Accuracy of mechanical torque-limiting devices for dental implants after clinical service.

STATEMENT OF PROBLEM: Limited information is available regarding the accuracy of mechanical torque-limiting devices (MTLDs) after their clinical use. PURPOSE: The purpose of this study was to determine the accuracy of 2 types of MTLDs (friction-style and spring-style) after clinical use. MATERIAL AND METHODS: Twenty-seven MTLDs in clinical service at The Ohio State University College of Dentistry were collected. Thirteen were friction-style and 14 were spring-style. A total of 6 different dental implant companies were represented (Astra Tech, Zimmer Dental, Biomet 3i, Straumann, Nobel Biocare, and Thommen Medical). All MTLDs had been in use for at least 6 months without being recalibrated, and all were tested to determine their accuracy in delivering target torque values. Statistical analysis used nonparametric tests to determine the accuracy of the MTLDs in delivering target torque values, and Bonferroni post hoc tests were used to assess pairwise comparisons. RESULTS: After clinical service, spring-style MTLDs were significantly more accurate than friction-style MTLDs (P<.05). CONCLUSIONS: Within the limitations of this study, it was concluded that after clinical service, spring-style MTLDs were more accurate than friction-style MTLDs. All MTLDs delivered torque values within 10% of the target torque value.