State Key Laboratory of Oral Diseases and Department of Orthodontics, West China Hospital of Stomatology, Sichuan University, Chengdu, China; Nanjing Stomatological Hospital, Medical School of Nanjing University, Nanjing, China.
State Key Laboratory of Oral Diseases and Department of Orthodontics, West China Hospital of Stomatology, Sichuan University, Chengdu, China.
Am J Orthod Dentofacial Orthop. 2020 Jun;157(6):783-791. doi: 10.1016/j.ajodo.2019.06.017.
Rapid palatal expansion is an effective intervention for correcting transverse maxillary deficiency in growing patients. However, relapse after treatment is often observed, and the mechanisms of tissue remodeling during expansion and relapse remain unclear. This study aimed to gain insight into such a mechanism.
A total of 24 5-week-old male Wistar rats were randomly divided into either the expansion or sham device (control) group. Each rat underwent 7 days of expansion and 7 days of relapse. The width of the dental arch, palatal bone, and suture, as well as the angle of the teeth, were measured. Tissue remodeling in the midpalatal suture was examined using microcomputed tomography and histologic and immunohistochemical analyses.
The mechanical expansion force caused an increase in arch width, which relapsed after the removal of force. Bilateral tilting of the teeth and midpalatal suture expansion contributed to the widening of the maxillary arch, and only the relapse of the palatal bone width was observed. Histochemical staining showed that suture tissue remodeling was activated by mechanical force in the expansion group and reverted to the level of the control group after relapse. Immunohistochemistry staining revealed that the expression of cathepsin K, osteocalcin, and collagen type I was higher in the expansion group than that in the control group on day 7; however, the difference dissipated by day 14.
The expansion force stimulated osteogenic activity in the midpalatal suture area. After removal of the expansion force, tissue remodeling went back to the normal level.
快速腭扩张是一种有效的干预措施，可用于矫正生长患者的横向上颌骨不足。然而，治疗后经常观察到复发，扩张和复发过程中的组织重塑机制仍不清楚。本研究旨在深入了解这种机制。
总共 24 只 5 周龄雄性 Wistar 大鼠被随机分为扩张组或假手术（对照）组。每组大鼠均经历 7 天的扩张和 7 天的复发。测量牙弓、腭骨和缝的宽度以及牙齿的角度。使用微计算机断层扫描和组织学及免疫组织化学分析检查中缝组织重塑。
机械扩张力导致牙弓宽度增加，在去除力后复发。牙齿的双侧倾斜和中缝扩张有助于上颌弓的增宽，仅观察到腭骨宽度的复发。组织化学染色显示，扩张组的缝组织重塑被机械力激活，在复发后恢复到对照组的水平。免疫组织化学染色显示，在第 7 天，扩张组的组织蛋白酶 K、骨钙素和胶原 I 的表达高于对照组；然而，第 14 天差异消失。
扩张力刺激中缝区域的成骨活性。在去除扩张力后，组织重塑恢复到正常水平。
