A Comparative Study On Surgical And Non-surgical Orthodontic Treatment Of Skeletal Class â…¢ Malocclusion

Objective: The outcome of skeletal class III malocclusion after surgical and non-surgical treatment was compared to provide guidance for clinic treatment.Methods: 22 patients with skeletal class III malocclusion after successful orhtodontic or orthognathic treatment were collected. Non-surgical group consisted of 11 patients(5 male and 6 female, with average age of 13.3 years'old ) treated with edgewise appliance(straight wire appliance). Surgical group consisted of 11 patients(6 male and 5 female, with average age of 22.6 years'old ) treated with conbined orthodontic and orthognathic surgery. Lateral cephalometric radiographs before and after treatment of each patients were analized. Paired t-test was performed to evaluate the significance of change after treatment in both groups. Radomized block design t-test was performed to evaluate the difference between two groups before and after treatment.Results:In non-surgical group, ANB angle attained significant increase(P<0.05), but ANB angle was still negative value and class I facial form was not achieved. L1-MP angle was discreased 6.62°on average (P<0.05) and nomal anterior overjet and overbite was attained through lingual inclination of lower incisors. Ls-Sn-SN and Sn-N'-Si angles were discreased (P<0.05). Distance of Li to E line was discreased 1.85mm and soft tissue profile was improved dramatically. Before treatment, there was no significant difference in cephalometric variables indicating class III deformity severity between surgical and non-surgical groups.In surgical group, ANB angle was obviously increased(P<0.05) and class I facial form was attained with normal anterior overjet and overbite. N'-Sn-Pos angle was increased 7.60°(P<0.05), while S-N'-Si and S-N'-Pos angle were discreased(P<0.05). Soft tissue profile was improved dramatically.After treatment, there was significant difference in ANB angle and Wits value between surgical and non-surgical groups(P<0.05). In surgical group, labial inclination of lower anterior teeth was much higher and L1-NB angle and L1-NB distance was of significant difference compared with non-surgical group . After treatment, there was no significant difference in soft tissue profile between two groups. Conclusion:Skeletal class III malocclusion with permanent dentition could be successfully treated with straight wire appliance technique and soft tissue profile could be improved. Skeletal deformity was corrected to certain degree.Skeletal III malocclusion treated with orthodontic and orthognathic surgery could achieved class I skeletal pattern and soft tissue profile could be dramatically improved. Treatment effect of orthognathic surgery on skeletal deformity was obviously better than non-surgical treatment.Orthodontic and orthognathic surgery can achief better intermaxillary relationship improvement than straight wire appliance technique in Skeletal class III malocclusion with similar skeletal deformity , but there was no significant difference in soft tissue improvement...