Comparison of Pre-operative and Postoperative Skeletal and Dental Movements in Class III Patients Treated with Conventional and Surgery-first Techniques

Abstract

The conventional orthognathic-surgery technique involves lengthy pre-surgical orthodontic interventions, while invoking a surgery-first technique eliminates this necessity. Previous studies have reported the degree of skeletal and dental movements achieved using the conventional approach compared to orthodontic camouflage. However, none has directly compared the conventional orthognathic-surgery and surgery-first techniques. The objective of this study was to determine the magnitude of skeletal and dental changes achieved in class III patients with conventional orthognathic surgery (COS) and surgery-first (SF) techniques.In total, 82 lateral cephalograms for class III patients (n = 41) were analyzed for 2 groups: 1) COS (20.9±8.7 years) and 2) SF (20.7±6.6 years). Skeletal parameters such as SNA, SNB, ANB, Wits Analysis, Sn-GoGn, FMA, and lower anterior facial height and dental parameters such as U1-SN, U1-NA (°), U1-NA (mm), L1-NB (°), L1-NB (mm), and overjet were analyzed. Paired T-test analyses were performed to analyze the changes between pre-treatment and post-treatment parameters within the 2 groups, and 2-sample T-tests were used to compare the pre-treatment and post-treatment changes between the 2 groups.COS showed significant increase in L1-GoGn, overjet, ANB, SNA, and Wits analysis. SF showed significant increase in L1-GoGn, L1-NB (°), L1-NB (mm), overjet, ANB, SNA, and Wits analysis and significant decrease in U1-NA (°) and U1-NA (mm). The comparison between COS and SF showed that there was no statistically significant difference in the skeletal and dental parameters between the 2 groups.The results indicate that orthognathic surgery in class III patients with conventional orthognathic-surgery and surgery-first techniques does not produce a difference in results among the skeletal and dental parameters, suggesting that either technique can be used to achieve similar results with a comparable degree of skeletal and dental movement in patients with class III malocclusion.