Correlation Between Insertion Torque and Survival Rates in Immediately Loaded Implants in the Maxilla

Abstract

To evaluate the correlation between insertion torque and the survival rate of immediately loaded implants placed in the maxilla. 390 NobelReplace (Nobel Biocare USA, Yorba Linda, CA) Select Tapered implants were placed in the maxillae of 145 patients over a 15-month period. The insertion torque was measured using a digital torque wrench. Of the 390 implants, only 9 (2.3%) failed. The 381 successful implants were placed with an average insertion torque of 72.1 N.cm. Insertion torque values of failed implants varied between 45.8 and 134 N.cm, with an average of 69.2 N.cm. Of the 9 failed implants, 8 were abutments in multiple-unit implant-supported prostheses, and 1 was a single-unit implant. Although insertion torque undoubtedly plays an important role in the primary stability and successful osseointegration of implants, there seems to be no correlation between insertion torque and implant failure above 35 N.cm threshold of insertion torque. Immediate loading of implants in the maxilla is a successful and predictable treatment option with failure rates approaching those of traditional 2-stage surgery.