[Application of PAR index and cephalometrics for camouflage therapy and orthodontic-orthognathic surgery in adults with skeletal Class Ⅲ malocclusion].

PURPOSE: To investigate the value of PAR index combined with cephalometry in evaluating the efficacy of mild to moderate skeletal Class Ⅲ malocclusion. METHODS: Sixty-five adult patients with skeletal Class Ⅲ malocclusion were selected and divided into group C (camouflage therapy) and group S (orthodontic-orthognathic surgery)according to different treatment methods. PAR index and cephalometric values before and after treatment in each group were compared, and then the differences of PAR index and cephalometric values before and after treatment between the two groups were compared. The clinical effect was evaluated by these indexes. SPSS 25.0 software package was used for data analysis. RESULTS: In PAR index, the tooth alignment, occlusion, overjet, overbite, midline, total score and weighted total score after treatment of both groups were all significantly lower than those before treatment(P＜0.001). The differences of left and right buccal bite and total posterior bite of group S before and after treatment was significantly larger than those of group C(P＜0.001). In cephalometric measurement, the differences of SNA, NA-PA, L1-NB, U1-L1, U1-SN and L1-MP in group C before and after treatment were significantly different(P＜0.05), while those in group S before and after treatment were SNA, SNB, ANB, NP-FH, NA-PA, L1-NB, U1-L1U1-SN and L1-MP(P＜0.001). The differences of SNB, ANB and NP-FH before and after treatment in group S were significantly greater than those in group C(P＜0.001). CONCLUSIONS: Both treatments are effective for adult patients with mild to moderate skeletal Class Ⅲ malocclusion. The effect of orthodontic-orthognathic treatment is better than camouflage therapy in occlusal relationship of posterior teeth, the position of mandible relative to cranium, the mutual position of upper jaw and lower jaw relative to cranium, and the degree of mandibular convexity. PAR index combined with cephalometric measurement can effectively judge the clinical effect of adult patients with mild to moderate skeletal Class Ⅲ malocclusion, which is a good evaluation method.