Chen G, Chen S, Zhang X Y, Jiang R P, Liu Y, Shi F H, Xu T M
Department of Orthodontics, Peking University School and Hospital of Stomatology, Beijing, China.
Key Lab of Machine Perception, MOE, Peking University, Beijing, China.
Orthod Craniofac Res. 2015 Aug;18(3):125-33. doi: 10.1111/ocr.12065. Epub 2015 Feb 19.
To evaluate the positional stability of miniscrews during orthodontic treatment change in cone-beam computed tomography (CBCT).
Twenty adult volunteers were enrolled.
In all participants, at least two maxillary first premolars were extracted because of protrusion. Each volunteer received six miniscrews in the maxilla, including two loaded miniscrews to retract anterior teeth and four unloaded miniscrews. CBCT scans were obtained at the beginning of space closure (T1) and approximately 11.8 months later (T2). Three-dimensional miniscrew models were constructed at T1 and T2, and the central axes were calculated using a principal component analysis (PCA) technique. Finally, we measured and compared the angle change of all the miniscrews from T1 to T2.
The angle change values of the unloaded and loaded miniscrews were 1.64 ± 1.25° and 1.67 ± 1.15°, respectively. No significant differences in the angle change were observed.
Cone-beam computed tomography images revealed both the unloaded and loaded miniscrews to be positionally stable during en-masse retraction in this study.
通过锥形束计算机断层扫描（CBCT）评估正畸治疗过程中微螺钉的位置稳定性。
招募了20名成年志愿者。
所有参与者因牙列前突至少拔除两颗上颌第一前磨牙。每位志愿者在上颌植入六颗微螺钉，其中两颗用于牵引前牙的加载微螺钉，四颗未加载微螺钉。在间隙关闭开始时（T1）和大约11.8个月后（T2）进行CBCT扫描。在T1和T2构建三维微螺钉模型，并使用主成分分析（PCA）技术计算中心轴。最后，测量并比较所有微螺钉从T1到T2的角度变化。
未加载和加载微螺钉的角度变化值分别为1.64±1.25°和1.67±1.15°。未观察到角度变化有显著差异。
在本研究中，锥形束计算机断层扫描图像显示，在整体内收过程中，未加载和加载的微螺钉位置均稳定。
