• The Journal of the Korean dental association
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• v.55 no.4
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• pp.296-302
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• 2017

The traditional orthognathic surgery treatment consists of three steps: preoperative orthodontic treatment, orthognathic surgery, and postoperative orthodontic treatment, and the average treatment period is usually two years. Also, patients with Class III malocclusion should spend more time getting their facial features worse during the decompensation process. However, most of the patients who want orthognathic surgery visit the chief complaints of appearance improvement, and resolve this address as soon as possible. The concept of $^{\circ}{\AE}$Surgery - First 'does not cause a facial imbalance caused by decompensation for the pre - operative correction period, and the patient can obtain an improved facial profile immediately after the operation. In addition, the correction period is shortened by Regional Acceleratory Phenomenon (RAP) after surgery. However, it is not applicable to all patients. Patients with severe crowding, severe curve of spee or reverse curve of spee, severe transverse discrepancy of the maxilla and mandibular arch, and severe incisal angles are less likely to apply the technique. Although it is not yet possible to apply this technique to all patients, it has many advantages over the conventional method. Especially, the patients' preference is increasing due to the rapid appearance improvement and the shortening of the total treatment period.

• The korean journal of orthodontics
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• v.27 no.4 s.63
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• pp.661-668
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• 1997

There is a variation in the range of normal occlusion, and we must fit our treatment to the needs of each patient. If the upper or lower incisors are congenital)y missing, malformed, or crowded, the extraction of the incisor has some advantages over the extraction of premolars and nonextractions. The advantages are 1)simple mechanics, 2)reduced treatment time, 3)less relapse tendency, and 4)fewer facial profile changes. In order to decide which incisor should be extracted, we must consider certain factors 1)discrepancies in anterior arch length, 2)anterior tooth ratio, 3)periodontal and tooth health condition, and 4)the relationship between the upper and lower midline. Diagnostic set-up can be helpful to plan the treatment and show us the post treatment result.

• The Korean Journal of Health Service Management
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• v.6 no.4
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• pp.27-36
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• 2012

This study was to identify oral health status, O'Leary index and OIDP for the preventive oral prophylaxis among adults who visited dental hospitals or clinics from 30th September in 2011 to 31th May in 2012. The results are as follows. In DMFT, female(8.79) was higher than male(7.65)(p<.05). Housewife(9.70) and agriculture fishery industry was higher than others(p<.01). In O'Leary index, male(47.41), over 50 years old and 200~300 million won were higher than others. but these results wasn't significantly different. The majority answer about discomfort feeling in OIDP was during meal(66.7), and period of discomfort was 1~2 time/month(29.6). The discomfort feeling in OIDP effected on meal(40.8)and teeth brushing(50.0). The difficulty in daily life were toothache(21.0), cold feeling(20.8), and crowding(19.3). In conclusion, the negative factor of oral health status didn't effect daily life. These findings are require of development of oral health management program which included the prevention of toothache and cold feeling.

• Journal of the Korean Society of Visualization
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• v.19 no.2
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• pp.26-31
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• 2021

The spanwise growth of turbulence structures in turbulent pipe flow was investigated using the direct numerical simulation data of Re_𝜏 = 544, 934 and 3008. Two-point correlations and pre-multiplied energy spectra of streamwise velocity fluctuations were examined along the spanwise direction. The arclength direction is defined as r𝛳, which is useful for an analogy with the spanwise direction for channels or boundary layers; here, r and 𝛳 are the radial distance from the core and the azimuthal angles, respectively. Both analyses showed that the arclength scales increased with increasing the wall-normal distance. It showed that the coherent structures were confined in the core region due to the crowding effect of a circular pipe geometry. The pipe flow simulation could describe a realistic geometrical flow along the azimuthal direction, unlike the simulations of turbulent channel or boundary layer flow using periodic boundary conditions along the spanwise direction. The present results provided the spanwise organization of energy-containing motions over a broad range of scales in turbulent pipe flow.

• Journal of Korean Biological Nursing Science
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• v.24 no.1
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• pp.46-57
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• 2022

Purpose: This study aimed to identify factors affecting the number of emergency department visits by caregivers of children with fever. Methods: Data were collected from 145 caregivers whose children aged six or less with two or more emergency department visits annually mainly because of fever. Collected data were analyzed with descriptive frequency analysis, independent t-test, Fisher exact, one-way ANOVA, Scheffé test, Dunnett T3, Pearson's correlation, and stepwise multiple regression using SPSS 25.0 software. Results: Regression analysis results revealed that among factors influencing the number of emergency department visits by caregivers of children with fever were state anxiety (β= .35, p= .009), self-efficacy (β= -.29, p= .029), and gestational age of the children (β= .17, p= .010). These variables had an explanatory power of 42.3% concerning the number of emergency department visits. Conclusion: Our findings revealed that caregivers' level of state anxiety and self-efficacy were major factors influencing the number of emergency department visits. It is expected that providing education concerning fever and emotional support for caregivers of children with fever can relieve their anxiety and enhance their self-efficacy levels, which in turn may reduce the number of unnecessary emergency department visits of children with fever and ultimately address the issue of over-crowding in emergency department.

• Pediatric Gastroenterology, Hepatology & Nutrition
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• v.4 no.2
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• pp.161-166
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• 2001

Purpose: Poor living conditions such as overcrowding and sharing a bed are reported to be significant risk factors for H. pylori infection throughout childhood. We investigated the prevalence of Helicobacter pylori infection in Korean athletes who are obliged to live together in training camps over six months a year. Methods: Blood sampling and surveying through questionnaire were performed on 440 regular high school students (228 boys and 212 girls) and 220 athletes (148 boys and 72 girls) of a physical education high school. We measured serum IgG Ab to H. pylori in order to compare the prevalence of H. pylori infection between normal adolescents and athletes. In addition, we conducted a nutritional analysis and questionnaire survey for socioeconomic status in order to compare other risk factors that might influence H. pylori infection between groups. Results: The prevalence (43.2%) of H. pylori infection in athletes was higher than that (22.7%) in the controls. No significant differences in the nutritional factors or socioeconomic status, such as Hollingshead index, type of house, and crowding index, were found between the groups. Multivariate analysis showed that crowding and the difference in school type were the significant predictors of H. pylori seropositivity after controlling for dietary and socioeconomic factors. Conclusion: Living together in training camps might be a significant risk factor for H. pylori infection in athletes.

• Journal of the korean academy of Pediatric Dentistry
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• v.35 no.2
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• pp.268-277
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• 2008

Authors evaluated 1171 patients at the department of Pediatric Dentistry in Kyoungpook National University Hospital through clinical records and radiographs. And the following features were studied ; age, sex distribution, number of mesiodens per patients, cause of discovery of mesiodens, location, status of eruption, shape and orientation of crown, complication, dental age of adjacent upper incisor tooth at the time of surgical extraction of mesiodens and the relationship between the resolution rate of complication after extraction of mesiodens and the dental age of adjacent upper incisor tooth, length of diastema, the eruption status of lateral incisor and the crowding status of premaxilla. The followings are the results : 1. The cause of discovery of mesiodens were as follows ; delayed eruption of the permanent incisors in 13.8%, midline diastema in 11.6%, radiographs taken for other reasons in 23.4% and for caries treatment in 15.1%. 2. Complication due to the presence of mesiodens did not occur in 36.8%, delayed eruption of adjacent teeth was observed in 16.1%, midline diastema in 34.4%, rotation in 8.8%, displacement in 2.4%, and crowding in 1.0% of all evaluated patients. 3. As for the dental age of adjacent upper incisor tooth at the time of surgical extraction of mesiodens, below 1/3 of total root length were observed in 3.5%, $1/3{\sim}1/2$ of total root length in 19.9%, $1/2{\sim}2/3$ of total root length in 54.7% and over 2/3 in 21.9% of all evaluated patients. 4. Resolution rate of delayed eruption after the extraction of mesiodens was significant higher in the group with the root length below 1/2. Resolution rate of midline diastema was significant higher in the group with diastema width below 3mm and with non-crowding of adjacent upper incisor teeth.

• Journal of the Institute of Electronics and Information Engineers
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• v.53 no.7
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• pp.11-16
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• 2016

Silicon carbide (SiC) has received significant attention over the past decade because of its high-voltage, high-frequency and high-thermal reliability in devices compared to silicon. Especially, a SiC Schottky barrier diode (SBD) is most often used in low-voltage switching and low on-resistance power applications. However, electric field crowding at the contact edge of SBDs induces early breakdown and limits their performance. To overcome this problem, several edge termination techniques have been proposed. This paper proposes an improvement in the breakdown voltage using a double-field-plate structure in SiC SBDs, and we design, simulate, fabricate, and characterize the proposed structure. The measurement results of the proposed structure, demonstrate that the breakdown voltage can be improved by 38% while maintaining its forward characteristics without any change in the size of the anode contact junction region.

• The korean journal of orthodontics
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• v.48 no.3
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• pp.153-162
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• 2018

Objective: The aim of this trial was to compare the alignment efficiency and intermaxillary arch dimension changes of nickel-titanium (NiTi) or copper-nickel-titanium (CuNiTi) round archwires with increasing diameters applied sequentially to the mandibular arch. Methods: The initial alignment phase of fixed orthodontic treatment with NiTi or CuNiTi round archwires was studied in a randomly allocated sample of 66 patients. The NiTi group comprised 26 women, 10 men, and the CuNiTi ($27^{\circ}C$) group comprised 20 women, 10 men. The eligibility criteria were as follows: anterior mandibular crowding of minimum 6 mm according to Little's Irregularity Index (LII), treatment requiring no extraction of premolars, 12 to 18 years of age, permanent dentition, skeletal and dental Class I malocclusion. The main outcome measure was the alignment of the mandibular anterior dentition; the secondary outcome measure was the change in mandibular dental arch dimensions during 12 weeks. Simple randomization (allocation ratio 1:1) was used in this single-blind study. LII and mandibular arch dimensions were measured on three-dimensional digital dental models at 2-week intervals. Results: No statistically significant difference was observed between NiTi and CuNiTi according to LII (p > 0.05). Intercanine and intermolar arch perimeters increased in the CuNiTi group (p < 0.001). Inter-first premolar width showed a statistically significant interaction in week ${\times}$ diameter ${\times}$ application (p < 0.05). Conclusions: The effects of NiTi and CuNiTi round archwires were similar in terms of their alignment efficiency. However, the intercanine and intermolar arch perimeters, and the inter-first premolar width changes differed between groups.

• Journal of Dental Rehabilitation and Applied Science
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• v.16 no.2
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• pp.93-104
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• 2000

Orthodontic treatment in conjunction with second-molar extraction has been a controversial issue among orthodontists over many decades. The aim of this study was to investigate the treatment effects of upper second molar extraction cases. The sample included 19 upper second molar extraction orthodontic cases(ten Angle's Class I's and nine Class II's, average age=13Y 6M) cared at Kyung-Hee University Department of Orthodontics. Lateral cephalometric radiographs were taken before and immediately after treatment. Seventy-nine points were digitized on each cephalogram and 38 cephalometric parameters were computed comprising 22 angular measurements, 13 linear measurements, and 3 facial proportions. The data obtained from each malocclusion group were analyzed by paired t-test. The statistical results disclosed that there was no significant change in skeletal pattern after treatment except for that accountable by growth while there was statistically significant change in dentoalveolar and soft tissue patterns. There were no significant changes in Bjork sum, posterior facial height /anterior facial height and lower anterior facial height /anterior facial height. No significant changes in anteroposterior position of maxilla and palatal plane were manifested. Although facial axis and lower facial height was slightly increased and the mandible was rotated backward and downward, there was no remarkable change in the mandibular plane. There were statistically significant changes in distal movement of upper first molar, molar key correction and overjet reduction while there was no change in the occlusal plane. The upper lip was slightly retracted simultaneously with slight increase in nasolabial angle. These results signify that distalization of upper dentition with the second molar extraction does change occlusal relationship without gross modifications in the craniofacial skeletal configurationson. Henceforth the second molar extracted would be recommended to treat severe anterior crowding and protrusion with minor skeletal discrepancy.