Department of Orthodontics, Shanghai Ninth People's Hospital, College of Stomatology, Shanghai Jiao Tong University School of Medicine, Shanghai, China.
Department of Stomatology, Tong Ren Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China.
Am J Orthod Dentofacial Orthop. 2021 May;159(5):635-643. doi: 10.1016/j.ajodo.2019.11.025. Epub 2021 Feb 12.
This retrospective clinical study aimed to evaluate the efficacy of different types of incisor movements with clear aligners in the sagittal plane.
Pretreatment and posttreatment cone-beam computed tomography (CBCT) scans were collected from 69 patients who underwent nonextraction treatment with clear aligners (Invisalign; Align Technology, San Jose, Calif). Integrated 3-dimensional models of the virtual incisor position (ClinCheck; Align Technology) and the posttreatment incisor position (from posttreatment CBCT scans) were superimposed over the pretreatment position (from pretreatment CBCT scans) using Mimics software (Materialise, Leuven, Belgium). On the basis of the location of the rotation center, incisors showing pure tipping (>10°), controlled tipping (>10°), translation (>1 mm), or torque (>10°) movements were selected. Efficacy was determined by comparing the predicted and achieved incisor movement, and differences with efficacy were analyzed using Kruskal-Wallis and Shapiro-Wilk tests (α = 0.05).
In measurements for 231 incisors, the mean efficacy of incisor movements in the sagittal plane was 55.58%. The most and least predictable movements were pure tipping (72.48%) and torque (35.21%), respectively. Labial root movement was significantly more predictable than lingual root movement, and labial movement of the mandibular incisors was significantly easier than that of the maxillary incisors. The type of tooth movement achieved was different from the type designed.
The efficacy of incisor movement in the sagittal plane using clear aligners varies with designed movement type, and labial root movement appears to be more accurate than the lingual root movement. The biomechanics of clear aligners remains to be further elucidated to achieve more predictable treatment results.
本回顾性临床研究旨在评估使用透明牙套在矢状面上进行不同类型切牙移动的疗效。
从 69 名接受透明牙套（Invisalign；Align Technology，加利福尼亚州圣何塞）非拔牙治疗的患者中收集治疗前和治疗后锥形束计算机断层扫描（CBCT）扫描。使用 Mimics 软件（比利时列日的 Materialise）将虚拟切牙位置的整合 3 维模型（ClinCheck；Align Technology）和治疗后切牙位置（来自治疗后 CBCT 扫描）叠加到治疗前位置（来自治疗前 CBCT 扫描）上。根据旋转中心的位置，选择显示纯倾斜（>10°）、控制倾斜（>10°）、平移（>1mm）或扭矩（>10°）运动的切牙。通过比较预测和实际切牙运动来确定疗效，并使用 Kruskal-Wallis 和 Shapiro-Wilk 检验（α=0.05）分析疗效差异。
在对 231 颗切牙的测量中，矢状面上切牙运动的平均疗效为 55.58%。最可预测和最不可预测的运动分别是纯倾斜（72.48%）和扭矩（35.21%）。唇侧根移动明显比舌侧根移动更可预测，下颌切牙的唇侧移动明显比上颌切牙更容易。实际实现的牙移动类型与设计的移动类型不同。
使用透明牙套在矢状面上进行切牙移动的疗效因设计的移动类型而异，唇侧根移动似乎比舌侧根移动更准确。透明牙套的生物力学仍需进一步阐明，以实现更可预测的治疗效果。
