Late Growth Period Orthopedic Therapy Versus Bimaxillary Surgery for Correction of Skeletal Class III

Abstract

To compare the effects of late orthopedic therapy with orthognathic surgery in skeletal class III cases. The subjects of the study were divided into 2 groups. Group 1 comprised 15 patients (8 females and 7 males) with a mean age of 14 years 6 months (range, 12 y 10 mo to 15 y 6 mo) and treated with maxillary expansion and a modified maxillary protraction appliance (MMPA). Group 2 comprised 11 patients (6 females and 5 males) treated with bimaxillary surgery (BMS) with a mean age of 23 years (range, 18 y 2 mo to 28 y 4 mo). Lateral cephalometric films were taken before (T1) and after orthopedic therapy (T2) in the MMPA group and before surgery (T1) and after fixed orthodontic therapy (T2) in the BMS group. Study groups were compared by analysis of variance and Tukey tests at the beginning and at the end of the treatment. Maxillary forward displacement (P < 0.01) and the increase in ANS-Me distance (P < 0.05) were higher in the BMS group than in the MMPA group. The mandible exhibited significant posterior rotation in MMPA group (P < 0.01). Mandibular effective length decreased in the BMS group and increased in the MMPA group. Soft tissue profile (G-Sn-Pg) improved in both groups (P < 0.05) and labiomental angle reduced in the BMS group, whereas an increase was observed in the MMPA group. Orthognatic surgery can be more effective in patients with increased mandibular length, more anteriorly positioned mandibles, and increased vertical dimensions.