• The korean journal of orthodontics
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• v.23 no.4 s.43
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• pp.543-564
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• 1993

A cephalometric study was undertaken to reveal significant differences of craniofacial morphology of operated congenital cleft lip and palate subjects and control subjects. The material for this study consisted of 73 subjects with operated congenital cleft lip and palate subjects(53 males, 20 females) and 110 control subjects (7 males, 34 females) ranging from 3 to 14 years old. Each group was divided into four age groups (3-5, 6-8, 9-11, 12-14 year) and analyzed by Cohen's method and Burstone's method. The following conclusions were obtained ; 1. In Wit's appraisal, there was no difference the cleft lip and palate subjects and the control subjects. 2. In the cleft lip and palate subjects, they had smaller and more retrusive maxilla than the control subjects in both sexes. 3. In the cleft lip and palate subjects, they had more retrusive mandible than the control subjects in both sexes. 4. In the cleft lip and palate subjects, they had more concave profile than the control subjects.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.19 no.9
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• pp.662-668
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• 2007

In this study, jet fans are installed with 4 cases in the straight long tunnel; inlet-side setup, middle-side setup, outlet-side setup, and dispersion setup. A bus is selected as fired car, of which fire size is 20MW. And fired car locates at 100m, 700m, 1500m position from tunnel inlet, respectively. FLUENT, commercial finite-volume code, is used to analyze the performance. The velocity profile, $CO_2$ concentration, temperature distribution are examined for analysis. Performance of smoke control is compared by the backlayering length. Consequently, inlet-side setup of jet fans is a little more efficient than other cases considering the fire occurrence frequency in tunnel.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.19 no.9
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• pp.669-678
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• 2007

In this study, the ventilation characteristics is investigated numerically of the longitudinal ventilation method in the curved long road tunnel. Numerical work has been conducted for the jet fan location by utilizing the commercial finite-volume code, FLUENT. Configuration of the tunnel is three-lane, 1600 m long, $120m^2$ in area, 3000 m curvature radius. The velocity profile, distribution of mono-dioxide carbon and flow rate of air are examined in the tunnel. Through the analysis, it is found that the difference of ventilation flow rate Is a little by the jet fan location, but tunnel outlet setup (CASEIII) of jet fans is the most efficient concerned with CO concentration.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.19 no.5
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• pp.386-393
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• 2007

This paper studies the ventilation characteristics according to the jet fan location at the long road tunnel using the CFD software 'FLUENT' which is based on the finite volume method. The tunnel model used in the analysis has a length of 1600m, a cross sectional area of $120m^3$, and is composed of 3 lanes and one way. The velocity profile, the distribution of CO concentration and the ventilation flow rate within the tunnel are analyzed, respectively. In the analysis, it is found that the dependence of the ventilation flow rate upon the jet fan location is small, but the CO concentration in the tunnel is at the lowest when the jet fans are installed near the tunnel outlet. An air stream right below the jet fan is almost inactive due to the strong stream injection near the jet fan. Thus, the pollution level below the jet fan must be higher than the other area.

• The korean journal of orthodontics
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• v.54 no.4
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• pp.210-228
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• 2024

Objective: Understanding the orofacial characteristics and growth patterns in children is essential for both orthodontics and research on children with orofacial abnormalities. However, a concise resource of normative data on the size and relative position of these structures in different populations is not available. Our objective was to aggregate normative data to assess the growth of the orofacial skeletal structures in children with a well-balanced face and normal occlusion. Methods: The MEDLINE, Embase, and Scopus databases were searched. Inclusion criteria included longitudinal and cross-sectional studies on cephalometric measurement of skeletal tissues and a study population ≤ 18 years with a well-balanced face and normal occlusion. Key study parameters were extracted, and knowledge was synthesized. A quality appraisal was performed using a 10-point scale. Results: The final selection comprised of 12 longitudinal and 33 cross-sectional studies, the quality of which ranged from good to excellent. Our results showed that from childhood to adulthood, the length of the cranial base increased significantly while the cranial base angle remained constant; both the maxilla and mandible moved forward and downward. The profile becomes straighter with age. Conclusions: Growth patterns in children with a well-balanced face and normal occlusion follow accepted theories of growth.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.23 no.1
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• pp.7-14
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• 2001

Purpose : The lateral cephalometric Korean norms of the skeletal and pharyngeal dimension were analyzed for the diagnosis of obstructive sleep apnea syndrome(OSAS). Materials and Methods : The lateral cephalometric radiographies were taken in male(n=53) and female(n=50), who had a normal profile, class I occlusion, normal ANB $(0{\sim}4^{\circ})$ and normal Wits $Appraisal(-4{\sim}0mm)$. The X-rays were traced by two oral and maxillofacial surgeons twice. The significant differences between male-female and examiners were tested. Results : The angle of mandibular line to Nasion-Sella line was $31.12^{\circ}/33.79^{\circ}$ (in male/in female, p=0.0018). The lower Gonion angle was $73.74^{\circ}/73.74^{\circ}(p=0.9978)$. The length of the soft palate was 36.93mm/34.35mm(p=0.0002). The pharyngeal airway space was 13.42mm/11.55mm at mandibular plane level(PAS(ML))(p=0.0025). The hyoid was placed inferiorly to mandibular plane 10.18mm/7.72mm(p=0.0051). The results from this study are to be used for the diagnosis of OSAS.

• The korean journal of orthodontics
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• v.23 no.4 s.43
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• pp.455-474
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• 1993

Degenerative joint disease(DJD) has hun known as one of the diseases which affect the middleor old-aged people. But as orthodontists are getting interested in the adult orthodontics, it is not rare for them to meet the open-bite patients with the TMJ DJD in their clinics. The purpose of this article is to investigate the cephalometric characteristics of the open-bite cases with TMJ DJD. Twelve TMJ DJD patients($15.1\~39.5$ years old) were selected from the patients who visited Department of Orthodontics, Seoul National University Hospital. Cephalograms were taken and means from 60 measurements were compared by t-test with those of the fifty four healthy adults($20.0\~26.7$ years old) who have normal occlusion and TMJ. In this study male and female are compared respectively, for in the normal samples 26 measurements showed significant differences between the male and the female. The results and conclusions axe as follows: 1 In DJD group, ANB and Angle of convexity decreased, which means the retruding of the mandible. The interincisal angle was smaller than that of the normal group. The means of the overbite were -2.1mm in male and -3.0mm in female, and the means of the overjet were 5.6mm in male and 6.7mm in female. The profile was similar to that of Angle's Class II div.1 open-bite. 2. SN-GoMe and FMA increased in DJD but SN-PP and FH-PP did not show any significant difference. In TMJ DJD open-bite cases, the bony structure lower than the palatal plane seemed to play an important role in developing open-bite. 3. In DJD group, PH-ArGo, SArGo and Y-sxis angle increased significantly, but genial angle showed no significant difference. The means of hか were 50.1mm in male and 40.2mm in female, which were significantly smaller than those of the normal(56.5mm in male, 50.9mm in female). These findings seemed to indicate the posterior rotation of mandible resulted from the shortening of the ramus height. 4. Anterior faical height(AFH), upper anterior facial height(UAFH) and lower anterior facial height (LAEH) of DJD showed no significant increase as compared with those of the noraml group. There was no significant difference in the ratio of upper anterior facial height to lower anterior facial height(UAFH/LAFH). But, lower posterior facial height(LPFH) was significantly smaller than that of the normal group. 5. It was thought that the peculiar profile of the TMJ DJD open-bite was resulted from the posterior rotation of mandible as the ramus became short following the degerative destruction of of the condylar head and neck.

• The korean journal of orthodontics
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• v.32 no.4 s.93
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• pp.241-255
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• 2002

This study was performed to evaluate horizontal and vertical characteristics according to lateral cephalometry of adult Korean skeletal Class II patients using a selected horizontal and vortical reference planes of Koreans. 60 males and 60 females consisting of freshman of Yonsei University from 1996 to 1997 and patients with history of orthognatic surgery at the Dental Hospital of Yonsei University with a skeletal Class II profile were chosen and compared with 70 males and 70 females with normal occlusion. The skeletal Class R group had the following conditions : 1. Profile composed of a retrognathic mandible or protrusive maxilla; 2. Class II molar and canine key; 3. ANB-greater than $4^{\circ}; 4$. Wits appraisal-greater than 1.0mm; Cephalometric analysis consisted of 22 skeletal, 25 soft tissue, 12 dental measurements. The results were as follows. 1. There was no considerable vortical measurement difference between the skeletal Class II malocclusion group and the normal occlusion group in skeletal analysis. But, some variations were found between the two groups in soft tissue analysis. 2. Mandibular length of the skeletal Class II malocclusion group was smaller than that of the normal occlusion group. Mandible was more posteriorly positioned in the Class II malocclusion group than in the normal occlusion group. 3. The length and antero-posterior position of the maxilla were not different between the Class II malocclusion and the normal occlusion group. 4. The antero-posterior position of the nose, upper lip and maxillary soft tissue, and nasolabial angle were not different between the two groups. 5. Mandibular soft tissue of the Class H malocclusion group was more posteriorly positioned than that of the normal. 6. The vertical measurements of the incisors(U1-HP, L1-HP) were bigger in the Class II malocclusion group than in the normal, but those of the molars(U6-HP, U6-MP) showed no significant difference between the two groups. 7 Classifying the skeletal Class II malocclusion group according to the antero-posterior position of both jaws, normally positioned maxilla and retruded mandible was 43.3%, both normally positioned maxilla and mandible 28.3%, both retruded maxilla and mandible 20.0%..