Objective: To measure and analyze the morphometric changes in the anterior alveolar bone during treatment and retention stage after retraction in bimaxillary adults using cone-beam CT(CBCT). Methods: Fifteen adult patients, four males and 11 females, aged 19 to 28 years[(22.2±3.1) years], who have completed orthodontic treatment and extracted four first premolar teeth for retraction in the Department of Orthodontics, The Affiliated Stomatological Hospital of Nanchang University from January 2016 to December 2018 were selected. CBCT was taken to assess the labial and palatal vertical bone level, total bone thickness at crest area, middle root area and apical area in pre-treatment (T1), post-treatment (T2) and at follow-up (maintained for more than two years) (T3). The differences in alveolar bone morphology at different stages were compared by single factor repeated measure ANOVA, and Pearson correlation analysis was performed on the amount of alveolar bone change in treatment stage and retention stage. Results: There were statistically significant differences in the alveolar bone height of the palatal side of maxillary anterior teeth, the labial side of maxillary lateral incisors and canine among three time points (P<0.05). The height difference of palatal alveolar bone of anterior teeth in T1-T2 stage was statistically significant (P<0.05). Palatal alveolar bone of upper and lower central incisors decreased by (1.52±0.32) and (4.96±0.46) mm, respectively. The height difference of anterior palatal alveolar bone was statistically significant in T2-T3 stage(P<0.05), the palatal alveolar bone height of central incisors increased by (1.20±0.27) and (3.14±0.35) mm respectively. The height difference of palatal alveolar bone in the anterior teeth of T1-T3 stage was statistically significant (P<0.05), and the height of palatal alveolar bone of central incisors was decreased (0.33±0.11) and (1.82±0.39) mm, respectively. There were statistically significant differences in the thickness of the cervical and middle root alveolar bone of anterior teeth among three time points (P<0.05). The difference of alveolar bone thickness of the cervical and middle root of anterior teeth at T1-T2 was statistically significant (P<0.05). decreased by (0.63±0.10) and (0.67±0.09) mm in lateral incisors, respectively. In the T2-T3 stage, the alveolar bone thickness of the crest area of the lower anterior teeth was significantly different (P<0.05), the alveolar bone thickness of mandibular central incisor crest area increased (0.09±0.03) mm. There were statistically significant differences in alveolar bone thickness in crest area and middle root of the incisors during T1-T3 stage (P<0.05), among which the middle root decreased by (0.38±0.16) mm and (0.63±0.13) mm, respectively. There was no statistically significant difference in other areas (P>0.05). The change of alveolar bone height in palatal side of upper anterior teeth at T2-T3 was very strongly negatively correlated with the change in T1-T2. The change of alveolar bone height in labial side of upper anterior teeth and lingual side of lower anterior teeth and the thickness of incisor root and neck were moderately strongly negatively correlated (r≤-0.8, P<0.001), the change of alveolar bone height in labial side of upper anterior teeth and lingual side of lower anterior teeth and the thickness of incisor crest area were moderately strongly negatively correlated (-0.8<r≤-0.4, P<0.05). Conclusions: For adult patients after retraction, anterior alveolar bone decreased significantly. In the retention stage, the same degree of bone apposition will occur, but still have alveolar bone loss compared with pre-treatment. The amount of alveolar bone change in the retention stage correlated with the amount of alveolar bone change in the treatment stage.
目的： 分析减数矫治的成年双颌前突患者矫治前后及保持阶段的前牙牙槽骨形态的变化，为临床安全内收前牙提供参考。 方法： 选取2016年1月至2018年12月于南昌大学附属口腔医院正畸科完成正畸治疗，并且减数4颗第一前磨牙强支抗内收前牙的成年患者15例，其中男性4例，女性11例，年龄（22.2±3.1）岁（19~28岁），对全部患者进行回访追踪，拍摄锥形束CT，分别于矫治前（T1期）、矫诊结束时（T2期）及随访时（保持期2年以上，T3期）测量患者上下前牙唇腭侧牙槽骨高度，以及根颈部、根中部、根尖部的牙槽骨厚度，通过单因素重复测量方差分析比较不同阶段牙槽骨形态的差异，对矫治前后（T1-T2）牙槽骨变化量、治疗结束至随访时（T2-T3）牙槽骨变化量进行Pearson相关性分析。 结果： T1、T2、T3期上前牙腭侧、上颌侧切牙及尖牙唇侧、下前牙唇舌侧牙槽骨高度总体差异均有统计学意义（P<0.05）。T1-T2期前牙腭侧牙槽骨高度变化量差异有统计学意义（P<0.05），其中上下中切牙腭侧牙槽骨高度分别降低（1.52±0.32）和（4.96±0.46）mm；T2-T3期，前牙腭侧牙槽骨高度变化量差异均有统计学意义（P<0.05），其中上下中切牙腭侧牙槽骨高度分别增加（1.20±0.27）和（3.14±0.35）mm；T1-T3期前牙腭侧牙槽骨高度差异均有统计学意义（P<0.05），其中上下中切牙腭侧牙槽骨高度分别降低（0.33±0.11）和（1.82±0.39）mm。上、下前牙根颈部及根中部牙槽骨厚度的3个时间点总体差异均有统计学意义（P<0.05）。T1-T2期前牙根颈部及根中部牙槽骨厚度差异均有统计学意义（P<0.05），其中上、下侧切牙根颈部的牙槽骨厚度分别减少（0.63±0.10）和（0.67±0.09）mm。T2-T3期，下前牙根颈部牙槽骨厚度差异均有统计学意义（P<0.05），下颌中切牙根颈部牙槽骨厚度增加（0.09±0.03）mm。T1-T3期上下切牙根颈部及根中部牙槽骨厚度差异均有统计学意义（P<0.05），其中根中部分别减少（0.38±0.16）和（0.63±0.13）mm，其他测量项目差异均无统计学意义（P>0.05）。T2-T3上前牙腭侧牙槽骨高度变化量与其在T1-T2变化量为极强负相关（r≤-0.8，P<0.001），T2-T3上前牙唇侧、下前牙舌侧牙槽骨高度变化量及切牙根颈部厚度变化量与其在T1-T2变化量呈中强负相关（-0.8<r≤-0.4，P<0.05）。 结论： 成年双颌前突患者减数矫治后，前牙区牙槽骨高度与厚度均明显减少。在保持阶段，会发生相应的骨增生，但牙槽骨较治疗前还是有所减少。保持阶段的牙槽骨变化量与矫治阶段牙槽骨变化量相关。.