| OBJECTIVES: To investigate the influence of class III orthopedic forces in the craniofacial sutures and to elucidate the mechanism of class III malocclusion treatment.SUBJECTS AND METHODS:6 healthy male Rhesus monkeys, which had mixed dentition were employed in this study. These monkeys were divided into 3 groups,4 monkeys were used as one and a half months and three months experimental groups,2 monkeys served as control. Each of the experimental monkeys were fitted with casted Twin-block Magnetic Appliance HI (TMA-III),For evaluating the effects of protraction of dentofacial complex, oral pictures ,model casts and lateral cephlograms of each animal were taken at the beginning .during and at the end of experiment. Before taking the cephalograms, mental paired implants of silver amalgam were placed across the zygmaticomaxilary suture, zygmaticotemprol suture and zygmaticofrontal suture in each animal. To determine the time and extent of skeletal change occurred ,each animal was given vital staining before and during the experimental period.RESULTS: Through observation of maxillary position and cephalometric analysis,the maxilla was displaced anteriorly whereas the mandible rotated posteriorly ;the maxilla incisors moved in the anterior direction whereas the mandibular incisors moved posteriorly. Craniofacial sutures were activated by class III orthopedic forces in histological observation. The distance between the paired implants across sutures were enlarged significantly in experimental groups. The bony deposition of the sutures were distinctly found during the experimental period. Butforces can activated the bony deposition and were safe during treatment. Significant changes differing from physiological growth remodeling were observed in the craniofacial sutures under class III orthopedic forces. No destructive changes were found during the experiment. So we can conclude that proper class III orthopedic forces are safe and effective.
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