OBJECTIVETo investigate the influence of class III forces in craniofacial morphology and sutural histology in Rhesus monkeys.

METHODSSix male Rhesus monkeys in mixed dentition were employed in this study, two as 90-day experimental group, two as 45-day experimental group and the other two as control respectively. The experimental monkeys were casted magnetic orthopedic appliance-III (MOA-III), the control monkeys received no treatment. Intraoral photographs, casts and cephalometric radiographs of each animal were obtained at the beginning and at the end of the experiment. Fluorescent and haematoxylin-eosin staining were used to observe the histological changes in craniofacial sutures. RESULTS; In experimental groups, the maxillomandibular relationship changed more significantly in 90-day experimental group than 45-day experimental animals. But changes were scarcely noted in the control. The bony depositions of the sutures were distinctly found during the experimental period, especially in zygomaticomaxillary, transverse palatine, pterygopalatine and zygomaticotemporal sutures.

CONCLUSIONThis study indicates that this kind of magnetic appliance could cause skeletal and dental changes of maxilla and mandible, and change the arrangement of connective tissues in craniofacial sutures, and lead to significant new bone deposition in craniofacial sutures.