Objective To explore the relationship between the development of maxilla and dental arch and the size of denuded hard palate. Thus to get experimental proof for surgeons to choose a optimal surgical way for the treatment of cleft palate. Methods 48 three - week old SD male rats were divided into a control group and 3 experimental groups randomly. In the three experimental groups, different areas of bilateral palatal mucoperiosteum were excised respectively. Then the animals were injected with fluorescent labeling alternately by week. Biweekly, three animals in each group were sacrificed and the maxillae were dissected out and then measured the width of the maxilla and the dental arch, and investigated the difference of bone labelling. Results ①When the area was less than one quarter area of the palate, there was no obvious change of new bone formation, and better growth of maxilla and dental arch can be acquired. ②With the increasing area of denuded bone on the palate，the maxilla and dental arch retardation was more severe and palatal inclination of tooth was more obvious. ③The larger the area of bone denudation，the more negative influence to new bone forming and sutural structure，represented by more irregular bone labelling. As the denudation area was beyond three quarters of the hard palate，bone labelling was disperse and sutural structure lost. Conclusion There is affinity between the area of denuded bone on palate and the growth of maxilla and dental arch. The bigger the denudation area is， the more s evere the maxillary and dental arch constriction is.
