• The korean journal of orthodontics
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• v.26 no.6
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• pp.691-703
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• 1996

Three-dimensional finite element model was made from adult skull to find desirable direction of retraction force to treat skeletal class II malocclusion. The retraction force of 400g was applied to the first molar. The direction of the force application was $23^{\circ}$ downward, parallel, $23^{\circ}$ upward and $45^{\circ}$ upward to the occlusal plane. The stress distribution and the displacement within the maxilla were analyzed by three-dimensional finite element method. The findings obtained were as follows: 1. Maxillary first molar was displaced posteriorly and inferiorly in $23^{\circ}$ downward, parallel, $23^{\circ}$ upward retraction but it was displaced posteriorly and superiorly in $45^{\circ}$ upward retraction. 2. ANS, A point and prosthion were moved posteriorly and inferiorly and pterygomaxillary fissure was moved posteriorly and superiorly. Clockwise rotation of maxilla occurred when retraction force was applied. 3. The degree of clockwise rotation of maxilla was greatest when the force was applied $23^{\circ}$ upward to the occlusal plane and was least when the force was applied $23^{\circ}$ downward to the occlusal plane. 4. Large tensile stress appeared in maxillary first molar and alveolar bone and the infraorbital region of maxilla when the force was applied $23^{\circ}$ downward to the occlusal plane. Tensile stress was smaller as the direction of force move upward. 5. Large compressive stress was appeared in maxillary first molar and infraorbital region in $45^{\circ}$ upward case and large compressive stress occurred in the posterior part of maxilla as the retraction force was upward.

• Archives of Craniofacial Surgery
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• v.10 no.2
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• pp.131-134
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• 2009

Purpose: Mandible fractures are common in maxillofacial trauma and the incidence of condylar fracture is high. The management of mandibular condylar fracture continues to be controversial. Conservative treatment of it may lead to complications such as asymmetry, malocclusion, temporomandibular joint dysfunction. Moreover, open reduction can cause facial nerve injury, parotid gland injury, scarring and hematoma formation. We present a case of mandibular condylar fracture that was treated by manual reduction without incision under C-arm fluoroscopy. Methods: A 76-year-old female was admitted due to left side mandibular condylar fracture that required surgical intervention. Because of her age, history of diabetes mellitus, hypertension, she underwent closed manual reduction under general anesthesia. We adopted C-arm fluoroscopy as a method of identifying the fracture site and a evaluation of reduction state. C-arm fluoroscopy was set up like modified Towne's view. Results: The reduction was successful and didn't result in any complications that could occur in open reduction-facial nerve injury, infection, parotid gland injury, hematoma, avascular necrosis. The mandibular-maxillary fixations were removed after 4 weeks and patients were could open 3.5 cm after 6 weeks with physical therapy. Conclusion: We tried closed manual reduction of mandibular condylar fracture due to high risk of complication using C-arm fluoroscopy and did achieve anatomic reduction with avoiding open incision. This is simple, effective, reversible, time saving and fairly attemptable method in condylar fracture cases before open reduction.

• Archives of Craniofacial Surgery
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• v.10 no.2
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• pp.76-80
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• 2009

Purpose: Zygoma is a major portion of the midfacial skeleton, forms the malar prominence and the three adjacent bony articulations. Zygoma fracture is a very common in facial trauma. Open reduction and rigid fixation of displaced zygoma fractures are necessary to avoid immediate and delayed facial asymmetry and depression. However, it is possible to happen the complications related to the plates and screws. So, we planned to treat the 24 patients of Group II, III, IV zygoma fractures with precise reduction and non-fixation method via intraoral approach. Methods: From August, 2006, to August, 2009, we treated 24 cases of zygoma fracture with reduction and non-fixation methods. Before the surgery, we choose the patients who could be treated with this method among the Group II, III, IV patients. Results: No patients in this study had postoperative complications such as displacement of bony fragments, facial depression and asymmetry, malocclusion, hypoesthesia. Satisfactory aesthetic and functional results can be obtained. Conclusion: In the treatment of the zygoma fracture, it is possible to treat with precise reduction and non-fixation method. The greatest advantage is to decrease the operative time, no need to wide dissection, no complications related to the plates and screws. For the using of this method, it is necessary to choose the adequate patients through the preoperative planning.

• The korean journal of orthodontics
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• v.43 no.6
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• pp.279-287
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• 2013

Objective: To investigate the dentoskeletal factors which may predict soft-tissue chin strain during lip closure. Methods: The pretreatment frontal and lateral facial photographs and lateral cephalograms of 209 women (aged 18-30 years) with Angle's Class I or II malocclusion were examined. The subjects were categorized by three examiners into the no-strain and strain groups according to the soft-tissue chin tension or deformation during lip closure. Relationships of the cephalometric measurements with the group classification were analyzed by logistic regression analysis, and a classification and regression tree (CART) model was used to define the predictive variables for the group classification. Results: The lower the value of the overbite depth indicator (ODI) and the higher the values of upper incisor to Nasion-Pogonion (U1-NPog, mm), overjet, and upper incisor to upper lip (U1-upper lip, mm), the more likely was the subject to be classified into the strain group. The CART showed that U1-NPog was the most prominent predictor of soft-tissue chin strain (cut-off value of 14.2 mm), followed by overjet. Conclusions: To minimize strain of the soft-tissue chin, orthodontic treatment should be oriented toward increasing the ODI value while decreasing the U1-NPog, overjet, and U1 upper lip values.

• The Journal of Korean Academy of Prosthodontics
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• v.8 no.1
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• pp.56-64
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• 1968

저자(著者)는 구개도(口蓋圖)에 의(依)하여 한국어(韓國語) 마찰음(摩擦音)의 라, 사, 자, 차 사행(四行), 도합(都合) 40음(音)에 대(對)한 정당교합자(正堂咬合者) 오인(五人)과 부정교합자(不正咬合者) 십칠인(十七人)의 발음(發音)을 조사(調査)하여 다음과 같은 결과(結果)를 얻었다. 1) 라, 사, 자, 차 사행(四行)의 구개도(口蓋圖)는 V, H 및 C형(型)을 나타낸다. 2) 라행(行)의 구개도(口蓋圖)는 교합군(咬合群)에 관계(關係)없이 주(主)로 H형(型)을 보인다. 라행(行)에 있어서 전치(前齒)와 접촉부위간(接觸部位間)의 거리는 과개교합군(過蓋咬合群)에서 크고, 반대교하군(反對咬合群)에서는 작다. 3) 사행(行)은 주(主)로 V형(型)을 보이며 반대교합군(反對咬合群)에서만 C형(型)이 1/3정도(程度) 나타난다. 반대교합군(反對咬合群)에서의 V형(型)은 그 접촉부위(接觸部位)가 구치부(臼齒部)로 갈수록 두터워 진다. 4) 자, 차행(行)의 구개도(口蓋圖)는 라, 사행(行)에 비(比)하여 변화(變化)가 많다. a) 과개교합군(過蓋咬合群)은 H형(型)이 67%이고 나머지는 C형(型). b) 반대교합군(反對咬合群)은 거의 모두가 C형(型). c) 과개교합군(寡蓋咬合群)에서는 반이상(半以上)이 C형(型), 나머지는 H형(型)이나 간혹 V형(型)도 출현(出現)한다. 5) 구치부(臼齒部)에서의 측방반대교합(側方反對咬合)의 경우는 반대교합(反對咬合)이 있는 반대(反對)쪽의 접촉부위(接觸部位)가 넓다. 6) 과개교합군(寡蓋咬合群)에서의 접촉부위(接觸部位)는 정상군(正常群)이나 과개교합군(過蓋咬合群)에서 보다 일반적(一般的)으로 넓게 나타난다.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.12 no.3
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• pp.68-73
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• 1990

Fibrous dysplasia is an idiopathic skeletal disorder in which medullary bone is replaced and disturbed by poorly organized, structually unsound fibroosseous tissue, which may produce cortical expansion. When facial bones are involed, considerable esthetic deformity may result. The term monostotic fibrous dysplasia has been applied when one bone is involved : when more than one bone is affected, the term polyostotic used. The polyostotic form may be accomplished by pigmented skin lesion (Jaffe type), or by pigmented skin lesions with endocrine disturbance (Albright syndrome). No general agreement exists on the cause of fibrous dysplasia. A few authors have suggested that fibrous dysplasia arises as a resujlt of trauma. It occurs predominantly in infant, adolescent females and runs a variable clinical course. When several bones are involed, it tends to be unilateral. Involements of alveolar bone may produce displacement of teeth with malocclusion, or loss of teeth, or both. Radiographycally, it shows an indistinctly delimited osteolytic defect with a bubble - like pattern, but without a sclerotic rim. The preferred treatment is almost always surgery. If the lesion is extensive, surgical intervention with use of recontouring procedures aimed at the correction of esthetic or funtional disturbances is preferred treatment. Now, we present a case of fibrous dysplasia on the left maxilla and the zygoma treated by bony contourign via hemicoronal flap and intraoral approach with good results.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.27 no.4
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• pp.334-345
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• 2005

The purpose of this study was to compare the postoperative stability and relapse according to 2 different fixation methods after bilateral sagittal split ramus osteotomies in mandibular prognathic patients. Tweenty one patients with Class III dental and skeletal malocclusion who were treated with bilateral sagittal split ramus osteotomy were selected for this retrospective study. We classfied the patients into two groups according to the fixation methods of bony segments after osteotomies. Group W (n = 10) had the bone segments fixed with nonrigid wire and Group S (n = 11) had bicortical screws inserted in the gonial area through a transcutaneous approach. Cephalometric radiographs were taken preoperatively, immediate postoperatively and more than six months postoperatively in each patient. After tracing the cephalometric radiographs, various parameters were measured. Before surgery, both groups were balanced with respect to linear and angular measurements of craniofacial morphology. Mean posterior sagittal setback amounts of the mandibular symphysis was 8.6 mm in the wire group and 6.79 mm in the rigid group, Six months postoperatively, the wire group had 33.1% relapse of the mandibular symphysis and 22.8% in the rigid group relapse. Both groups experienced changes in the orientation and configuration of the mandible. It is thought that Rigid screw fixation is a more stable method than nonrigid wire fixation for maintaining mandibular setback after sagittal split ramus osteotomy.

• The korean journal of orthodontics
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• v.24 no.3 s.46
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• pp.535-546
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• 1994

The research work has been conducted in order to establish facts on posterior available space in patients with crowding. The relation between crowding and posterior available space was worked out through a cross sectinal study of fifty eight patients showing class I malocclusion. In addition, a longitudinal overlapping study was done by examing twenty patients who had their bicuspid extracted and forty nine patients who did not, at the orthodontic department of dental clinic affiliated in Chosun University. The patients had been examined for three years and eight months on a regular basis, and the study yielded the following conculusion. 1. There was a great difference in posterior available space between patients with serious crowding and those with slight crowding. The former marked 15.2mm of posterior available space and the latter 19.9mm. 2. Posterior crowding index was acquired by joint consideration of the diameter of posterior teeth and posterior available space, and manifested the highest relationship with crowding among measured items. 3. Patients who had their bicuspids extracted exhibited increase in posterior available space of 1.6mm/year and those who did not 1.8mm/year. 4. The absorption of anterior border of ramus turned out to be most deeply related with the increase of posterior available space. 5. Anterior border of ramus was absorbed at the average rate of 0.7mm/year during the period of observation. 6. The extraction of bicuspids had little influnce on the change in posterior available space.

• The korean journal of orthodontics
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• v.34 no.1 s.102
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• pp.13-21
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• 2004

Recently several techniques have been reported for the treatment of anterior open bite in adults characterized by molar intrusion with skeletal anchorage. In this study, five adult patients who had anterior open bite malocclusion were selected to undergo upper molar intrusion with midpalatal miniscrew to close the open bite. The aim of this study is (1) to validate true intrusion of molars in adults (2) to test the usefullness of midpalatal miniscrews as anchorage for intruding upper molars (3) to evaluate the skeletal and dental changes of open bite closure. The results are as follows. (1) All had true intrusion of the maxillary molars. Mean amount of molar intrusion was 3.4mm(range 1.5-5mm). (2) No movement of midpalatal miniscrew occurred during their use. (3) Open bite closure was achieved for all 5 patients. The mandible closed and B-point rotated anteriorly and upward. The mandibular plane angle and the occlusal plane angle decreased.

• The korean journal of orthodontics
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• v.24 no.3 s.46
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• pp.547-554
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• 1994

This study was carried out in order to find out the soft tissue profile changes associated with maxillary incisor retraction in Angle's class I malocclusion patients. For this study fifty two female adult patients (Maximum Retraction Group 23, Minimum Retraction Group 29) who received orthodontic treatment were chosen. Following conclusions were obtained by analysing the changes of soft tissue and hard tissue before and after treatment. 1. When considering the mean changes of soft tissue and hard tissue, UP, LIP, Ls, Li (p<0.001), Point B, Si (p<0.01), Point A, Ss (p<0.05) were significant posterior movement in Maximum Retraction Group and UIP (p<0.001), LIP, Ls, Li (p<0.01), Point B, Si (p<0.05) were significant posterior movement in Minimum Retraction Group. 2. When considering the correlations between hard tissue and soft tissue changes, greater correlations were found in Minimum Retraction Group between UIP and Ls (p<0.01), Point A and Ss, UIP and Li, Point B and Si (p<0.05) than Minimum Retraction Group. 3. Correlations (p<0.01) were found between upper incisor retraction and posterior movement of the upper and lower lip in Thin Lip-Thickness Group, whereas no significant correlations were found in Thick Lip-Thickness Group. 4. Mean changes of the soft tissue thickness subsequent to incisor retraction were increased (p<0.01) in upper lip (Ls-Ls'), whereas no changes were found in lower lip.