Effect of adding a peak marker device to an implant cantilever beam torque wrench on torque value measurement

An implant cantilever beam torque wrench (ICBTW) must be accurate and precise when delivering torque. Any hinderance to its action may have a detrimental effect. A marker device has been proposed as a means of recording the peak torque value of implant screw assembly when using an ICBTW. However, its impact on the torque delivered to the screwdriver along with friction-induced resistance remains unknown.

The aim of this in vitro study was to evaluate the effect of attaching the marker device on torque delivery by testing various ICBTWs with and without the device and comparing the torque values transmitted to the screwdriver.

Four calibrated ICBTWs from 2 manufacturers (Nobel BioCare and Straumann) were connected to their respective screwdrivers and to a calibrated electronic torque measuring device (Imada HTG2-4). The nonfixed end of each cantilever beam was attached to a force gauge (Shimpo FGV-5XY) with an initial crosshead speed of 50 mm/minute and a jogging action of 5 mm/minute. The applied force was recorded when the torque value reached 35 Ncm. For each torque wrench system, 15 measurements were performed with the polyolefin marker device and 15 without the marker device. Statistical analysis consisted of the paired correlated sample t test (α=.05).

All paired measurements remained highly consistent. Mean differences were within the measurement error of the force gauge (±0.01 N), indicated that adding the marker device did not affect the torque wrench performance at 35 Ncm (P>.999).

Adding a marker device to the cantilever beam torque wrench can help record reproducible peak torque values without any loss of accuracy or precision.