Effect of viewing angle and activation speed of various torque wrenches: A comparative evaluation of accuracy and...

The loosening of abutments is one of the most frequent complications of implant-supported restorations.

The purpose of this study was to compare the accuracy and performance of different dental torque wrenches in achieving the target torque values.

A spring-type (NTA Implant; Pilatus Swiss Dental GmbH), friction-type (NTA Implant; Pilatus Swiss Dental GmbH), and single-value torque wrench (Dentsply Sirona) were used. The implants included 4 NTA implants (Ø4.2×10 mm) (NTA Implant; Pilatus Swiss Dental GmbH) and 1 Frialit implant (Ø4.5×13 mm) (XiVE; Dentsply Sirona) with corresponding standard cement-retained abutments. Torque measurements were recorded using a digital torque gauge (MTT03-12; Mark-10 Co.), and torque was measured at different viewing angles using a digital angle finder (Neoteck). A total of 339 torque applications were made, including 9 torques per time-dependent and independent experimental group and 50 torques per clinician's viewing angle experimental group.

In time-independent tests, the friction-type torque wrench (Type B) generated the highest mean ±standard deviation torque value (32.1 ±0.9 Ncm), while the single-torque-value wrench (Type C) produced the lowest mean ±standard deviation torque value (23.5 ±0.4 Ncm). In time-dependent tests, the mean torque values generated during slow torque application (>4 seconds) were higher than those generated during fast torque application (1 to 4 seconds). Regarding the clinician's viewing-angle evaluation, the spring-type wrench (Type A) produced the highest torque values at 90 degrees, moderate values at 60 degrees, and the lowest at 30 degrees.

Torque application conditions, such as speed and angle, significantly influenced measurement accuracy. The friction-type wrench produced the highest torque values, whereas the spring-type wrench exhibited greater repeatability. All mean torque values were within ±10% of the target values. To achieve the best results when using spring-type wrenches, the clinician's viewing angle should be 90 degrees. In clinical applications, the adverse effects of rapid torque tightening and angle variations on accuracy should be considered. These results provided insight into the selection of devices and protocols for accurate torque application for dental implants.