OBJECTIVETo observe the whole process of cranio-maxillofacial development of an animal model with bilateral premaxillary clefts, after being exerted with premaxillary retro-pressing forces.

METHODSExperimental rabbits with premaxillary clefts and without clefts were exerted with retro-pressing forces respectively. Roentgenographic cephalometric analysis and different investigations of premaxillary suture were performed during the whole craniofacial development.

RESULTSThe longitudinal cephalometric analysis showed that a temporary retarding effect of mid-facial growth existed. The hindrance of maxillary growth potentiality did not occur in spite of being exerted retro-pressing force as to this experimental extent.

CONCLUSIONS(1) Infant rabbit combined with the designed retro-pressing appliance is an ideal experimental model for quantitative study of active orthopedic treatment of protruding premaxilla. (2) Using active preoperative orthopedics to reposit the protruding premaxilla of bilateral cleft palate is a reasonable and effective approach.