Orthognathic surgery has been used regularly to treat dentofacial deformities. The surgical procedures affect both the facial appearance as well as the posterior airway space (PAS). Our current literature indicates that setback procedures produce an inferior repositioning of the hyoid bone and posterior displacement of the tongue and the soft palate. These movements cause anteroposterior and lateral narrowing of the PAS. Most authors agree that these effects are permanent. The PAS changes in turn produce an adaptive posturing, with an increased craniocervical angle to open up the PAS. Even though most patients do not display snoring and obstructive sleep apnoea (OSA) post-surgery, there is certainly an increased possibility in patients with already compromised airways. Therefore, patients who are undergoing orthognathic surgery should be screened for excessive daytime somnolence, snoring, increased body mass index (BMI) and medical conditions related to OSA and sent for an overnight polysomnography (PSG) if OSA is suspected. Then the proposed treatment plan may be modified according to the risk of potential airway compromise or even to improve it. Conversely, advancement of the maxilla and mandible causes widening of the airway in both the anteroposterior and lateral dimensions. This effect would translate to better airflow and decreased airway resistance. This is supported by the evidence showing high success rates when orthognathic surgery, especially maxillomandibular advancement (MMA), is utilised to treat OSA.
Airway Obstruction ; etiology ; surgery ; Cephalometry ; Humans ; Malocclusion ; complications ; pathology ; surgery ; Malocclusion, Angle Class II ; surgery ; Malocclusion, Angle Class III ; surgery ; Mandibular Advancement ; Oral Surgical Procedures ; Osteotomy ; Treatment Outcome

PURPOSE: The purpose of this study was to measure the anteroinferior changes and the degree of vertical changes to facilitate the prediction of treatment outcome in patients undergoing genioplasty only, genioplasty with bilateral sagittal split ramus osteotomy (BSSRO), genioplasty, or BSSRO and Lefort I osteotomy. MATERIALS AND METHODS: Serial cephalometry was performed on 25 patients at 1-year follow-up after genioplasty, to assess skeletal changes and relapse. Surgery was performed using conventional techniques. RESULTS: The mean ratio was 0.9 : 1 of soft tissue to skeletal movement at pogonion, but the average difference between hard and soft tissue was large; thus, the prediction of anteroposterior soft tissue changes was quite inaccurate. CONCLUSION: We observed a good correlation between the amount of hard versus soft tissue change with surgery in the horizontal direction, but a poor correlation in the vertical plane.
Adolescent ; Adult ; Female ; Humans ; Male ; Malocclusion, Angle Class III/pathology/*surgery ; Mandible/pathology/*surgery ; Osteotomy/methods ; Osteotomy, Le Fort/methods ; Reconstructive Surgical Procedures/*methods ; Treatment Outcome ; Young Adult

OBJECTIVETo Investigate the changes in dentition at each treatment stage and to get some guidelines for clinical work.

METHODSThirty-one cephalometric films of skeletal class III malocclusion patients were analyzed. All the patients were treated by orthodontic and orthognathic surgery.

RESULTSDuring presurgical orthodontic treatment, the lower Incisors were decompensated (labially Proclined by 7 degrees ). The upper incisors were uprighted during surgery following rotation of maxilla. After surgery, the upper anterior teeth kept tipping for ward. While the lower anterior teeth were In stable. The dentition was in good occlusion during observing stage.

CONCLUSIONSLingually tipped lower Incisors were decompensated after presurgical orthodontic treatment in class III malocclusion patients, and lower Incisors kept in stable during observing stage, while the upper incisor had a little bit relapse.

Adolescent ; Adult ; Dentition ; Female ; Humans ; Male ; Malocclusion, Angle Class III ; pathology ; surgery ; Odontometry ; methods ; Orthodontics, Corrective ; methods ; Time Factors ; Treatment Outcome

Based on the anatomic structure of a girl with class III skelet al malocclusion, a three-dimensional finite element biomechanical model of facial soft tissue was established. With the use of this model, three surgery plans of distraction osteogenesis, LeFort I, II, III maxillary complex advancement in the direction of functional occlusal plane, were simulated. As a result, the facial soft tissue deformation was predicted and the ratio of the facial location deformation to the free bone advancement was calculated. The facial shape after surgery could be viewed in 3D. In addition, the location of center of resistance was investigated when the free bone was protracted forward in the process of LeFort I maxillary complex advancement; it was located at a site about 30 mm posterior to the soft tissue A point. The research result indicates that three-dimensional finite element research on distraction osteogenesis can provide instruction for setting the suitable protraction point and direction of the protraction force in surgery, and by predicting the facial soft tissue deformation, it also can provide the surgeon and patient with information on the options and reference to the surgery plans.
Adolescent ; Cephalometry ; Computer Simulation ; Face ; diagnostic imaging ; pathology ; surgery ; Female ; Finite Element Analysis ; Humans ; Imaging, Three-Dimensional ; Malocclusion, Angle Class III ; diagnostic imaging ; pathology ; surgery ; Maxilla ; diagnostic imaging ; pathology ; surgery ; Models, Biological ; Osteogenesis, Distraction ; instrumentation ; Osteotomy ; Radiography