• Maxillofacial Plastic and Reconstructive Surgery
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• v.40
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• pp.33.1-33.11
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• 2018

Background: Bimaxillary orthognathic surgery with maxillomandibular setback is often accompanied by changes in airway space. We analyzed the changes in airway space before and after surgery and assessed their association with obstructive sleep apnea. Methods: This study is based on the cohort of 13 adult patients (9 males, 4 females, average age 23.85 years) who underwent bimaxillary orthognathic surgery with maxillomandibular setback. We performed computed tomography and portable polysomnography before and after the surgery to assess changes in airway space and Apnea-Hypopnea Index (AHI) values (total, supine, non-supine). Results: The oropharyngeal airway volume decreased by 29% after the surgery, which was statistically significant (p < .05). The upper airway volume and hypopharyngeal airway volume were decreased, but not significantly (4 and 19%, respectively). The changes in airway surface area were statistically significant at all levels examined (p < .05). Changes in the maximum anteroposterior width of the airway were also significant at all levels (p < .05). However, the changes in maximum lateral width were only statistically significant at C2 level (p < .05). AHI values were increased after the surgery but not significantly at any position. Conclusions: Although bimaxillary surgery with maxillomandibular setback significantly reduces the airway space, it does not affect AHI values or induce obstructive sleep apnea.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.42
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• pp.7.1-7.8
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• 2020

Maxillomandibular advancement (MMA) is effective for the treatment of obstructive sleep apnea (OSA). In previous studies, the airway was increased in the anteroposterior and transverse dimensions after MMA. However, the effect of the opposite of mandibular movement (mandibular setback) on the airway is still controversial. Mandibular setback surgery has been suggested to be one of the risk factors in the development of sleep apnea. Previous studies have found that mandibular setback surgery could reduce the total airway volume and posterior airway space significantly in both the one-jaw and two-jaw surgery groups. However, a direct cause-and-effect relationship between the mandibular setback and development of sleep apnea has not been clearly established. Moreover, there are only a few reported cases of postoperative OSA development after mandibular setback surgery. These findings may be attributed to a fundamental difference in demographic variables such as age, sex, and body mass index (BMI) between patients with mandibular prognathism and patients with OSA. Another possibility is that the site of obstruction or pattern of obstruction may be different between the awake and sleep status in patients with OSA and mandibular prognathism. In a case-controlled study, information including the BMI and other presurgical conditions potentially related to OSA should be considered when evaluating the airway. In conclusion, the preoperative evaluation and management of co-morbid conditions would be essential for the prevention of OSA after mandibular setback surgery despite its low incidence.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.19 no.2
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• pp.117-129
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• 1997

Recently, combined with social complexity, increment of medical demand and supply and the change of esthetic category, admission and operation of the patients of facial deformity have been changed with annual change. This study was conducted in the concept of helping the overall character of orthognathic surgery in future understood and being an important index in the establishment of better treatment course, through the patient, on whom was operated orthognathic surgery via sagittal split ramal osteotomy in our Dept. of Oral & Maxillofacial Surgery, Chonbuk National University Hospital from 1991. 1. 1 to 1995. 12. 31. The results were obtained as follows. 1. The ratio of male to female was 1 : 1.33 and the ages between 16 and 25 year was 73.6%, and the mean age was 20.4 years. 2. The ratio of setback amount between 6 to 15mm was 84.6% and the advancement amount between 1 to 10mm was 89% and the mean amount of movement was 9.0mm in setback, and 3.6mm in advancement. 3. After removal of maxillomandibular fixation(MMF), the distinction of sex was not statistically significant in ROM. 4. The ROM following methods of fixation was statistically significant in 3rd(P<0.05), 8th, and 12th week(each P<0.01), with faster rehabilitation in rigid fixation which had shorter MMF period. 5. The rehabilitation of ROM following the operation methods was statistically significant in 1st(P<0.05), 2nd, 3rd, 4th, 6th, 8th, and 12th week(each P<0.01) with faster rehabilitation in the case of SSRO than Lefort I / SSRO (Two jaw surgery). 6. The rehabilitation of ROM following directions of mandibular movement did not manifest a statistically significant difference in both setback and advancement.

• The korean journal of orthodontics
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• v.44 no.6
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• pp.330-341
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• 2014

A 19-year-old woman presented to our dental clinic with anterior crossbite and mandibular prognathism. She had a concave profile, long face, and Angle Class III molar relationship. She showed disharmony in the crowding of the maxillomandibular dentition and midline deviation. The diagnosis and treatment plan were established by a three-dimensional (3D) virtual setup and 3D surgical simulation, and a surgical wafer was produced using the stereolithography technique. No presurgical orthodontic treatment was performed. Using the surgery-first approach, Le Fort I maxillary osteotomy and mandibular bilateral intraoral vertical ramus osteotomy setback were carried out. Treatment was completed with postorthodontic treatment. Thus, symmetrical and balanced facial soft tissue and facial form as well as stabilized and well-balanced occlusion were achieved.

• The korean journal of orthodontics
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• v.50 no.5
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• pp.324-335
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• 2020

Objective: To compare postoperative positional changes in the mandibular proximal segment between the conventional orthognathic surgery (CS) and the surgery-first approach (SF) using intraoral vertical ramus osteotomy (IVRO) in patients with Class III malocclusion. Methods: Thirty-eight patients with skeletal Class III malocclusion who underwent bimaxillary surgery were divided into two groups according to the use of preoperative orthodontic treatment: CS group (n = 18) and SF group (n = 20). Skeletal changes in both groups were measured using computed tomography before (T0), 2 days after (T1), and 1 year after (T2) the surgery. Three-dimensional (3D) angular changes in the mandibular proximal segment, condylar position, and maxillomandibular landmarks were assessed. Results: The mean amounts of mandibular setback and maxillary posterior impaction were similar in both groups. At T2, the posterior portion of the mandible moved upward in both groups. In the SF group, the anterior portion of the mandible moved upward by a mean distance of 0.9 ± 1.0 mm, which was statistically significant (p < 0.001). There were significant between-group differences in occlusal changes (p < 0.001) as well as in overjet and overbite. However, there were no significant between-group differences in proximal segment variables. Conclusions: Despite postoperative occlusal changes, positional changes in the mandibular proximal segment and the position of the condyles were similar between CS and SF, which suggested that SF using IVRO achieved satisfactory postoperative stability. If active physiotherapy is conducted, the proximal segment can be adapted in the physiological position regardless of the occlusal changes.