上颌四眼圈簧扩弓后对上颌牙齿及上颌骨变化影响的 CBCT 研究

目的：使用锥体束 CT（CBCT）评估上颌四眼簧慢速扩弓后上颌牙齿及上颌骨宽度的变化。方法：选择13例需要综合性正畸治疗的患者（男5例，女8例），平均年龄（14．4±2．2）岁，使用上颌四眼圈簧扩弓。对患者扩弓前（T1）后（T2）的变化进行 CBCT 扫描，测量扩弓前后两侧尖牙、第一前磨牙、第二前磨牙和第一磨牙之间的牙冠和根尖之间的宽度，第一磨牙的倾斜度，基骨弓和腭中缝宽度的变化。应用 SPSS 17．0软件对测量结果进行配对 t 检验。结果：四眼圈簧扩弓后牙弓变化明显。4对牙的牙间距分别增加了（2．47±1．05）mm、（2．97±1．90）mm、（2．79±1．21）mm、（3．15±1．15）mm，根尖距分别减小了（1．19±0．40）mm、（2．12±0．68）mm、（2．02±0．65）mm、（1．34±0．63）mm，左侧磨牙倾斜度减小了4．45°±2．86°，右侧磨牙倾斜度减小了4．02°±1．45°，基骨弓宽度增加了（2．37±0．96）mm，腭中缝宽度增加了（1．21±0．50）mm，差异均具有统计学意义（P ＜0．001）。结论：四眼圈簧扩弓器对上颌牙弓的扩弓主要通过牙齿倾斜移动完成，而非整体移动。

Changes of maxillary teeth and maxilla following quad helix maxillary expansion observed by Cone-Beam CT (CBCT)

Objective:To evaluate dental and skeletal changes following slow maxillary expansion with quad helix using Cone-Beam computer tomography (CBCT).Methods:13 patients(5males and 8 females,mean age 14.38 ±2.22 years)requiring maxillary ex-pansion as a part of their comprehensive orthodontic treatment were included.Each patient had CBCT images taken pre-(T1 )and post-(T2)maxillary expansion with quad helix.Changes of the distances between bilateral canines,first premolars,second premo-lars,first molars,the width of basal bone and palatal suture were measured.paired t-test results were analyzed using SPSS 17.0 soft-ware.Results:The distances between the 4 bilateral teeth increased by (2.47 ±1.05)mm,(2.97 ±1.90)mm,(2.79 ±1.21) mm and (3.15 ±1.15)mm,the apical distances decreased by (1.19 ±0.40)mm,(2.12 ±0.68)mm,(2.02 ±0.65)mm and (1.34 ±0.63)mm,respectively.The inclination of the first molars were decreased by (4.45 ±2.86)°and (4.02 ±1.45)°on the left and right side respectively.The width of basal bone and palatal suture increased by (2.37 ±0.96)mm and (1.21 ±0.50)mm respectively,the differences between T1 and T2 were all statistically different(P <0.001).Conclusion:Quad helix expands maxil-lary arch by greater dental changes than by skeletal changes.