Comparison of Removal Torque Between Manual and Motor-driven Orthodontic Miniscrew Insertion

Aim To compare the maximum removal torque (MRT) of orthodontic miniscrews inserted using a manual driver versus a contra-angle motor-driven method. Material and Methods Forty self-drilling, tapered orthodontic mini-implants (8 mm length, 1.65 mm diameter) were inserted into artificial bone blocks without predrilling. Twenty were placed using a manual driver and 20 with a motor-driven contra-angle driver (40 rpm), all at a 90° angle. MRT was measured using a digital torque gauge. Statistical analysis was performed using the paired t -test ( P < .05) in International Business Machines (IBM) Statistical Package for the Social Sciences (SPSS) v24.0. Results The mean MRT was 7.46 N·cm for the manual insertion group and 6.95 N·cm for the contra-angle driver group. The difference of 0.51 N·cm was statistically significant ( P < .0001). MRT values ranged from 6.8 to 8.6 N·cm in the manual group and 6.3-7.6 N·cm in the contra-angle group. Conclusion Manual insertion yielded a higher average MRT than the contra-angle driver, with the difference being statistically significant. This suggests a potential clinical advantage of manual insertion in achieving greater primary stability.