Abstract: Objective: To investigate the changes in dental, skeletal, and soft tissue of maxillofacial region after 12 months of FRⅢ treatment, and to analyze the correlation between the movement of hard and soft tissues. Methods: Twenty-two patients with functional Class Ⅲ malocclusions were included in the observation group. Thirty-eight cases with similar occlusal and skeletal characters whose age matched with the observation group at the time of diagnosis were included in the control group A. Forty-two cases with similar occlusal and skeletal characters whose age matched with the observation group after 12 months of treatment were included in the control group B. The cephalograms of patients in the observation group were taken before and 12 months after treatment, the cephalograms of patients in the control group were taken when entering hospital. The changes in indexes of hard tissue, soft tissue, and correlation between sagittal soft and hard tissues were compared. Results: Compared with the control group A, all indexes in the observation group at the time of diagnosis were not significant different. Compared with the control group B, in the observation group after 12 months of treatment, the mandible length were shorter, posterior facial height were lower, ABN were wider, SNB were narrower, MP/SN and OP/SN were wider, the index of upper lip tension were higher, nasolabial angle were wider, chin angle were wider, Z angle were narrower, and the differences above were statistical significant different (P＜0.05). In the observation group, the changes of position of upper jaw bone and upper incisors were positively correlated with the changes of position of nose bottom point, upper lip protrusion point, lower lip protrusion point and soft tissue chin point (P＜0.05). The changes of position of lower incisors were positively correlated with the changes of position of soft tissue chin point (P＜0.05). Conclusion: FRⅢ appliance can restrain the growth of mandible, promote the mandibular rotation, increase the nasolabial angle, chin angle, and reduce Z angle. The changes of soft and hard tissues have certain correlation.

Key words: Malocclusion , FRⅢ appliance , Cephalometrics, Soft tissue , Hard tissue