Effect of Orthognathic Surgery on the Posterior Airway Space in Patients Affected by Skeletal Class III Malocclusion

Abstract

Introduction Dentofacial deformity refers to deviations from normal facial proportions and dental relationships that are severe enough to be handicapping. These anomalies involve many aspects of patient's life and are sometimes also associated with a reduction of pharyngeal air space. Through orthognathic surgery it is possible to treat dentofacial deformities: this kind of surgery has several effects on skeletal structures and it has changes, as it is demonstrated by many studies, also on the upper airways. The orthognathic surgeries commonly used to correct this deformity are the mandibular setback and the maxillary advancement procedures. This study aims to evaluate the effects of maxillary and mandibular surgery on pharyngeal airway dimensions in skeletal class III malocclusions. Materials and methods This study considers 76 patients, treated between 2007 and 2013 by maxillary advancement (11 patients), maxillary advancement and mandibular setback (39 patients), maxillary advancement, mandibular setback and genioplasty reduction (26 patients). Cranial latero-lateral radiography was used to compare oropharyngeal airway morphologies before and 1 year after surgery. Conclusion The surgeon should consider bimaxillary surgery rather than mandibular setback surgery to correct a class III deformity to prevent the development of obstructive sleep apnea syndrome; in fact, bimaxillary surgery might have less effect on reduction of the pharyngeal airway than mandibular setback surgery only.

Three-Dimensional Evaluation Of The Oropharyngeal Airway Changes After Bimaxillary Orthognathic Surgery Using Cone-Beam Computer Tomography: A Retrospective Analysis

“…Maxillary advancement, through Le-Fort I osteotomy, with an average 5.5 mm (range of 3-7 mm) was performed for both group in our study and this was in accordance Chang et al (17) Santagata et al (18) Gokce et al (19) who found that the maxillary advancement lead to anterior movement of the soft palate with subsequent increase in volume of the airway. Chang et al (17) found that maxillary advancement of 7 mm might be adequate to increase the volume of the airway especially nasopharyngeal airway, while more than7 mm maxillary advancement will cause a decrease in airway volume "Plateau effect".…”

“…Such new soft tissue relationships contribute to significant changes in the facial aesthetics and in the airway dimensions. (18)(19)(20)(21)(22)(23)(24) Accordingly, this retrospective study was designed to evaluate the volumetric, cross sectional surface area, and linear changes of the airway by using 3D cone beam computer tomography (CBCT) imaging after two different orthognathic surgeries in the Egyptian population.…”

The structural changes of upper airway and newly developed sleep breathing disorders after surgical treatment in class III malocclusion subjects

“…A strong correlation between the amount of mandibular setback and the decrease in the PAS was reported, and the low magnitude of mandibular posterior repositioning may explain the absence of significant changes in the PAS. [ 30 – 34 ] Our data showed that the posterior movement of the maxilla and the mandible narrowed the pharyngeal airway and reduction of pharyngeal airway might be related with the development of snoring or sleep apnea. The 7 subjects with postoperative snoring and OSA in our study may also have been influenced by a larger magnitude of maxillar or mandibular backward positioning.…”

Complications of Orthognathic Surgery

“…Bimaxillary orthognathic surgery for correction of Class III malocclusion caused an increase of the total airway volume and improvement of polysomnography parameters [59]. Bimaxillary surgery rather than mandibular setback surgery should be used to correct a class III deformity and reduce the risk of obstructive sleep apnea; in fact, bimaxillary surgery may have less effect on the pharyngeal airway patency than mandibular setback surgery alone [60]. A recent study suggested that BSSO presents less change in the pharyngeal airway space after mandibular setback surgery compared to intraoral vertical ramus osteotomy.…”