[Stability of orthodontic treatment in the patients with cleft lip and palate].

Severe maxillary deficiency is often seen in cleft lip and palate patients due to multiple factors such as congenital defect, traumatic effect of surgeries and constriction of scar tissue, which causes moderate to severe crowding and anterior and posterior crossbite. Orthodontic treatment is usually difficult and time consuming. Upper arch expansion and maxillary protraction are often carried out to release transverse and sagittal intermaxillary discrepancy. Orthodontic treatment for cleft patients is different from that of non-cleft patients. Special management is needed and the stability of treatment should be considered. Relapse usually occurred after upper arch expansion especially in canine and premolar area. Over expansion should be cautious and orthognathic surgery may reduce the unstability of expansion. Maxillary protraction can improve the facial esthetics of the children with cleft. Alveolar bone grafting could improve the protraction effect and reduce the side effect such as clockwise mandibular rotation and upper incisor proclination. Forward movement of maxilla by protration is stable and continuous growth of the mandible is the most liable factor causing relapse. High mandibular angle and over growth of mandible are the risk factors of unstability of maxillary protraction.由于先天性颌骨缺陷、多次手术创伤及手术瘢痕挛缩等原因，唇腭裂常并发严重的上颌发育不足，进而导致严重的牙列拥挤、前牙及后牙反■。唇腭裂的正畸治疗过程复杂、矫治难度大、时间跨度长。解决上颌宽度不足的上颌扩弓以及针对上颌发育不足的前方牵引是唇腭裂治疗的常用方法。但唇腭裂的特殊性使其正畸治疗与非唇腭裂患者存在显著差别，常需特殊处理。唇腭裂正畸疗效的稳定性同样值得关注。唇腭裂上颌扩弓后存在复发倾向，尖牙及前磨牙区复发明显。矫治时应避免过度扩弓，必要时联合正颌手术，以减小扩弓的不稳定性。儿童期行前方牵引治疗可有效改善患者面型；牙槽突植骨可提高前方牵引效果，减小下颌顺时针旋转量以及上切牙唇倾等不利变化。患者生长发育基本完成时，上颌前方牵引的效果可基本维持，但下颌的继续生长是前牙反■复发的最大威胁。对于下颌平面角高角及下颌发育过度的患者，前方牵引疗效的稳定性较差。.