Manual closing torque in five implant abutment systems: An in vitro comparative study

Statement of problem. A significant percentage of abutment/implant (A/I) as semblies tend to unscrew on functional loading. Purpose. This in vitro study evaluated the maximum closing torque generated manually for comparison with recommended closing torque values in 5 implan t systems. Methods. Closing torque generated by 9 operators with 5 manual torque drive rs was measured and compared by using a mannequin and torque gauge assembly . Results. Closing torque values were found to be significantly different bet ween operators and between implant systems (P<.0001). Mean closing torque v alues of 9 operators performing 5 closures for 5 systems ranged from 7 to 1 4.6 N/cm for habitual closures and from 9.4 to 19.9 N/cm for maximum closur es. Conclusions. The results demonstrated that maximum manual closure did not a pproach recommended closing torque in any of the system measured. Significa nt interoperator and intraoperator variability was found in the closing tor que with manual drivers, and the driver diameter and grip were probably an important feature in the generation of high closing torque.