[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.