Angle Orthod. 2020 Mar;90(2):173-180. doi: 10.2319/041419-266.1. Epub 2019 Nov 26.
To evaluate changes in shape and alterations in thickness and vertical marginal bone levels of the alveolar bone around the maxillary and mandibular incisors before and after orthodontic treatment with premolar extraction using geometric morphometric analysis.
Thirty-six patients with Class I bialveolar protrusion who underwent orthodontic treatment with premolar extraction were included. Cone-beam computed tomographic scans were obtained from the patients before and after treatment. Five fixed landmarks and 70 semilandmarks were used to represent the morphology of the alveolar bone around the maxillary and mandibular incisors. The coordinates of the landmarks of the alveolar bones were generated by Procrustes fit. The labial and lingual alveolar bone thicknesses around the maxillary and mandibular incisors and vertical marginal bone level were assessed quantitatively.
There was a significant difference in shape change of the alveolar bone before and after treatment. The deformation grid of the thin plate spline showed that the thickness and vertical marginal bone decreased on the lingual side after treatment. Shape changes were greater for the lingual alveolar bone on the mandibular incisor than for the maxillary incisors.
Orthodontic treatment with premolar extraction might cause loss of alveolar bone around the maxillary and mandibular incisors. Careful consideration is needed to avoid iatrogenic degeneration of periodontal support around the incisors, particularly in the lingual area.
通过几何形态测量分析，评估上颌和下颌切牙周围牙槽骨在正畸治疗（拔牙）前后的形状变化以及厚度和垂直边缘骨水平的改变。
纳入 36 名接受拔牙正畸治疗的 I 类双前突患者。在治疗前后，对患者进行锥形束 CT 扫描。使用 5 个固定标志点和 70 个半标志点来表示上颌和下颌切牙周围牙槽骨的形态。通过 Procrustes 拟合生成牙槽骨标志点的坐标。评估上颌和下颌切牙周围唇侧和舌侧牙槽骨厚度以及垂直边缘骨水平。
牙槽骨治疗前后的形状变化有显著差异。薄板样条的变形网格显示，治疗后舌侧牙槽骨厚度和垂直边缘骨水平降低。下颌切牙的舌侧牙槽骨的形状变化大于上颌切牙。
拔牙正畸治疗可能会导致上颌和下颌切牙周围牙槽骨的丧失。需要谨慎考虑，避免切牙周围牙周支持组织的医源性退变，特别是在舌侧区域。
