上颌快速扩大兔腭中缝组织改建的连续组织学研究

目的研究上颌快速扩大腭中缝牵张成骨的连续过程及规律，了解快速扩张腭中缝的缝组织反应和组织再生机理。方法选用处于生长期新西兰大白兔52只，随机分为13组，实验组5组、对照组6组，荧光标记的实验组和对照组各1组。采用螺旋分裂基托扩大矫治器（Haas矫正器）扩张兔上牙弓，快速扩张期2周，固定期4周。扩张速率为0．25mm／12h，共扩张牵引14天，分别于即刻、第7、14、21、28、42天取材，标本常规进行组织学观察。并利用激光共聚焦扫描显微镜及荧光标记观察快速扩张腭中缝成骨活动的情况。结果快速扩张2周后可见腭中缝明显增宽，可见创伤性反应，成骨和成纤维细胞大量增殖，大量胶原纤维沿扩张力方向有序排列，成骨活动沿骨缝边缘平行沉积。快速扩张的腭中缝有强烈的血管生成反应，新生骨组织改建活跃，直至新的骨缘形成。缝恢复正常的形态。荧光标记观察实验组骨沉积带明显宽于对照组。结论扩张的腭中缝新骨改建主要发生在腭中缝骨缘。腭中缝改建的过程是纤维修复和骨组织再生过程。

A serial histological study on tissue response to rapid maxillary expansion in the midpalatal suture

Objective To study the continuous process of tissue response and regularity of osteogenesis of midpalatal suture expansion. Methods For the chronic experiment, a total of 52 male,8 - week- old New Zealand White rabbits were randomly allocated into 13 groups. Five groups were experimental groups, 6 groups were control groups. In addition , fluorescence labeling groups consisted of a experimental group and a control group. A Haas appliance was used for rapid expansion of the midpalatal suture at a rate of 0.25mm/12h for 14 days. Four animals of experimental group and 4 animals of control groups were sacrificed on 0d, 7d, 14d, 21d,28d, 42d after the start of activation respectively. Eight animals of fluorescence labeling groups were killed on 42d. Sutural tissue changes were examined histologically. Laser scanning confocal microscopy and fluorescence labeling in bone were used to observe newly mineralized bone. Results Rapid maxillary expansion induced more significantly midpalatal sutural widths of experimental group than that of sham control on 7d, 14d. Then a great amount of osteoblasts and fibroblasts proliferated, new bone deposited along the bone front. Intramembranons bone formation and remodeling were found in the expanded suture. Fluorescent labeling of newly formed sutural bone demonstrated more osteogene.sis on a experimental group in comparison with a control group. Conclusion The new bones formation belongs to intramembranous osteogenesis. The midpalatal sutural expansion is a process of bone tissue regeneration and fibrous tissue repair.