目的: 使用锥形束CT (cone-beam computed tomography,CBCT)影像研究上颌反复快速扩缩前方牵引后上颌及周围骨缝的三维变化,探讨该变化与颧颌缝成熟度之间的关系,分析上颌前移的影响因素,为骨性Ⅲ类错牙合畸形的早期治疗提供参考。方法: 选择36例上颌后缩患者,使用随机化区组设计分为单次扩弓组和反复扩缩组(临床试验注册号:ChiCTR2000034909), 患者7~13岁,安氏Ⅲ类错牙合,前牙反牙合,头影测量显示ANB角<0°,Wits值<-2 mm,上齿槽座点(A点)至过鼻根点(N点)的眼耳平面垂线的距离(A-Np)<0 mm。单次扩弓组行上颌单次快速扩弓后面罩前方牵引,反复扩缩组行上颌反复快速扩缩后面罩前方牵引。使用Dolphin 11.7软件对每组治疗前后的CBCT影像进行头位校正,使用Mimics 10.01软件进行三维重建,测量上颌骨及其周围骨缝标志点,使用独立样本t检验、双因素方差分析、Pearson相关性分析和回归分析进行统计学分析。结果: 除2例患者未完成复诊随访外,其余34例患者均完成治疗。与单次扩弓组相比,反复扩缩组患者治疗后上颌及周围骨缝标志点矢状前移量更大,颧颞缝、颧颌缝及颧额缝标志点矢状向分别前移1.21 mm、2.20 mm及1.43 mm,组间差异均有统计学意义(P<0.05)。除颧颞缝外,其余骨缝标志点矢状向前移量不受颧颌缝成熟度影响(P>0.05)。反复扩缩组治疗后,颧颌缝标志点和A点矢状向前移量之间相关性较强(P<0.01),回归分析R²=42.5%。结论: 与上颌单次快速扩弓相比,上颌反复快速扩缩前方牵引对于早期治疗上颌后缩可能效果更佳;上颌反复快速扩缩前方牵引后,颧颌缝作为上颌矫形力作用的主要骨缝之一,其矢状向前移量与上齿槽座点的前移量相关性较强。

Objective: To assess three-dimensional (3D) changes of circummaxillary sutures following maxillary protraction with alternate rapid palatal expansions and constrictions (RPE/C) facemask protocol in maxillary retrusive children, and to investigate the relationship between the changes of circum-maxillary sutures and zygomaticomaxillary suture (ZMS) maturation, and to explore the factors of maxilla forward movement with RPE/C and facemask. Methods: In the study (clinical trial registration No: ChiCTR2000034909), 36 maxillary retrusive patients were recruited and block randomized to either the rapid palatal expansion (RPE) group or the RPE/C group. Patients aged 7 to 13 years, Class Ⅲ malocclusion, anterior crossbite, ANB less than 0°, Wits appraisal less than -2 mm, and A-Np less than 0 mm were included in the study. The RPE group received rapid palatal expansion, whereas the RPE/C group received alternate rapid palatal expansions and constrictions, and both with facemask protraction. Head orientations of cone-beam computed tomography (CBCT) images were implemented by Dolphin 11.7. 3D measurements of circummaxillary sutures on CBCT images were evaluated using Mimics 10.01 before (T0) and after treatment (T1). The changes were analyzed with independent t test, two-way ANOVA, Pearson correlation and regression analysis. Results: Two subjects in the RPE/C group were lost to follow-up. A total of 34 patients reached the completion criteria and were analyzed. Compared with the RPE group, sagittal changes of circummaxillary sutures were significantly increased in the RPE/C group with 1.21 mm advancement of zygomaticotemporal suture, 2.20 mm of ZMS, 1.43 mm of zygoma-ticofrontal suture (P<0.05, respectively). Except for the zygomaticotemporal suture, the rest forward sagittal changes of other circummaxillary sutures showed no major difference in terms of the ZMS maturation. The Spearman’s correlation in RPE/C indicated a strong positive correlation of sagittal changes between ZMS and point A (P<0.01) with a regression analysis R ²=42.5%. Conclusion: RPE/C might be more effective on the treatment of maxillary retrusive children. As one of the major mechanical loading sutures during orthopedic therapy, ZMS showed a strong positive correlation with point A on sagittal changes.