• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• 제38권6호
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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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• 제27권3호
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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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• 제30권3호
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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.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• 제33권2호
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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.

• Journal of Korean Dental Science
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• 제3권2호
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• pp.4-11
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• 2010

Purpose: This study aimed at examining the thickness of lateral cortical bone in the mandibular posterior body and the location of the inferior alveolar nerve canal as well as investigating the clinically viable bone grafting site(s) and proper thickness of the bone grafts. Subjects and Methods: The study enrolled a total of 49 patients who visited the Department of Oral and Maxillofacial Surgery at Kyung Hee University Dental Hospital to have their lower third molar extracted and received cone beam computed tomography (CBCT) examinations. Their CBCT data were used for the study. The thickness of lateral cortical bone and the location of inferior alveolar nerve canal were each measured from the buccal midpoint of the patients' lower first molar to the mandibular ramus area in the occlusal plane of the molar area. Results: Except in the external oblique ridge and alveolar ridge, all measured areas exhibited the greatest cortical bone thickness near the lower second molar area and the smallest cortical bone thickness in the retromolar area. The inferior alveolar nerve canal was found to be located in the innermost site near the lower second molar area compared to other areas. In addition, the greatest thickness of the trabecular bone was found between the inferior alveolar nerve canal and the lateral cortical bone. Conclusions: In actual clinical settings involving bone harvesting in the posterior mandibular body, clinicians are advised to avoid locating the osteotomy line in the retromolar area to help protect the inferior alveolar nerve canal from damage. Harvesting the bone near the lower second molar area is judged to be the proper way of securing cortical bone with the greatest thickness.

• Imaging Science in Dentistry
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• 제31권4호
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• pp.215-219
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• 2001

Purpose: The objective of this study was to estimate the radiation absorbed doses in certain critical organs in the head and neck region with 16 imaging programs available on the Orthopos/sup (R)/ panoramic machine. Materials and Methods: A Rando phantom and LiF TLD chips were used for dosimetry. The absorbed doses were measured at the thyroid gland, the submandibular gland, the parotid gland, the mouth floor. the maxillary sinus, the brain, the mandibular body, the mandibular ramus. the 2nd cervical spine and the skin over TMJ area. Results : The overall absorbed doses with imaging programs available on the Orthopos/sup (R)/ panoramic machine were much less than that of standard program (program 1) except program 8, 11, and 16. Generally, the absorbed doses to the bone marrow of the mandibular ramus and the parotid gland were high, but the absorbed doses to the bone marrow in the mandibular body, brain, maxillary sinus, and, especially, the thyroid gland were very low. Conclusion : The modified imaging programs available on the Orthopos/sup (R)/ panoramic machine can be effectively used in aspect of radiation protection.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• 제36권2호
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• pp.94-99
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• 2010

The purpose of this study was to examine the soft tissue changes in skeletal class II patients after mandibular advancement by bilateral sagittal split ramus osteotomy (BSSRO). In Asian population, the incidence of skeletal class II malocclusion is lower than that of skeletal class III malocclusion unlike the caucasians. This study was conducted to figure out the ratio at which hard tissue and soft tissue changes after mandibular advancement by analyzing cephalograms of 13 patients that have undergone the mandibular advancement surgery. As a result, change ratios of Li, B', Pog' according to the movement of li, B, Pog were found to be 0.59, 1.06, 0.82. Also, vertical height of vermilion zone (Si-Vb) and lower lip and chin (Si-Me') were measured to evaluate vertical changes. Vermilion zone showed tendency to decrease by 1.02 mm on the average postoperatively, whereas vertical length of lower lip and chin showed tendency to increase by 3.57 mm on the average.

• Maxillofacial Plastic and Reconstructive Surgery
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• 제41권
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• pp.8.1-8.6
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• 2019

Background: Resorbable devices have recently been adopted in the field of orthognathic surgery with controversies about their postoperative skeletal stability. Hence, we determined the long-term skeletal stability of unsintered hydroxyapatite/poly-ʟ-lactic acid (HA/PLLA) mesh for osteofixation of mandibular sagittal split ramus osteotomy (SSRO), and compared it with that of titanium miniplate. Methods: Patients were divided into resorbable mesh and titanium miniplate fixation groups. A comparative study of the change in the mandibular position was performed with preoperative, 1-day, 6-month, and 2-year postoperative lateral cephalograms. Results: At postoperative 6 months-compared with postoperative 1 day, point B (supra-mentale) was significantly displaced anteriorly in the titanium-fixation group. Moreover, at postoperative 2 years-compared with postoperative 6 months, point B was significantly displaced inferiorly in the titanium-fixation. However, the HA/PLLA mesh-fixation group did not show any significant change with respect to point B postoperatively. Conclusions: The HA/PLLA mesh-fixation group demonstrated superior long-term skeletal stability with respect to the position of mandible, when compared with the titanium-fixation group.

• 한국임상수의학회지
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• 제25권6호
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• pp.545-548
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• 2008

A 3-year-old castrated male Siberian husky was presented for evaluation after being hit by a car. On physical examination, the dog showed open-mouth, displacement of mandible and hypersalivation with blood ting. The base of tongue was transected almost 80% on the bias from right dorsal side to the left ventral side. Radiography demonstrated separation of mandible symphysis, and fracture of right condyle and vertical ramus. After debridement of the necrotic tissue, tongue apposition with simple interrupted suture was performed. Mandibular symphysis, condyle and mandibular vertical ramus fractures were fixed using pin, cerclage wire, T-plate, and K-wires. The mouth was irrigated daily using chlorhexidine after surgery. The sutures that were loose here or untied at tongue were re-sutured under sedation. The transected tongue was healed and recovered its normal movement after 6 weeks.

• 대한치과교정학회지
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• 제40권4호
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• pp.227-238
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• 2010

저신장이란 같은 연령 및 성별 소아들의 표준 신장 평균치에서 -2.0 SD 이하인 경우를 말한다. 본 연구의 목적은 저신장 소아의 두개안면골격의 특성을 분석하고, 성장호르몬 치료가 신장을 성장시킴과 동시에 두개안면골격에 어떤 영향을 주는지 알아보고자 함이다. 영남대학교 의과대학 부속병원 소아청소년과에서 저신장으로 진단받은 소아를 대상으로 성장 호르몬 치료 전 그리고 치료 후 1년, 2년 후 총 3회 측모 두부 방사선 규격 사진의 촬영을 시행하였다. 대조군은 경북대학교 치의학전문대학원 교정과에 소장된 한국인 평균 신장의 2 표준오차 내의 아동들을 대상으로 측모 두부 방사선 규격사진을 2년마다 10년간 촬영한 자료를 이용하여 저신장 소아의 연령과 성별을 기준으로 짝진 표집(paired sampling)을 하였다. 성장 호르몬 치료 전 저신장 소아는 작고 후퇴된 하악골과 편평한 두개저를 가지는 것으로 나타났다. 성장 호르몬 치료 후 anterior, posterior cranial base length, upper posterior facial height, lower anterior facial height, posterior total facial height, mandibular ramus length, mandibular corpus length와 overall mandibular length 성장량이 정상군에서의 2년 성장량과 비교했을 때 유의하게 큰 것으로 나타났으며 각도 계측에서는 saddle angle, mandibular plane angle과 ANB변화량이 정상군에서의 2년 성장량과 비교했을 때 큰 변화를 보이며 정상군의 평균치를 따라잡는 경향을 보였다. 성장 호르몬 치료는 불균형적인 성장의 징후 없이 정상화를 향한 성장(따라잡기 성장)을 나타내었으며 이는 특히 하악과두의 성장과 후안면고경의 성장을 촉진시켜 저신장 소아의 convex한 profile을 완화하는 것으로 판단된다.