• The korean journal of orthodontics
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• v.20 no.1
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• pp.135-156
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• 1990

This study was undertaken to investigate the difference of chin morphology and mandibular form in relation to different mandibular growth direction. The subject was divided into three group i.e., control group, vertical group, and horizontal group, according to the criteria of $Bj{\ddot{o}}rk$ sum, and each group was composed of 15 females and 15 males. Medial axis analysis in addition to the routine cephalometric analysis using P.I.A.S. (personal image analysing system) was carried out to find out the differences of mandibular morphology on each group. The results were as follows: 1. The area of symphysis was larger in horizontal growth group than that of vertical growth group. 2. Protruding chin area was also larger in horizontal growth group than that of vertical growth group. 3. There was a close correlationship between protruding chin area and other form of mandible. 4. Antegonial notch depth and ramus posterior contour depth was deeper in vertical growth group than in horizontal growth group, and antegonial notch depth was more influenced by anterior part of notch than posterior part of notch. 5. Mental medial axis and incisal medial axis length, in relation to corpus medial axis length was larger in vertical growth group than in horizontal growth group.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.31 no.4
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• pp.312-315
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• 2005

A squamous odontogenic tumor (SOT) is rare disease and it is believed to originate from epithelial rests of Malassez of the periodontal membrane. Neither sex nor site predilection in either jaw has been established. Some lesion can be shown in juxtaposition in tooth roots. Although most lesions remain smaller than 2 cm, our cases involved a half of left mandibular ramus. The exact pathogenesis is still unknown. We report a case of SOT including the results of immunohistochemical study of pancytokeratin and p53.

• The korean journal of orthodontics
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• v.18 no.2
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• pp.343-366
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• 1988

Craniofacial complex is influenced by numerical skeletal elements. Though the analysis of growth change has been done by various analytical methods, it was dependent on any method of registration and superimposition, based on reference plane and reference point. However, the craniofacial growth is composed of a number of local growth elements. Therefore, it will be necessary to use a clinically useful method for estimating craniofacial skeletal growth independently. The author analysed longitudinal cephalometric roentgenogram of 15 Korean males and 15 Korean females aged from 6 to 12 years by the finite element method and results were as follows : 1. The finite element method for craniofacial skeletal complex and soft tissue made it possible to analyze the independent local growth. 2. Regression equations from the value of each strain will make it possible to predict the craniofacial growth. 3. The growth of anterior cranial base was different from that of other facial bone. 4. The growth of posterior cranial base influenced the growth of upper pharyngeal region, midfacial region, maxilla and posterior region of mandible. 5. The growth of maxillary complex was vertical rather than horizontal. 6. The growth direction of ramus, mandibular body, alveolar bone was various. 7. The relation between hard tissue and soft tissue by finite element method was variant.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.11 no.1
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• pp.69-77
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• 1989

This is a retrospective study on 219 patients with mandibular fracture. The patients were treated in the Dept. of Oral Maxillofacial Surgery of WON KWANG UNIV. HOSPITAL from Aug. 1, 1984 to Sept. 30. 1988. The results were as follows. 1. The mandibular fractures occured most frequently in the twenties(35%) and male were predominant (74.7%) than females. 2. The most frequent etiologic factor was traffic accident(34.3%). 3. The most common location of fracture was symphysis(37.1%). And angle(27.6%), condyle(25.7%), ramus(1.6%) were next in order of frequency. 4. In mandible fracture, they have an average 1.8 fracture line. 5. The use of plate & screw system were more increased in the comparison of each year. 6. Intermaxillary fixation period was more reduced from the concept of 6 weeks fixation, due to the use of Plate & screw system. 7. Postoperative acute wound infection was developed 9.6% in 219 mandibular fracture patients. The compression osteosynthesis was most common cause of acute wound infection than any other treatment method. 8. Postoperative malocclusion was developed 4% in 219 mandibular fracture. And the compression osteosynthesis was most common cause of malocclusion. 9. Acute wound infection was detailed by the approach method. The Intraoral & extraoral combination method was most common cause on acute infection and intraoral, extraoral approach method was next in order of frequency. 10. Normal mouth opening process was proportioned to IMF period. The short IMF period have a fast normal mouth opening process.

• The korean journal of orthodontics
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• v.19 no.1 s.27
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• pp.219-243
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• 1989

The purpose of this study was to evaluate the effects of the chincap therapy on the craniofacial structure in persons with skeletal Class III malocclusion. The patients selected for this study were treated with extra-oral chincap therapy only. Both control and treatment samples were obtained from Seoul National University Hospital where these longitudinal data were gathered. 55 treated patients and 14 control patients were studied. The mean ages at the 1st evaluation was 8 years 3 months in the treatment sample and 9 years 4 months in the control sample. The duration of chincap therapy was variable but averaged 2 years of treatment. Post-treatment observation procedeeded for 1 year 2 months. Active treatment and post treatment effects were evaluated. The results were as follows: 1. Neither significant restraint nor acceleration of growth was found in the cranial base and maxilla during treatment. 2. A distal rotation of the mandibular complex was seen. 3. Some amount of restraint of growth was found in mandibular body length, ramus height, mandibular length during treatment. 4. The genial angle was reduced. 5. After removal of the chin-cap, forward displacement of the mandible took place.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.22 no.2
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• pp.184-190
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• 2000

Objective : To compare two different methods of rigid fixation in postoperative stability after mandibular setback. Material and Methods : 28 patients with Class III malocclusion were treated by bilateral sagittal split ramus osteotomy(BSSRO) and mandibular setback were selected for this study. Group A(n=14) had the bone segments fixed with monocortical miniplate on the lateral side of the mandibular body and Group B(n=14) had three noncompressive bicortical screw inserted at the genial area through a transcutaneous approach. Cephalograms were taken preoperatively, postoperatively within 1 weeks and at a follow-up period (mean 8.9 months after surgery) and the amount of setback and postoperative change were measured. Results : Postoperative relapse between two groups was minimal in setback of the mandible. Statistical analysis showed no significant difference in postoperative relapse. Conclusion : This study suggests that both methods of skeletal fixation investigated give comparable postoperative stability and their use in mandibular setback appears to be a fairly stable clinical procedure .

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.43 no.2
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• pp.115-119
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• 2017

Maxillofacial images must be examined to find pathologies not identified during clinical examination. Unicystic ameloblastoma (UA) extending to the mandibular body and ramus was neglected on initial panoramic radiographic examination. After orthodontic therapy, a huge lesion was observed clinically and through imaging exams. After the conservative surgery, no recurrence was observed during five years of follow-up. This case emphasized the need for careful evaluation of patient images focusing on the oral diagnosis before any dental treatment planning, including orthodontic therapy.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.31 no.6
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• pp.485-491
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• 2009

Postoperative skeletal stability was evaluated in combination of Le Fort I and U-shaped osteotomies for superior repositioning of maxilla in bi-maxillary surgeries in 30 consecutive patients. The fifteen patients underwent Le Fort I osteotomy alone and the other fifteen patients underwent Le Fort I and U-shaped osteotomies. In all patients, the maxilla was first osteomized and fixed with absorbable plates system. A bilateral sagittal split ramus osteotomy (BSSRO) of the mandible was then carried out and fixation was performed using absorbable plates. Maxillo-mandibular fixation with rubber ring was used for two weeks post-operatively in all patients. Lateral cephalograms were obtained pre-operatively, 1 day post-operatively, 6 months after surgery. The changes in anterior nasal spine (ANS), point A, upper incisior (U1), and point of maxillary tuberosity (PMT) were examined. The maxillas in the fifteen patients of both examination group were repositioned nearly in their planned positions during surgery and no significant post-operative changes in the examined points of the maxilla were found. These results suggest that a combination of a Le Fort I and U-shaped osteotomy is a useful technique for reliable superior repositioning of the maxilla. The post-operative change in the maxilla using this combination osteotomy was comparatively stable.

• The Journal of Advanced Prosthodontics
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• v.5 no.3
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• pp.333-340
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• 2013

PURPOSE. This study was accomplished to assess the biomechanical state of different retaining methods of bar implant-overdenture. MATERIALS AND METHODS. Two 3D finite element models were designed. The first model included implant overdenture retained by Hader-clip attachment, while the second model included two extracoronal resilient attachment (ERA) studs added distally to Hader splint bar. A non-linear frictional contact type was assumed between overdentures and mucosa to represent sliding and rotational movements among different attachment components. A 200 N was applied at the molar region unilaterally and perpendicular to the occlusal plane. Additionally, the mandible was restrained at their ramus ends. The maximum equivalent stress and strain (von Mises) were recorded and analyzed at the bone-implant interface level. RESULTS. The values of von Mises stress and strain of the first model at bone-implant interface were higher than their counterparts of the second model. Stress concentration and high value of strain were recognized surrounding implant of the unloaded side in both models. CONCLUSION. There were different patterns of stress-strain distribution at bone-implant interface between the studied attachment designs. Hader bar-clip attachment showed better biomechanical behavior than adding ERA studs distal to hader bar.

• Journal of Korean Academy of Oral and Maxillofacial Radiology
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• v.25 no.1
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• pp.17-25
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• 1995

The purpose of this study was to obtain some informations for the radiographic differential diagnosis between odontogenic keratocyst and unicystic ameloblastoma in the mandible. The author compared and analysed the clinico-radiographic features of 48 cases of odontogenic keratocyst and 32 cases of unicystic ameloblastoma. The obtained results were as follows : 1. Odontogenic keratocyst and unicystic ameloblastoma occurred the most frequently in the 2nd and 3rd decades, and both lesions occurred with slight predilection in males. The most frequent lesional site was molar area in odontogenic keratocyst(50.0％) and mandibular angle and ramus area in unicystic amelobla-stoma(71.9％). 2. Cortical thinning and expansion were observed with similar occurrences in odontogenic keratocyst(77.l％) and in unicystic ameloblastoma(72.9％). 3. Typical undulating lesional border was observed more frequently in odontogenic keratocyst(79.2％) than in unicystic ameloblastoma(46.9％). 4. Well-defined lesional outline occurred more frequently in odontogenic keratocyst(97.9％) than in unicystic ameloblastoma(53.1％). 5. Root resorption of adjacent teeth occurred more frequently in unicystic ameloblastoma(65.2％) than in odontogenic keratocyst(18.8％) respectively, but loss of lamina dura was frequently observed in odontogenic keratocyst(79.2％). And tooth displacement occurred more frequently in odontogenic keratocyst(50.0％) than in unicystic ameloblastoma(17.4％). 6. Displacement of mandibular canal occurred more frequently in odontogenic keratocyst(75.0％) than in unicystic ameloblastoma(61.5％). 7. Inhomogeneous lesional radiolucency occurred more frequently in unicystic ameloblastoma(53.l％) than in odontogenic keratocyst(39.6％).