The Effects of Multidisciplinary Treatment in a Skeletal Class III Patient on Posterior Airway Space and Respiratory Function

Objective: To evaluate the cephalometric, oropharyngeal airway volume, respiratory function during sleep and pulmonary functions changes in a severe Class-III patient undergoing bimaxillary orthognatic surgery. Method: A 19-year-old male patient referred for treatment with complaint inability to incise food and unaesthetic profile. Cephalometric evaluation revealed a significant Class-III skeletal discrepancy (ANB= -15º) with a negative overjet of 12mm. Computed tomography (CT) (Aquilion 64, Toshiba Medical Systems, Otawara, Japan) scans were obtained to determine the surgery and a stereolithographic model (SLA) was created preoperatively using SimPlant (Materialise, Belgium) software. According to the SLA planning, maxilla was advanced 10mm with LeFort-I downfracture, mandible was positioned back 13mm with BSSO. Cephalometric analyses, pulmonary function tests (PFT), and a 1-night sleep study for full polysomnography (PSG) were performed before and repeated after 6 months to surgery. Results: Maxillary advancement and mandibular setback revealed an occlusion with a Class I molar and canine relationship. The overbite and overjet relationships were ideal and facial esthetic appearance was improved as a result of the reduction in the lower third of the face height in accordance with cephalometry. The PSG, PFT and cephalometric alterations indicated an enlargement in oropharyngeal volume, better airflow and improved sleep quality. Conclusion: A large amount of mandibular setback might inhibit biological adaption and ca usesleep-disordered breathing. Therefore, it might be better to consider mandibular set back with maxillary advance that does not reduce the airway for patients with skeletal Class-III malocclusions. The patient gained an appropriate facial aesthetics and oral function using multidisciplinary approach.