Department of Orthodontics, the Affiliated Stomatological Hospital of Nanjing Medical University; Jiangsu Key Laboratory of Oral Diseases, Nanjing Medical University; Jiangsu Province Engineering Research Center of Stomatological Translational Medicine, Nanjing, China.
Department of Orthodontics, the Affiliated Stomatological Hospital of Nanjing Medical University, Nanjing, China.
Am J Orthod Dentofacial Orthop. 2023 Apr;163(4):509-519. doi: 10.1016/j.ajodo.2022.02.015. Epub 2022 Oct 27.
This retrospective clinical study investigated the clinical changes of maxillary central incisor and alveolar bone in Class II Division 2 nonextraction treatment with fixed appliances or clear aligners on the basis of cone-beam computed tomography.
Fifty-nine Chinese Han patients with similar demographic characteristics were collected from a conventional bracket group, a self-ligating bracket group, and a clear aligner group. All measurements about root resorption and alveolar bone thickness on the cone-beam computed tomography images were tested. Changes between pretreatment and posttreatment were evaluated by paired-sample t test. The variation among the 3 groups was compared by 1-way analysis of variance.
The resistance center of the maxillary central incisor showed upward or forward movement, and the axial inclination was increased in 3 groups (P <0.0001). Root volume loss in the clear aligner group (23.68 ± 4.82 mm) was significantly less than that in the fixed appliances group (28.24 ± 6.44 mm in the conventional bracket group, 28.17 ± 6.07 mm in the self-ligating bracket group) (P <0.05). All 3 groups showed a significant decrease in palatal alveolar bone and total bone thickness at all 3 levels at posttreatment. In contrast, labial bone thickness significantly increased except for crestal level l. Among the 3 groups, the clear aligner group had a prominent increase in labial bone thickness at the apical level (P = 0.0235).
Clear aligner treatment for Class II Division 2 malocclusions could effectively reduce the incidence of fenestration and root resorption. Our findings will be beneficial to comprehensively understand the effectiveness of different appliances for Class II Division 2 malocclusions treatment.
本回顾性临床研究基于锥形束 CT，调查了固定矫治器和透明牙套在不拔牙治疗 II 类 2 分类错颌中的上颌中切牙和牙槽骨的临床变化。
从传统托槽组、自锁托槽组和透明牙套组中收集了 59 名具有相似人口统计学特征的中国汉族患者。所有关于根吸收和锥形束 CT 图像上牙槽骨厚度的测量值均进行了测试。采用配对样本 t 检验评估治疗前后的变化。通过单因素方差分析比较 3 组之间的差异。
上颌中切牙的阻力中心呈向上或向前运动，轴向倾斜度在 3 组中均增加（P<0.0001）。透明牙套组（23.68±4.82mm）的牙根体积损失明显少于固定矫治器组（传统托槽组 28.24±6.44mm，自锁托槽组 28.17±6.07mm）（P<0.05）。所有 3 组在治疗后所有 3 个水平的腭侧牙槽骨和总骨厚度均显著减少。相反，除了牙槽嵴顶水平外，唇侧骨厚度显著增加。在 3 组中，透明牙套组根尖水平的唇侧骨厚度增加显著（P=0.0235）。
透明牙套治疗 II 类 2 分类错颌可以有效降低开窗和根吸收的发生率。我们的研究结果将有助于全面了解不同矫治器治疗 II 类 2 分类错颌的有效性。
