• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.47 no.5
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• pp.373-381
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• 2021

Objectives: In the present study, the effects of sagittal split ramus osteotomy (SSRO) combined with intraoral vertical ramus osteotomy (IVRO) for the treatment of asymmetric mandible in class III malocclusion patients were assessed and the postoperative stability of the mandibular condyle and the symptoms of temporomandibular joint disorder (TMD) evaluated. Materials and Methods: A total of 82 patients who underwent orthognathic surgery for the treatment of facial asymmetry or mandibular asymmetry at the Department of Oral and Maxillofacial Surgery, Dong-A University Hospital, from 2016 to 2021 were selected. The patients that underwent SSRO with IVRO were assigned to Group I (n=8) and patients that received bilateral SSRO (BSSRO) to Group II (n=10, simple random sampling). Preoperative and postoperative three-dimensional computed tomography (CT) axial images obtained for each group were superimposed. The condylar position changes and degree of rotation on the superimposed images were measured, and the changes in condyle based on the amount of chin movement for each surgical method were statistically analyzed. Results: Group I showed a greater amount of postoperative chin movement. For the amount of mediolateral condylar displacement on the deviated side, Groups I and II showed an average lateral displacement of 0.07 mm and 1.62 mm, respectively, and statistically significantly correlated with the amount of chin movement (P=0.004). Most of the TMD symptoms in Group I patients who underwent SSRO with IVRO showed improvement. Conclusion: When a large amount of mandibular rotation is required to match the menton to the midline of the face, IVRO on the deviated side is considered a technique to prevent condylar torque. In the present study, worsening of TMD symptoms did not occur after orthognathic surgery in any of the 18 patients.

• The korean journal of orthodontics
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• v.49 no.1
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• pp.32-40
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• 2019

Objective: Precise identification of landmarks on posteroanterior (PA) cephalograms is necessary when evaluating lateral problems such as facial asymmetry. The aim of the present study was to investigate whether the use of lateral (LA) cephalograms can reduce errors in landmark identification on PA cephalograms. Methods: Five examiners identified 16 landmarks (Cg, N, ANS, GT, Me, RO, Lo, FM, Z, Or, Zyg, Cd, NC, Ms, M, and Ag) on 32 PA cephalograms with and without LA cephalograms at the same time. The positions of the landmarks were recorded and saved in the horizontal and vertical direction. The mean errors and standard deviation of landmarks location according to the use of LA cephalograms were compared for each landmark. Results: Relatively small errors were found for ANS, Me, Ms, and Ag, while relatively large errors were found for N, GT, Z, Or, and Cd. No significant difference was found between the horizontal and vertical errors for Z and Or, while large vertical errors were found for N, GT, and Cd. The value of identification error was lower when the landmarks were identified using LA cephalograms. Statistically significant error reductions were found at N and Cd with LA cephalograms, especially in the vertical direction. Conclusions: The use of LA cephalograms during identification of landmarks on PA cephalograms could help reduce identification errors.

• Journal of The Korean Astronomical Society
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• v.44 no.1
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• pp.23-32
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• 2011

We present a deep CCD imaging in B and V bands which allows us to analyze the vertical structure of NGC 4631. We derive the scale heights of the thin and thick disks at a variety of positions along the major axis of the disk. The scale heights of the thin disk are nearly constant while those of the thick disk tend to increase with increasing galactocentric distance. The mean scale heights of the thin disk derived from B and V images are similar to each other (~ 450 pc). Instead, those of the thick disk show a strong east-west asymmetry which is caused by the diffuse stellar emission that is most prominent in the north west regions above the disk plane. The ratio of scale heights ($z_{thick}/z_{thin}$) is about 2.5 in the east side of the disk. However, this ratio is greater than 4 for the thick disk above the disk plane in the west side of the galaxy.

• The Magazine of the Society of Air-Conditioning and Refrigerating Engineers of Korea
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• v.16 no.5
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• pp.516-524
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• 1987

This paper presents experimental data of fluctuation characteristics of local void fraction of air-water two-phase flow which are associated with the flow pattern, annular gap size and radial location in vertical concentric annuli with coefficient of skewness and kurtosis. The annular gap widths are 13mm, 11mm, and 9mm for a 38m inner diameter as the lucite outer tube. A electrical conductivity probe was used to measure the local void fraction and traversed diametrically from inner wall to outer wall using radial increments of 2mm. It was shown that distribution of the coefficient of skewness and kurtosis, which is related that the one is the asymmetry and the other peakness of local void fraction distribution was influenced by flow pattern, annular gap size and radial location.

• The korean journal of orthodontics
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• v.43 no.3
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• pp.113-119
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• 2013

Objective: To compare three-dimensionally the midfacial hard- and soft-tissue asymmetries between the affected and the unaffected sides and determine the relationship between the hard tissue and the overlying soft tissue in patients with nonsyndromic complete unilateral cleft lip and palate (UCLP) by cone-beam computed tomography (CBCT) analysis. Methods: The maxillofacial regions of 26 adults (18 men, 8 women) with nonsyndromic UCLP were scanned by CBCT and reconstructed by three-dimensional dental imaging. The frontal-view midfacial analysis was based on a $3{\times}3$ grid of vertical and horizontal lines and their intersecting points. Two additional points were used for assessing the dentoalveolar area. Linear and surface measurements from three reference planes (Basion-perpendicular, midsagittal reference, and Frankfurt horizontal planes) to the intersecting points were used to evaluate the anteroposterior, transverse, and vertical asymmetries as well as convexity or concavity. Results: Anteroposteriorly, the soft tissue in the nasolabial and dentoalveolar regions was significantly thicker and positioned more anteriorly on the affected side than on the unaffected side (p < 0.05). The hard tissue in the dentoalveolar region was significantly retruded on the affected side compared with the unaffected side (p < 0.05). The other midfacial regions showed no significant differences. Conclusions: With the exception of the nasolabial and dentoalveolar regions, no distinctive midfacial hard- and soft-tissue asymmetries exist between the affected and the unaffected sides in patients with nonsyndromic UCLP.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.33 no.4
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• pp.337-345
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• 2011

Purpose: The purpose of this study was to define the relation of the degree of menton deviation and 3-D CT (computerized tomography) measurements of the glenoid fossa and the mandible, which are considered to have an influence on menton deviation. Methods: The CT images were obtained in 60 adults and these were transmitted to a computer and reconstructed using computer software. According to the degree of the menton deviation, which was measured on the posteroanterior cephalogram, the subjects were divided into the menton deviated group (30 adults) and the symmetry group (30 adults). A total of 11 measurements that might have an effect on menton deviation were determined and these were measured in the right and left sides using the function of 3-D measurement in the computer program. The 11 measurements consist of 6 measurements in the glenoid fossa (vertical position of the glenoid fossa and articular eminence, the sagittal position of the glenoid fossa and articular eminence, the depth of the glenoid fossa, and the anterior angle of the glenoid fossa), and 5 measurements in the mandible (ramus length, frontal ramal inclination, lateral ramal inclination, body length, body height). Results: The comparison of the differences between the menton deviated and symmetry groups and correlation analysis on the degree of menton deviation were carried out. The results of comparison of the right and the left difference between the menton deviated and symmetry groups showed that the vertical position and depth of the glenoid fossa were significantly increased in the menton deviated group. Conclusion: The results of the present study show that consideration of the shape and position of the glenoid fossa is necessary for making the diagnosis and administering proper treatment in facial asymmetry patients and especially growing patients.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.39 no.5
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• pp.31-40
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• 2002

We propose a novel ultra-short asymmetric vertical directional coupler switch (VDCS) with high extinction ratios larger than 30㏈ composed of switching operation induced section (SOIS), extinction ratio adjusted section (ERAS), and extinction ratio enhanced section (ERES). In this VDCSs, switching operation is achieved by changing the refractive index of one core in SOIS. The improvement of extinction ratios larger than 30㏈ for both cross and bar states is achieved by controlling the asymmetry of refractive indices between both cores in ERES. After propagating through ERAS with symmetry in the structure, different extinction ratios between cross and bar states at the end of SOIS are changed to the same value. For this reason, the optimum asymmetry of the refractive indices of cores to have the maximum extinction ratios and the lengths of ERES are the same for cross and bar states. Design guidelines to achieve high extinction ratios with large tolerances are presented.

• The Journal of Korean Academy of Prosthodontics
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• v.25 no.1
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• pp.269-279
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• 1987

The purpose of this study was to obtain basic data needed to clinical diagnosis and treatment by investigating the occlusal wear facets and those related factors. Sixty-six subjects, ranging from 24 to 26 years of age without symptoms of stomatognatic system, were selected from dental students in Chosun University. The area of occlusal wear facets was measured and twenty subjects were selected, and divided into two groups (Group I and Group II). The Group I had small facet areas, and the Group II had large facet areas. These two groups were investigated into right and left side wear facet areas, vertical overlaps, occlusion types of working side, masticatory muscle activities, and asymmetry of right and left side masticatory muscle function. The results were as follows: 1. The average wear facet areas of all subjects was $22.84{\pm}88.95mm^2$, and Group I and Group II were $96.12{\pm}32.00mm^2$ and $372.94{\pm}65.63mm^2$ respectively. 2. The right and left wear facet areas of Group I were $46.72{\pm}14.36mm^2$ and $49.40{\pm}21.46mm^2$ respectively. The right and left wear facet areas of Group II were $175.27{\pm}45.75mm^2$ and $185.69{\pm}45.37mm^2$ repsectively. 3. The vertical overlap of Group I and Group II was $3.88{\pm}0.81mm$ and $2.88{\pm}1.14mm $ respectively. 4. Most of the Group I had Canine protection occlusion (80%), and most of the Group II had Group function occlusion (80%). 5. The masticatory muscle activities at rest position, maximum bite, habitual chewing, right and left unilateral chewing were greater in Group II than in Group I, especially in the masseter muscle of working side at right and left unilateral chewing. (P<0.01). 6. The asymmetry of right and left wear facets and masticatory muscle activities were greater in Group II than in Group I. (P<0.01).

• The korean journal of orthodontics
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• v.33 no.3 s.98
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• pp.211-222
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• 2003

The purpose of this study was to determine whether there is an association between disk displacement of the Temporomandibular Joint (TMJ) and dentofacial asymmetry In orthodontic patients. The subjects consisted of 60 female orthodontic patients between the ages of 18 and 38 years (mean age 23.3 years) who had visited the Department of Orthodontics at Seoul National University Dental Hospital from January 2000 to April 2002. On the basis of magnetic resonance imaging (MRI) of their bilateral TMJs, the subjects were divided Into four groups'. bilateral normal group (twenty-one persons); disk displacement of right TMJ group (six persons); disk displacement of left TMJ group (nine persons); and disk displacement of both TMJs group (twenty-four persons) Postero-anterior (PA) cephalograms and diagnostic models which had been taken before orthodontic treatment were measured. In the linear measurements, a line connecting the right and left Latero-Orbitale (Lo) represented the horizontal reference line (H). The vertical reference line (V) was constructed as a line bisecting and running perpendicular to H. One-way analysis of variance (ANOVA) was used to test whether the mean values of measurements between groups were significantly different. In addition, Bonferronil's multiple comparison test was performed at a level of 0.05. The results were as follows; 1 In the diagnostic model analysis, the overjet, nght molar relationship, and left molar relationship were significantly different among the four groups. 2. In the PA cephalometric analysis, differences in the right and left vertical position of the lower first molar and Ag were significantly dissimilar among the four groups. 3. If the disk displacement of TMJ was present on one side, the ipsilateral ramus was shorter, resulting in asymmetry in the vertical position of Ag. This study indicated that dentofacial asymmetry might be related to the disk displacement of TMJ.

• The Journal of Korea CHUNA Manual Medicine
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• v.4 no.1
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• pp.1-16
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• 2003

Objectives : The purpose of this study is researching for possibility that Moire topography be applied in group school screening for scoliosis known school health problem, and find acceptable method of early detection and early treatment for scoliosis Methods : The authors practiced Moire topography for primary & middle school 1,895 students[male 976, female 919] in Jeonju, korea in 2001. After we distinguished students who had abnormal finding in Moire topography and then re-examined spinal X-ray analysis. The data was analysed and evaluated statistically Results : According to this research, the abnormal finding in Moire topography was 53.7% (1,018 students), and students needed X-ray re-examination were 11.2% (213 students). Students diagnosed scoliosis by X-ray re-examination were 1.8%. According to statistical analysis, interval between vertical base line of pelvis and vertical base line of neck, gap between left distance and right distance to the vertical base line of pelvis and difference of contour lines have strong correlations with deformity degree of the body surface examined by Moire. Conclusions : Following this research, throughout early detection for scoliosis by Moire topography could reduce exposure from scoliosis radiographs, and could detect trunk asymmetry that couldn't be found existing X-ray examination, so it made selecting students under observation who have bad posture possible.