placed on polycarbonate of mandible by following standard drilling protocol as prescribed by the manufacturer. All four implants were placed in goat bone in Stage II. Then, all four implants were removed from both polycarbonate of mandible and goat bone using four different torque wrench and removal torque analysis was recorded. The procedure was repeated 5 times each. Results: The data obtained had a significant difference between the spring loaded and friction loaded torque wrenches and reading obtained from friction loaded (Nobel Biocare, Myraid) torque was consistent compared to spring loaded (Ospal, MIS). The data obtained from spring loaded torque wrench showed much variables.Conclusion: Our results indicate that friction loaded torque wrenches produce more accurate results compared to spring loaded torque wrenches.