• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.39 no.5
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• pp.217-223
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• 2013

Objectives: Buccal fracture of the mandibular proximal bone segment during bilateral sagittal split ramus osteotomy (SSRO) reduces the postoperative stability. The primary aim of this study is to evaluate the effect of this type of fracture on bone healing and postoperative stability after mandibular setback surgery. Materials and Methods: Ten patients who experienced buccal fracture during SSRO for mandibular setback movement were evaluated. We measured the amount of bone generation on a computed tomography scan, using an image analysis program, and compared the buccal fracture side to the opposite side in each patient. To investigate the effect on postoperative stability, we measured the postoperative relapse in lateral cephalograms, immediately following and six months after the surgery. The control group consisted of ten randomly-selected patients having a similar amount of set-back without buccal fracture. Results: Less bone generation was observed on the buccal fracture side compared with the opposite side (P<0.05). However, there was no significant difference in anterior-posterior postoperative relapse between the group with buccal fracture and the control group. The increased mandibular plane angle and anterior facial height after the surgery in the group with buccal fracture manifested as a postoperative clockwise rotation of the mandible. Conclusion: Bone generation was delayed compared to the opposite side. However, postoperative stability in the anterior-posterior direction could be maintained with rigid fixation.

• Imaging Science in Dentistry
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• v.46 no.2
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• pp.77-85
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• 2016

Purpose: To analyze the relative position of the mandibular foramina (MnFs) in patients diagnosed with skeletal class III malocclusion. Materials and Methods: Computed tomography (CT) images were collected from 85 patients. The vertical lengths of each anatomic point from the five horizontal planes passing through the MnF were measured at the coronoid process, sigmoid notch, condyle, and the gonion. The distance from the anterior ramus point to the posterior ramus point on the five horizontal planes was designated the anteroposterior horizontal distance of the ramus for each plane. The perpendicular distance from each anterior ramus point to each vertical plane through the MnF was designated the horizontal distance from the anterior ramus to the MnF. The horizontal and vertical positions were examined by regression analysis. Results: Regression analysis showed the heights of the coronoid process, sigmoid notch, and condyle for the five horizontal planes were significantly related to the height of the MnF, with the highest significance associated with the MnF-mandibular plane (coefficients of determination ($R^2$): 0.424, 0.597, and 0.604, respectively). The horizontal anteroposterior length of the ramus and the distance from the anterior ramus point to the MnF were significant by regression analysis. Conclusion: The relative position of the MnF was significantly related to the vertical heights of the sigmoid notch, coronoid process, and condyle as well as to the horizontal anteroposterior length of the ascending ramus. These findings should be clinically useful for patients with skeletal class III mandibular prognathism.

• Journal of Dental Rehabilitation and Applied Science
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• v.22 no.4
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• pp.271-281
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• 2006

Long term prediction of surgical result of skeletal class III has not been evaluated adequately because the stability of orthognathic surgery would be affected by not only set back amount of mandible but also many other factors like skeletal pattern, hyoid position, and airway size. The aimof this study is to discriminate the factors which affect the stability of post-treatment result of surgical outcome of sagittal split ramus osteotomy. We have collected 37 patients (male: 17, female: 20) from patients who have been treated at Orthodontic Department in Dankook University. The patients underwent 3 times Cephalometric X-ray taking at pre-, post-orthognathic surgery and after 12 months retention. The subjects were divided into 2 groups (Stable group: 21, Relapse group: 16) according to their relapse amount. We have taken following results from Students t-test and discriminant analysis. The discriminant factors which discern relapse and stable groupe among treatment change variables were BX and Ba-HY. Hyoid bone moved to posterior and inferior position due to surgery and repositioned superiorly and posteriorly during retention period. Skeletal patterns of the relapse group are smaller mandibular plane angle, anterior mandibular position, and greater distance from hyoid bone to cervical bone and mandible respectively.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.30 no.1
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• pp.100-107
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• 2008

First of all a good surgical access is considered among various approach methods to the cystic lesion. A poor surgical access can lead to a failure of the whole treatment. A sagittal split ramus osteotomy (SSRO) on the large cyst occurring in the mandibular ramus lets us not only reduce operation time, but can additionally contribute to a good visual field. In addition, a merit exists that it lets this operating method provide soft tissue adhesion for proximal and distal segment and decrease post operative necrosis. We experienced three cases of a large cyst on the mandibular angle and ramus. By employing a sagittal splitting of the mandible, it provided good surgical access and operation results without recurrence during a follow-up period. The surgical technique described may be helpful in treating similar large cysts.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.32 no.4
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• pp.351-358
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• 2010

A 31-year-old woman with hemifacial microsomia presented to the Department of Oral and Maxillofacial Surgery, Seoul National University Dental Hospital. The patient was previously treated with distraction osteogenesis device to elongate right maxilla and mandibular ramus. But, the result was not satisfactory, to correct residual facial asymmetry due to hemifacial microsomia we planned costochondral graft for reconstruction of ramus and condyle, Le Fort I osteotomy and sagittal split ramus osteotomy for facial asymmetry. The right mandibular condyle and ramus was reconstructed with right eleventh costochondral graft via submandibular approach. Using costochondral graft and orthognathic surgery the facial asymmetry in hemifacial microsomia patient was corrected. 1-stage treatment consists of costochondral graft and orthognathic surgery can achieve function and esthetics at the same time, is timesaving to both patient and surgeon.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.38 no.6
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• pp.354-359
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• 2012

Objectives: The purpose of this study was to investigate whether the age factor would be related with stability of mandibular setback surgery for patients with mandibular prognathism. Materials and Methods: We compared the relapse patterns of 47 patients divided into three age groups (termed younger, adult, and older). The younger group consisted of patients between 15 and 17 years old; the adult group was made up of patients between 21 and 23 years old, and the older group was made up of patients more than 40 years old. The positional change of B point was evaluated at preoperative, postoperative, and follow-up states. Results: The horizontal relapse ratio was 21.7% in the younger group, 15.3% in the adult group, and 15.7% in the older group. Although relatively higher degrees of relapse were found in the younger group, this increase was not statistically significant. Spearman's correlation analysis was performed to explore other factors contributing to relapse. We subsequently found that the amount of relapse was related to horizontal setback. Conclusion: Although the degree of relapse in younger patients is not significant;y higher compared to other groups. The major contributing factor to relapse after sagittal split ramus osteotomy is amount of setback rather than age when the surgery was performed to patients over than 15 years of age.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.27 no.3
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• pp.258-265
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• 2001

A prognathic mandible and prominent gonial angle are considered to be unattractive in the Orient because it gives the face a square and muscular appearance. Requests for contouring of the mandibular angle are rare in the other race but are much more common in Korea and, through out the Orient. So, we often encounter a patient with a prognathic mandible and squarish or broad face who wishes to have his or her facial size reduced minimally or to acquire a round or slender appearance. But, mandibular angle is located in the deepest part of the operative field and the strong tension of the lateral soft tissue makes retraction difficult. It is extremely difficult to reduce the gonial angle with sagittal split ramus osteotomy by intraoral approach at the same time. We apply the method of gonial angle reduction during SSRO and had satisfactory results. We will present our results and hope to give some useful information for management of mandibular deformity.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.33 no.2
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• pp.109-113
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• 2007

Introduction. In patients with mandibular prognathism, Bilateral Sagittal Split Ramus Osteotomy(BSSRO) combined with orthodontic treatment reduces oral volume and influences tongue and other surrounding tissues. Purpose of this study was to analyze post-operative tongue position and airway dimension, as well as mandibular changes in vertical, horizontal, and angular dimensions. Materials and methods. Height of dorsum of tongue, width of airway, gonial angle and lower facial height of mandibular prognathic patients who visited Kangdong Sacred Heart Hospital from Jan. 2001 to Dec. 2006 were anaylzed via pre-operative and post-operative cephalograms. T-test was used to compare pre-operative and post-operative measurements. Also, correlations among pre-operative measurements of the patients were analyzed. Results and conclusion. A significant correlation was shown between ANS-Xi-PM area and location of dorsum of tongue in pre-operative patients. A significant superior movement of tongue and decrease of airway width was observed in post-operative patients. Also the upper gonial angle decreased significantly.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.23 no.2
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• pp.169-173
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• 2001

Maxillary-malar deficiency is the most frequently occurring midface dentofacial deformity. Clinicaly patients with maxillary-malar deficiency exhibit malar and infraorbital rim deficiency and class III malocclusion. For treatment of these deformities, modified LeFort III osteotomy have been used. Modified LeFort III osteotomy advances maxilla with orbital rims and zygomatic bone anteroposteriorly. This is a case of patient who had severe mandibular prognthism with midface deformity. We performed modified LeFort III osteotomy for maxillary-malar advancement and simultaneous bilateral sagittal split ramus osteotomy for mandibular prognathism and autogenous iliac bone graft.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.13 no.2
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• pp.191-198
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• 1991

This is a case report and review of literature of the facial asymmetry corrected by various surgical methods. In case 1, facial asymmetry resulted from osteochondroma of condyle and corrected via condylectomy only. In case 2, unilateral condylar hyperplasia with compensatory maxillary growth resulted in severe facial asymmetry. Procedures used in case 2 are vertical ramus osteotomy, condylectomy, genioplasty, mandibular inferior border ostectomy and Le Fort I osteotomy.