Aim: Class Ill skeletal deformity may be the result of mandibular prognathism and/or maxillary deficiency. In adult patients , orthognathic surgery is used for treatment. Historically, the surgical correction of class III deformities was achieved just by mandibular setback, but nowadays other methods of surgery are used. Orthosurgery treatments, in addition to improvement in masticatory function, occlusion and esthetics, may lead to changes in upper airway dimensions, position of hyoid, tongue and soft palate. The purpose of this study was to evaluate cephalometric changes in upper airway dimensions of skeletal class III patients following orthodontic treatment and bimaxillary surgery.
Material and methods: In this retrospective study, pre-treatment and post-treatment (6-12 months after surgery) lateral cephalograms of skeletal class III patients were used for analysis. All of the patients of a private office in Hamadan who had the inclusion criteria were selected. Cephalograms were traced manually. All the measurements were done with ruler.Then paired t test was used for analysing the data.
Results: Changes in upper airway linear measurements, position of hyoid, base of tongue, soft palate size and angle. and craniocervical angle, were not statistically significant (p>0.05). But there was a significant increase in nasopharynx and oropharynx surface area (p<0.05).
Conclusion: Orthodontic treatment with bimaxillay surgery in surgical class III cases can increase surface area of oropharynx and nasopharynx, and it seems that there is no risk factor for breathing disorders.