Providing optimum torque to implant prostheses: a pilot study

Ten N/cm torque has been proposed as the optimum level for the tightening of implant retaining gold screws in order to preload the implant components to limit loosening and fracture. The purpose of this study was to determine the influence of instrumentation and operator experience on the torque generated during manual tightening of slotted gold screws. Sixteen subjects, divided into four groups based on experience, were instructed to tighten five screws into implant analogs with 20-mm and 37-mm slotted screwdrivers. The screws were then removed with a torque gauge. All of the groups of subjects were able to generate significantly greater torque with the 37-mm screwdriver. Dentists with no implant treatment experience generated significantly less torque than the other three groups. Of the 12 dentist subjects, only 3 generated the optimal amount of torque when using the 20-mm screwdriver. Operators who had little experience dealing with implant prostheses were not able to provide the recommended torque and experienced operators tended to generate more than the recommended amount. None of the subjects were able to generate consistent torque values.