Determination of primary stability: a comparison of the surgeon's perception and objective measurements.

PURPOSE To evaluate the difference between the dental surgeon's perception of implant stability and the actual insertion torque and actual values obtained through resonance frequency analysis (RFA) during implant insertion surgery. MATERIALS AND METHODS One hundred fifty-two patients who needed one or more dental implants were selected. A total of 514 Xive implants was inserted. For all 514 implants, after insertion, the oral surgeon was asked to indicate the probable RFA values (implant stability quotient [ISQ]). For 483 implants, the surgeon was also asked to indicate the probable insertion torque values (N/cm). The actual values were then measured. The RFA and insertion torque values were grouped into low, medium, and high groups. RESULTS The mean perceived RFA was 72.2 +/- 9.8 ISQ. The mean actual RFA was 73.5 +/- 10.2 ISQ. This difference was statistically significant (P = .01). The mean perceived insertion torque was 39.1 +/- 20.1 Ncm. The mean actual insertion torque was 39.9 +/- 20.7 Ncm. The mean difference between actual and perceived ISQ values was -1 +/- 14.9, with a range from -60 to 59; the mean difference between actual and perceived insertion torque values was -1.3 +/- 9.9, with a range from -38 to 45. CONCLUSIONS Xive implants obtained good primary stability in many different clinical situations with a standard protocol. Primary stability is generally underestimated, especially in the presence of low or medium ISQ and torque values. The accuracy of primary stability prediction is not good enough to prevent mistakes when using an immediate loading technique; therefore, a more systematic use of objective measurements is encouraged.