• 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.

• Imaging Science in Dentistry
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• v.35 no.4
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• pp.215-219
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• 2005

Hepatocellular carcinoma is one of the most common cancer worldwide, primarily affecting those in regions with a high prevalence of viral hepatitis. However, the metastasis of hepatocellular carcinoma to the oral cavity is a rare phenomenon. This report presents a case of metastatic hepatocellular carcinoma in the left mandibular angle and ramus region of a 62-year-old man. Panoramic radiograph revealed an ill-defined radiolucent lesion extending from the retained root of the mandibular left second molar into the ascending ramus. The lesion had irregular and ill-defined margins.

• The Journal of the Korean dental association
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• v.17 no.1 s.116
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• pp.29-34
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• 1979

• Journal of Korean Academy of Oral and Maxillofacial Radiology
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• v.29 no.1
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• pp.357-365
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• 1999

Desmoplastic fibroma is a rare. benign intraosseous fibroblastic tumor. which is locally aggressive. It is osseous counterpart of soft tissue fibromatosis. The authors experienced the patient who complained persistent mouth opening limitation with mild swelling on the left mandibular angle area. After careful analysis of clinical. radiological and histopathological findings. we diagnosed as desmoplastic fibroma of the mandible. The results were as follows: 1. Main clinical symptoms were mouth opening limitation which had been persistent for 9 months and mild swelling on the left mandibular angle area. 2. Radiographs showed the radiolucent lesion and expansion of lingual cortex. CT finding is homogeneous soft tissue mass with expansion of left mandibular ramus. Destruction of medial wall of ramus and invasion to adjacent soft tissue is also seen. 3. Histopathologically, plump spindle shaped fibroblasts arranged in bundles or fascicles are observed. The cells of tumor are infiltrating into muscle fiber with destruction of bony trabeculae and merged with surrounding salivary gland.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.38 no.5
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• pp.271-275
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• 2012

Objectives: This study evaluated a range of fixation methods to determine which is best for the postoperative stabilization of a mandibular osteotomy using three-dimensional finite element analysis of the stress distribution on the plate, screw and surrounding bone and displacement of the lower incisors. Materials and Methods: The model was generated using the synthetic skull scan data, and the surface model was changed to a solid model using software. Bilateral sagittal split ramus osteotomy was performed using the program, and 8 different types of fixation methods were evaluated. A vertical load of 10 N was applied to the occlusal surface of the first molar. Results: In the case of bicortical screws, von-Mises stress on the screws and screw hole and deflection of the lower central incisor were minimal in type 2 (inverted L pattern with 3 bicortical repositioning screws). In the case of plates, von-Mises stress was minimal in type 8 (fixation 5 mm above the inferior border of the mandible with 1 metal plate and 4 monocortical screws), and deflection of the lower central incisor was minimal in types 6 (fixation 5 mm below the superior border of the mandible with 1 metal plate and 4 monocortical screws) and 7 (fixation 12 mm below the superior border of the mandible with 1 metal plate and 4 monocortical screws). Conclusion: Types 2 and 6 fixation methods provide better stability than the others.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.41 no.3
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• pp.133-138
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• 2015

Objectives: To evaluate the influence of the type of osteotomy in the inferior aspect of the mandible on the mechanical performance. Materials and Methods: The study was performed on 20 polyurethane hemimandibles. A sagittal split ramus osteotomy (SSRO) was designed in 10 hemimandibles (group 1) with a vertical osteotomy in the buccal side (second molar level) and final osteotomy was performed horizontally on the lingual aspect, while the mandible body osteotomy was finalized as a straight osteotomy in the basilar area, perpendicular to the body. For group 2, the same osteotomy technique was used, but an oblique osteotomy was done in the basilar aspect of the mandibular body, forming continuity with the sagittal cut in the basilar area. Using a surgical guide, osteosynthesis was performed with bicortical screws using an inverted L scheme. In both groups vertical compression tests were performed with a linear load of 1 mm/min on the central fossa of the first molar and tests were done with models made from photoelastic resin. Data were analyzed using Student's t-test, establishing a statistical significance when P<0.05. Results: A statistical difference was not observed in the maximum displacements obtained in the two osteotomies (P<0.05). In the extensiometric analysis, statistically significant differences were identified only in the middle screw of the fixation. The photoelastic resin models showed force dissipation towards the inferior aspect of the mandible in both SSRO models. Conclusion: We found that osteotomy of the inferior aspect did not influence the mechanical performance for osteosynthesis with an inverted L system.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.30 no.3
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• pp.246-250
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• 2004

Uni- or bilateral mandibular hypoplasia can be associated with various syndromes or is acquired after early traumatic or inflammatory disease in the temporomandibular joint(TMJ). Early treatment is necessary to avoid consequent impairment of midfacial growth. The standard treatment of these malformations consists of the application of bone grafts which can lead to unpredictable growth, but the new procedure of bone lengthening which was presented by McCarthy et al. represents a limited surgical intervention and therefore open up a new perspective of treatment, especially in younger children with severe deformities. Patients with hemifacial microsomia and facial asymmetry have a vertically short maxilla, a tilted occlusal plane, and a short mandible. A 14-years-old boy with facial asymmetry, who was fractured on both condyle and mandibular symphysis before 8 years ago, was treated by mandibular ramus lengthening, symphysial widening and surgically assisted rapid palatal expansion with corticotomy. After allowing 1 week for the healing of the periosteum, the distraction was performed at the rate of 0.5-1.0mm per day for 7 days on maxilla and 14 days on mandible. The device was maintained on maxilla and mandible for 12 weeks following distraction. The difference in ramus and mandibular transverse deficiency were corrected and facial asymmetry was improved with complex distraction osteogenesis.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.31 no.5
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• pp.408-413
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• 2009

Odontogenic keratocyst (OKC) is a epithelial developmental cyst which were first described by Phillipsen in 1956. The frequency of OKC has been reported to vary from 3% to 11% of odontogenic cysts. The most characteristic clinical aspect of OKC is the high frequency of recurrence. The mechanism of recurrence is thought to be related to residues of cyst epithelium and an intrinsic growth potential following excision. And since the lining of the OKC is thin and friable, removal of the cyst in one piece may sometimes be difficult. Complete removal of the cyst lining without leaving behind remnants attached to the soft tissue or bone is necessary to avoid recurrence. Therapeutic approaches vary in different studies from marsupialization and enucleation, which may be combined with adjuvant therapy such as cryotherapy or Carnoy's solution, to marginal or radical resection. The recurrent rate varies from approximately 20% to 62%. And OKC in the angle-ramus region of the mandible had a higher tendency to recur, because of the difficulty in accessing and removing OKC from the ramus. By employing a sagittal splitting of the mandible a good surgical access was provided and cyst could be removed completely. We present an illustrative case of a small, lobulated OKC that involved ramus on mandible, and a review of the contemporary literature.

• Journal of Oral Medicine and Pain
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• v.24 no.2
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• pp.171-179
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• 1999

The authors experienced a oral carcinoma involving the medial cortex of the right ramus of mandible and the left side of the maxilla which was metastasized from primary rectal adenocarcinoma based on the comprehensive evaluation of data obtained from (1) the past medical history of primary rectal adenocarcinoma, (2) the computerized tomographic views of the homogeneous mass on the anteromedial region of the right ramus of mandible destructing the medial cortex of the right ramus of mandible, and the irregular mass around the clivus spreading into the sphenoid sinus and destructing the left side of the maxilla ; the bone scanning of hot spots on the nasal region and the left side of maxilla ; the posteroanterior chest radiographic view of multiple nodular radiopacities on the lung, (3) the retrospective review of the sonographic view of a hypoechoic, well-demarcated, target-like mass with central hyperechoic focus on right lobe of liver in a Korean female of 49-year-old who complained the ptosis of left eyelid, the swelling on left zygomatic area, the left facial paralysis, the facial asymmetry and a round-shaped, elevated lesion with a hematoma on the mucosa covering the right ramus of mandible.

• Journal of the korean academy of Pediatric Dentistry
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• v.38 no.4
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• pp.368-375
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• 2011

The aim of this study was to evaluate the position of the mandibular foramen in panoramic radiographs of Korean children to provide information for successful inferior alveolar nerve block anesthesia. 240 panoramic radiographs of 7 to 15-year-old boys and girls were analyzed. The subjects were divided into 4 groups in boys and girls according to their age.; 7-8, 9-10, 11-12 and 13-15 years old. The shortest distances from the center of the mandibular foramen to the anterior border of ramus, to the posterior border of ramus, to the antegonial notch and to the mandibular notch and the perpendicular distances from the center of the mandibular foramen to the occlusal plane were measured. The following results were obtained. 1) Although the relative position of the mandibular foramen in the ramus of mandible tended to move anteriorly for both genders with age, the vertical position did not correlate with age. 2) The mandibular foramen moved upward in relation to the occlusal plane with age, and showed statistically significant correlation with age(p<0.05). 3) The mandibular foramina of boys, when compared to those of girls, were located more superiorly in relation to the occlusal plane and more superiorly and posteriorly in the ramus of mandible.