• Journal of the korean academy of Pediatric Dentistry
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• v.48 no.2
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• pp.140-150
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• 2021

A total of 580 patients, who visited and received an orthodontic diagnosis in the Department of Pediatric Dentistry, Seoul National University Dental Hospital from 2017 to 2019, were investigated in this study. The aim of this study was to evaluate skeletal patterns of pediatric orthodontic patients determined with lateral cephalometric analysis and to analyze the relationship between skeletal pattern and probable associated clinical features. Also, the modality of orthodontic treatment for each skeletal classification was investigated to aid in therapeutic decisions. Patients aged 7 year accounted for the largest age group; 54.2% of patients showed a skeletal class I pattern, 22.2% showed a skeletal class II pattern, and 23.6% showed a skeletal class III pattern. Bi-maxillary retrusion for skeletal class I, retruded mandible with normal positioning of the maxilla for skeletal class II, and retrusion of the maxilla with protrusion of the mandible for skeletal class III were the largest subgroups by skeletal pattern. Brachyfacial type accounted for 55.0% of patients, followed by 31.9% of mesofacial type and 13.1% of dolichofacial type. The prevalence of anterior crossbite in the study was 43.3%, higher than that in previous studies.

• The korean journal of orthodontics
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• v.37 no.4
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• pp.245-259
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• 2007

Improvements in jaw relationship through clockwise rotation of the mandible may be desirable in some Class III patients with short low facial height. The aim of this study was to examine the treatment effect of face mask for Class III malocclusion patients according to their low facial morphology. Methods: Class III patients in their pubertal growth period were divided into two groups (Group 1, high LFH; Group 2, low LFH) according to lower facial height (LFH) by Ricketts (norm, 47). treatment changes between groups after face mask treatment was compared not only for hard tissue but also for soft tissue. Results: There were no significant differences between the two groups for the skeletal and soft tissues of the maxilla. There were no significant differences between the two groups for the skeletal posterior movement of the mandible, but posterior movement of the mandibular soft tissues in group 2 was larger than group 1. There were no significant differences between the two groups for the vertical hard tissue proportion changes of the mandible, but the vertical soft tissue proportion changes of the mandible in group 2 was larger than group 1. There was a significant correlation between the sagittal hard tissue and soft tissue changes of the maxilla and mandible, but there was no significant difference in the vertical changes. Conclusion: The clockwise rotation of the mandible occurred from use of the face mask, and posterior movement of soft tissues of the mandible was higher in Cl III patients with low LFH than with high LFH.

• The korean journal of orthodontics
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• v.28 no.5 s.70
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• pp.839-853
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• 1998

The present study was performed to prove the relationship between CO-CR discrepancy and facial skeletal type. In this study, 242 subjects were randomly selected and devided into 9 groups(devided into class I, II, III by ANB and each one devided into dolicho-, brachy-, mesofacial skeleton by Ricketts' vertical index). Lateral cephalometric radiographs with the mandible in centric occlusion were taken and measured and CO and CR bites were registered on all subjects. Diagnostic casts were mounted on Panadent articulator using an estimated face-bow and centric relation bite registration. The amount and direction of CO-CR discrepancy present was recorded using a Condylar Position Indicator(CPI) and a centric occlusion wax bite registration. CPI measurements and cephalometric measurements were statistically analyzed. The finding of this study can be summerized as follows : 1. There is little correlation between right and left sides for magnitude or direction of CO-CR discrepancies. The correlation between the magnitude of CO-CR discrepancy of left A-P and right A-P is higher than that of left S-I and right S-I. 2. Correlation of Class II malocclusion group was higher than that of the other groups between the magnitude of CO-CR discrepancy of left CPI and right CPI. 3. There is no difference between the pattern of CO-CR discrepancy of 9 malocclusion groups. 4. There is very little, if any, correlation between Skeletofacial measurements and CO-CR discrepancy. 5. In Class II brachyfacial skeleton and Class III mesofacial skeleton there was Lateral cephalometric measurements by that we predict CPI measurements was detected. That was overbite, overjet, upper genial angle, lower genial angle, saddle angle, articular angle, convexity of point A, ANS-Me/Na-Me, PCBL/RH, Posterior FH/anterior FH.

• The korean journal of orthodontics
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• v.26 no.3
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• pp.247-254
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• 1996

This study was performed to evaluate the hyoid bone position and airway in skeletal class III malocclusion and to prove the correlation between airway, hyoid bone position and mandibular position. The sample, considered of 47 class III malocclusion patients for experimmtal group and 52 class I malocclusion students for control group. Twenty three linear and angular measurements about hyoid bone position, airway size, mandibular position were taken from the lateral cephalograms. The differences between skeletal class III malocclusion group and normal occlusion group were compared and the correlation were evaluated statistically. The results obtained were as follows, 1. There were significant difference in S-APH, A-APH, N-APH, LAH-PBR, AA-PNS, PNS-ad between class I and class III malocclusion groups. 2. The hyoid bone was more anteriorly positioned in class III malocclusion group than class I malocclusion group and skeletal airway size in class III malocclusion group was smaller than class I malocclusion group. 3. There were significant difference in several measurements especially vertical and angular measurements of hyoid bone position and airway size between male and female. Usually the measurements in male were larger than female. 4. There were no significant correlation between hyoid bone position and airway size also airway size, and didn't showe significant correlation with mandibular position, 5. S-APH showed negative correlation with Wits appraisal and A-APH, N-APH showed positive correlation with Wits appraisal. On the contrary vertical measurements of hyoid bone position showed positive correlation with lower facial height.

• The korean journal of orthodontics
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• v.26 no.5 s.58
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• pp.637-645
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• 1996

In non-growing Class III malocclusion, the critical aspects which determine the need of orthognatic surgery are the severity of skeletal discrepancy, incisor inclination, overbile and soft tissue profile. Two-jaw surgery is more effective in correcting severe sagittal, vertical, transverse skeletal discrepancies and facial asymmetry. And more esthetic and stable profile can be achieved by two-jaw surgery Some midfacial deficiency Patients can be treated by Pyramidal Le Fort II osteotomy to maintain infraorbital rim and malar complex and to advance nasomaxillary complex. Others who require advancement of infraorbital rim and malar complex can be treated by quadrangular Le Fort II osteotomy. On the following cases, patients who had represented midfacial deficiency and mandibular prognathism were treated with combined orthodontic-surgical therapy by Le Fort II osteotomy and BSSRO.

• Journal of the korean academy of Pediatric Dentistry
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• v.46 no.3
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• pp.247-254
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• 2019

This study aimed to investigate the correlation between maxillary canine's dental maturity and skeletal maturity of growing children. Cephalometric radiographs, hand-wrist radiographs and panoramic radiographs of 299 children aged 6 - 17 years were analyzed to measure the cervical vertebral maturation stages (CVMS), skeletal maturity indicators (SMI) and Demirjian index (DI). Spearman correlation test was used to analyze the correlation between dental maturity and skeletal maturity. There was significant positive correlation between the DI and CVMS in both boys and girls (p = 0.000). Similarly positive correlation was found between the DI and SMI (p = 0.000). The results of this study suggest that the dental maturity of maxillary canine can be used as auxiliary maturity indicator in growing children.

• Journal of the Korea Convergence Society
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• v.12 no.6
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• pp.259-266
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• 2021

This is a descriptive research was to find out fatigue, musculoskeletal pain and job satisfaction in rehabilitation centers employees. The research subject was 199 rehabilitation center employees, and the collected data were analyzed through descriptive statistics, t-test, ANOVA, Scheffé's test, Pearson's correlation coefficients and multiple regression. The results revealed that the significant predictors of job satisfaction for rehabilitation center employees were working duration(β=-.033, p=.010), fatigue(β=-.051, p=.015), and musculoskeletal pain(β=-.020, p=.047), explaining 8.4% of the variation in job satisfaction(F=5.549, p<.001). These results can be recommended as preliminary data for preventing and managing fatigue and musculoskeletal pain of rehabilitation centers employees who play an important role in the community.

• The Journal of the Convergence on Culture Technology
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• v.7 no.4
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• pp.163-170
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• 2021

The purpose of this study is to identify the harmful factors of teacher's job stress and occupational-related musculoskeletal diseases, and to investigate according to job types to seek solutions and improvement measures for removing harmful factors. A total of 168 elementary and high school teachers in Seoul were surveyed. As a result, the average RULA score of the teacher was 4.2 points, and the average RULA score of the teacher who did not complain of musculoskeletal diseases was 4.3 points. In addition, the average job stress score of the teacher was 58.9 points, and the stress score by factor was in the order of student guidance, work burden, loss of authority, organizational structure and curriculum, treatment and welfare, human relations. As a result of analyzing the teacher's RULA score and job stress, it was possible to derive a correlation between musculoskeletal disorders and job stress caused by occupation.

• Journal of the Korean Geographical Society
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• v.41 no.2 s.113
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• pp.188-194
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• 2006

Three-dimensional topological data is essential for 3D modeling and application such as emergency management and 3D network analysis. This paper reviewed current 3D topological data model and developed a method to construct 3D topological node-relation data structure from 2D computer aided design (CAD) data. The method needed two steps with medial axis-transformation and topological node-relation algorithms. Using a medial-axis transformation algorithm, the first step is to extract skeleton from wall data that was drawn polygon or double line in a CAD data. The second step is to build a topological node-relation structure by converting rooms to nodes and the relations between rooms to links. So, links represent adjacency and connectivity between nodes (rooms). As a result, with the conversion method 3D topological data for micro-level sub-unit of each building can be easily constructed from CAD data that are commonly used to design a building as a blueprint.

• Journal of dental hygiene science
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• v.9 no.5
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• pp.545-550
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• 2009

This study set out to examine the knowledge about and preventive actions against musculoskeletal diseases among dental hygiene students according to the Health Belief Model, suggest a need for programs to promote health and prevent those diseases, and investigate their relations, A survey was taken among 83 sophomores and 114 juniors at the dental hygiene major of a college in Gyeonggi Province. Analyzed by using SAS 8.0 version. The findings are as follows: 1. The sophomores and juniors scored $22.50{\pm}2.37$ and $22.29{\pm}3.01$ points, respectively, on susceptibility of the Health Belief Model with significant differences between the two groups(P < 0.01). Significant differences were also found between the sophomores that scored $18.82{\pm}2.60$ points and the juniors that scored $18.64{\pm}2.77$ points on benefit(P < 0.05). 2. The juniors experienced a higher level of pain than the sophomores with statistical significance observed on the neck, shoulder, lower back, knee, foot, and ankle(P < 0.05). 3. Of the Health Belief Model, severity had significant positive correlations with 'Placing frequently used tools near the dental technician' and 'Trying to avoid repeating the same task and diversify tasks'(P < 0.01). And benefit was positively correlated with 'Trying to reduce the frequency of bending and stretching out during treatment, 'Trying not to lean much with the neck, back, arm, and wrist' and 'Trying to maintain the torso in the neutral position'(P < 0.01). The results suggest that there should be some instructions to help dental hygiene students practice the preventive actions against musculoskeletal diseases and further prevention programs against those diseases.