| Objective:1.To evaluate the skeletal stability of one patient with skeletal class III malocclusion after orthodontic surgery.2.To explore the physiological changes of the upper airway in one patient with skeletal class III malocclusion after orthodontic surgery.3.To explore the position changes of condyle in one patient with skeletal class III malocclusion after orthodontic surgery.Methods:This study included 1 patients who had skeletal class III malocclusion and were treated with bimaxillary orthognathic surgery(Le Fort I&BSSRO&genioplasty)and at Shandong University,School of Stomatology,Department of Orthodontics.The patient was treated with straight wire arch correction technique.Preoperative orthodontics:align the upper and lower teeth,coordinate the upper and lower arch width and eliminate the occlusal interference.Bimaxillary orthognathic surgery.Postoperative orthodontics:adjust the occlusion locally.The patient underwent CBCT examinations and filled the questionnaires at initial visit(TO),3 months after surgery(T1),1 year after surgery(T2),2 year after surgery(T3)and 3 year after surgery(T4).The patient was in upright position with a natural head position(NHP)and she was instructed to maintain light contact between the molars in natural occlusion,to keep quiet breathing and to avoid swallowing and other movements during the scanning period.The CBCT data were converted into DICOM(Digital imaging and communication in medicine)format,and 3D images of the craniofacial and pharyngeal airway morphology were reconstructed with a Dolphin Imaging software(Dolphin Imaging,Version 11.8,Chatsworth,CA,USA).For the measurement of surgical skeletal changes and hyoid positions,4 points and 2 reference plane were used on MSP.The volumes and minimum cross-sectional area of each PAS segments were measured.The craniocervical angle and cervical inclination were also measured on MSP.To evaluate changes in the condylar axis,the angular measurements on three planes were obtained according to the reference planes.The spaces between the condyle and glenoid fossa were used on the sagittal multiplanar reconstruction image.Results:1.The maxilla moved forward 1.4mm,the front of which moved downward 1.6mm,and the mandible moved backward 4.6mm.In the first year after surgery,the position of maxilla was basically stable while the mandible moved forward 0.8mm and then it became stable 2 and 3 years later.The hyoid mainly showed a backward and downward movement,and it tended to move back in the first year after surgery,but it still did not return to its original position.2.After surgery,the retropharynx and lingual pharynx significantly narrowed,and they continued narrowing within 1 year.2 and 3 years after surgery,the upper airway significantly widened.3.There was no significant change in head posture within 1 year after surgery while the head posture significantly extended 2 and 3 years after surgery.4.The sagittal axial angle of the left and right condyles increased significantly after orthodontic surgery,which decreased in the first year after surgery.The coronal axial angle of the left condyle decreased after surgery,and there was no significant change in 1~3 years after surgery.5.The patient did not develop OSAHS symptoms during the whole period.Conclusion:1.Although the amount of mandibular setback was limited,we still found that the upper airway narrowed to a certain extent,which was supposed to stimulate the strong physiological compensation mechanism of the patient,and the extension of the head position in order to open the airway;2.In BSSRO,the proximal segment of the mandibular was clockwise along the axis of the inner and outer pole of the condyle.After the surgery,due to the unstable occlusal,the bone tended to return to the original position and the mandible moved forward a little.3.Postoperative adjustment established the centric and dynamic occlusal balance,which is conducive to the stability of the oral-facial nerve and temporomandibular joint,and thus to the skeletal stability. |
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