Torque ratio as a predictable factor on primary stability of orthodontic miniscrew implants
Related Experiment Video
Updated: Apr 24, 2026

Author Spotlight: 3D Movement Assessment of Maxillary Posterior Teeth in Clear Aligner Treatment
Published on: February 23, 2024
Masahide Inoue1, Shingo Kuroda, Akihiro Yasue
1*Graduate Student, Department of Orthodontics and Dentofacial Orthopedics, The University of Tokushima Graduate School of Oral Sciences, Tokushima, Japan. †Associate Professor, Department of Orthodontics and Dentofacial Orthopedics, Institute of Health Biosciences, The University of Tokushima Graduate School, Tokushima, Japan. ‡Senior Assistant Professor, Department of Orthodontics and Dentofacial Orthopedics, The Tokushima University Hospital, Tokushima, Japan. §Professor, Department of Orthodontics, School of Dentistry, Kyungpook National University, Daegu, South Korea. ‖Professor and Chair, Department of Orthodontics and Dentofacial Orthopedics, Institute of Health Biosciences, The University of Tokushima Graduate School, Tokushima, Japan.
Objective:
To evaluate the torque ratio (TR) as a predictable factor on primary stability of orthodontic miniscrews.
Design:
Fifty-eight orthodontic patients (17 men, 41 women; mean age, 21.9 years) with a total of 112 titanium miniscrews of 3 different diameters were subjected. Maximum insertion torque (MIT) and maximum removal torque (MRT) were measured by a digital torque checker at the screw placement. Four weeks after the placement, the stable screw was recorded as a success. Multiple logistic regression analysis was performed to estimate the influence of each clinical variable on success.
Results:
Success rates were 82.1% to 89.5%, and there were no significant differences in the 3 types of miniscrews. MIT and MRT showed a positive correlation but did not affect the success rates of miniscrews directly. On the contrary, TR was significantly higher in the success group than in the failure group. In multiple regression analysis, age, TR, and screw proximity had a significant influence on the miniscrew success.
Conclusions:
TR might be related with the miniscrew success rates, and it can be used as a predictable factor on primary stability of orthodontic miniscrew implants. Miniscrew implants should be replaced if MRT is significantly lower than MIT at placement surgery.
Related Concept Videos
Screw: Problem Solving
To evaluate the...
Torque
Torque can be considered as the rotational counterpart to force. Since forces change the translational...
Residual Stresses in Circular Shafts
Stress Concentrations in Circular Shafts
Stability of structures
Angle of Twist: Problem Solving

