Abstract：
OBJECTIVE: To evaluate alveolar bone dimensions and its relationship with tooth movement (retraction, intrusion and torque) during orthodontic treatment with fixed appliance and clear aligners.
METHODS: Thirty-two patients were included in this retrospective clinical study. Cone beam computed tomography (CBCT) was collected before and after treatment to measure the volume of dehiscence and fenestrations in the maxillary anterior region, anterior alveolar bone thickness and height and degree of tooth movement. Rank-sum tests were used to compare the differences in alveolar bone defect volumes between clear aligners and fixed appliance, multiple linear regression analysis was used for study evaluation, and kappa statistics were used to assess internal consistency and test-retest reliability.
RESULTS: Post-operatively, most alveolar bone defects occurred on the labial side. The incidence of bone fenestration was 23.96% in the clear aligner group and 26.18% in the fixed appliance group, which was higher than the incidence of bone dehiscence (5.21%). The labial bone height decreased by 0.272 mm, and the palatal bone height increased by 0.617 mm for every 1 mm downward intrusion of the anterior tooth apex in the fixed appliance group. In the clear aligner group, there was no significant change in the labial bone height, and the palatal bone height decreased by 0.447 mm for every 1 mm of anterior tooth retraction coronally.
CONCLUSIONS: In the fixed appliance group, anterior tooth intrusion and retraction may have led to alveolar bone resorption by its compression at the cervical level. This study provides a three-dimensional tooth movement evaluation method by using CBCT.
METHODS: Thirty-two patients were included in this retrospective clinical study. Cone beam computed tomography (CBCT) was collected before and after treatment to measure the volume of dehiscence and fenestrations in the maxillary anterior region, anterior alveolar bone thickness and height and degree of tooth movement. Rank-sum tests were used to compare the differences in alveolar bone defect volumes between clear aligners and fixed appliance, multiple linear regression analysis was used for study evaluation, and kappa statistics were used to assess internal consistency and test-retest reliability.
RESULTS: Post-operatively, most alveolar bone defects occurred on the labial side. The incidence of bone fenestration was 23.96% in the clear aligner group and 26.18% in the fixed appliance group, which was higher than the incidence of bone dehiscence (5.21%). The labial bone height decreased by 0.272 mm, and the palatal bone height increased by 0.617 mm for every 1 mm downward intrusion of the anterior tooth apex in the fixed appliance group. In the clear aligner group, there was no significant change in the labial bone height, and the palatal bone height decreased by 0.447 mm for every 1 mm of anterior tooth retraction coronally.
CONCLUSIONS: In the fixed appliance group, anterior tooth intrusion and retraction may have led to alveolar bone resorption by its compression at the cervical level. This study provides a three-dimensional tooth movement evaluation method by using CBCT.
摘要：
目的：评估牙槽骨尺寸及其与牙齿移动的关系（缩回，侵入和扭矩）在使用固定矫治器和清晰的矫正器进行正畸治疗期间。
方法：这项回顾性临床研究包括32例患者。治疗前后收集锥形束计算机断层扫描（CBCT），以测量上颌前区的裂开和开窗的体积，前牙槽骨厚度、高度和牙齿移动程度。采用秩和检验比较透明矫正器和固定矫正器牙槽骨缺损体积的差异,多元线性回归分析用于研究评估，和kappa统计用于评估内部一致性和重测信度。
结果：术后，大部分牙槽骨缺损发生在唇侧。明确矫正器组的骨开窗发生率为23.96%,固定矫正器组为26.18%,高于骨开裂的发生率(5.21%)。唇骨高度下降0.272mm,固定矫治器组中，前牙尖每向下侵入1毫米，腭骨高度增加0.617毫米。在清除对齐器组中，唇骨高度没有明显变化，冠状前牙每缩回1mm，腭骨高度减少0.447mm。
结论：在固定设备组中，前牙的侵入和缩回可能由于其在宫颈水平的压缩而导致牙槽骨吸收。本研究提供了一种基于CBCT的三维牙齿移动评价方法。
方法：这项回顾性临床研究包括32例患者。治疗前后收集锥形束计算机断层扫描（CBCT），以测量上颌前区的裂开和开窗的体积，前牙槽骨厚度、高度和牙齿移动程度。采用秩和检验比较透明矫正器和固定矫正器牙槽骨缺损体积的差异,多元线性回归分析用于研究评估，和kappa统计用于评估内部一致性和重测信度。
结果：术后，大部分牙槽骨缺损发生在唇侧。明确矫正器组的骨开窗发生率为23.96%,固定矫正器组为26.18%,高于骨开裂的发生率(5.21%)。唇骨高度下降0.272mm,固定矫治器组中，前牙尖每向下侵入1毫米，腭骨高度增加0.617毫米。在清除对齐器组中，唇骨高度没有明显变化，冠状前牙每缩回1mm，腭骨高度减少0.447mm。
结论：在固定设备组中，前牙的侵入和缩回可能由于其在宫颈水平的压缩而导致牙槽骨吸收。本研究提供了一种基于CBCT的三维牙齿移动评价方法。
