Inoue Masahide, Kuroda Shingo, Yasue Akihiro, Horiuchi Shinya, Kyung Hee-Moon, Tanaka Eiji
*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.
Implant Dent. 2014 Oct;23(5):576-81. doi: 10.1097/ID.0000000000000138.
To evaluate the torque ratio (TR) as a predictable factor on primary stability of orthodontic miniscrews.
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.
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.
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.
评估扭矩比（TR）作为正畸微螺钉初始稳定性的一个可预测因素。
对58例正畸患者（17名男性，41名女性；平均年龄21.9岁）植入总共112颗3种不同直径的钛微螺钉。在螺钉植入时，用数字扭矩测试仪测量最大插入扭矩（MIT）和最大取出扭矩（MRT）。植入后4周，记录稳定的螺钉为成功。进行多因素逻辑回归分析以评估各临床变量对成功的影响。
成功率为82.1%至89.5%，3种类型的微螺钉之间无显著差异。MIT和MRT呈正相关，但未直接影响微螺钉的成功率。相反，成功组的TR显著高于失败组。在多因素回归分析中，年龄、TR和螺钉间距对微螺钉的成功有显著影响。
TR可能与微螺钉成功率相关，可作为正畸微螺钉种植体初始稳定性的一个可预测因素。如果在植入手术时MRT显著低于MIT，则应更换微螺钉种植体。
