• The korean journal of orthodontics
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• v.18 no.1 s.25
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• pp.217-225
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• 1988

This study was undertaken to examine relationship between tooth size and arch dimension in dental crowding. Two groups of dental casts were selected on the basis of dental crowding. One group, consisting of 51 pairs of dental casts (24 male and 27 female), exhibited remarkable dental crowding. A second group, consisting of 60 pairs of dental casts (30 male and 30 female), exhibited little or no crowding. Mean and standard deviation of the following parameters were used to compare two groups. individual and collective mesiodistal tooth diameters, buccal and lingual arch widths and arch area. The following results were obtained. 1. The crowed group revealed larger tooth size than noncrowded group. (p < 0.01) 2. The crowded group smaller maxillary dental arch dimension than noncrowded group except lingual arch width at canine region. (p < 0.01) 3. The corwded group revealed smaller mandibular dental arch dimension than noncrowded group except lingal arch width at second premalar region in the male and buccal arch width at canine, premolar region in the female. (p < 0.01) 4. The crowded group revealed smaller arch area than noncrowded group in the female (p < 0.01), but there was no significance in the male.

• The korean journal of orthodontics
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• v.47 no.3
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• pp.176-185
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• 2017

Objective: To evaluate the relationship of gingival thickness (GT) and the width of keratinized gingiva (WKG) with different malocclusion groups and the level of crowding. Methods: A total of 187 periodontally healthy subjects (121 females and 66 males) who presented at the Faculty of Dentistry in $Y{\ddot{u}}z{\ddot{u}}nc{\ddot{u}}$ Yil University for orthodontic treatment were enrolled in the study. The individuals involved in the study were divided into three groups; Angle Class I malocclusion, Angle Class II malocclusion, and Angle Class III malocclusion. Each group was classified as mild, moderate, or severe according to the level of crowding. WKG was determined as the distance between the mucogingival junction and the free gingival margin. GT was determined by the transgingival probing technique. Factorial variance analysis and the Duncan multiple comparison test were employed to identify the extent to which a difference was apparent between the groups according to these parameters. Results: It was determined that teeth in the mandibular anterior region display the thin gingival biotype. WKG and GT were observed as being higher at the mandibular incisor teeth in the severe crowding group and at the mandibular canine teeth in the mild crowding group. The GT of the mandibular right central and lateral incisors was found to be thinner in the Angle Class III group. Conclusions: Within the limits of this study, the results demonstrate that, there is no significant relationship of WKG and the mean GT in the mandibular anterior region according to the Angle classification.

• The korean journal of orthodontics
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• v.51 no.2
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• pp.86-94
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• 2021

Objective: This study aimed to investigate the effect of micro-osteoperforations (MOPs) on external apical root resorption (EARR) during the initial orthodontic alignment phase of maxillary anterior crowding. Methods: Thirty patients (25 females, 5 males; mean age, 22.66 ± 3.27 years) who presented with moderate crowding of the upper labial segment and underwent extraction-based fixed appliance treatment were recruited. They were randomly allocated to receive adjunctive therapy with MOPs (n = 15) or treatment with fixed appliances only (control group; n = 15). EARR was measured from long-cone periapical radiographs taken at the start and the sixth month of treatment. A correction factor for the enlargement difference was used to calculate EARR. Data were analyzed with descriptive statistics and repeated-measures analysis of variance. Results: The mean root lengths of 168 teeth were measured and showed no statistically significant difference (p > 0.05) after six months of fixed appliance treatment in the MOP (mean difference [MD] = 0.13 mm; 95% confidence interval [CI] = -0.10-0.35) and control group (MD = 0.14 mm; 95% CI = -0.10-0.37). Most of the roots in the MOP and control groups (42.86% and 52.38%, respectively) showed only mild resorption. Less than 8% of the roots in both groups (7.14% in the MOP group and 4.76% in the control group) showed moderate resorption. Conclusions: Acceleration of orthodontic tooth movement with adjunctive MOPs therapy during the alignment phase does not exacerbate EARR in patients with moderate crowding of the upper labial segment in comparison with controls.

• Journal of the Korean Institute of Landscape Architecture
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• v.30 no.6
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• pp.79-97
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• 2003

The purpose of this paper is to analyze a causal model determining social carrying capacity(SCC) in natural parks, to answer the research question: What is the mechanism for determining SCC in natural parks (NP)\ulcorner After reviewing the literature on SCC and recreation activities in Korean natural parks, we constructed a conceptual framework and formulated the hypothesis of this research. We obtained data through a questionnaire which surveyed 487 visitors at 6 of the 73 NP in Korea during 2001, based on a stratified sampling method. We analyzed the data using descriptive statistical methods, the mean difference test, Pearson's correlation analysis, and path analysis method. We found that 1) The direct effect of resources, activity space(AS), visitor's expectation(VE), encounter, crowding, damage of resources(DR), maintenance condition of resources and facility(MCRF) to SCC are 3.45, 3.62, 2.75, 2.72, 1.32, and 4.77 times more important than that of crowding, respectively, while the indirect effect of resources, AS, VE, encounter, and DR to SCC is 13.03, 11.19, 3.34, 1.3, 2.05, 1.10, 0.05 and 2.30 times more important then that of crowding, respectively, 2) Causal effects of resources, facility, AS, VE, number of visitors(NV), encounter, crowding, VM, DR, and MCRF to SCC turned out to have 0.3523, 0.3321, 0.1751, 0.1465, 0.0307, 0.0762, 0.0604, -0.0510, -0.1177 and 0.2165, respectively, and 3) The causal effect of activity base(AB) and activity atmosphere(AA) to SCC turned out to have 2.57 and 1.1 times higher than that of MCRF, respectively. The research results suggest that 1) this conceptual framework is highly useful for the development of substantive theory and methodology; 2) management issues of AA and MCRF turned out to have 0.81 times in SCC that of AB, i.e, SCC can be significantly improved from control of AA and MCRF; and 3) supply of excellent resources and convenient facilities is needed to increase social carrying capacity. It is recommended that more empirical studies be performed in the future according to the season, visitor characteristics, and AS by NP.

• The korean journal of orthodontics
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• v.25 no.5 s.52
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• pp.593-604
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• 1995

Mandibular incisor crowding is one of the most common features of malocclusion and is interesting characteristic in view of relapse and stability after orthodontic treatment. There are many potential factors in the etiology of lower anterior crowding. The tooth size variation is one of them, but biologic significance for the faciolingual width of the teeth has been overlooked. Peck and Peck reported that persons with ideal mandibular incisor alignment were shown to have incisor with smaller mesiodistal and larger faciolingual dimensions than persons with incisor crowding. On the basis of these findings they suggested MD/FL index as a clinical guideline for the assessment for lower incisor crowding. The present study was undertaken to examine the relationship between mandibular incisor crowding and mandibular incisor dimension, and determine their correlation with arch length discrepancy. 154 dental casts of people from 11 to 17 years of age were made, and were divided into normal group with irregularity index less than of 1, and crowding group with irregularity index greater than 1.The casts were measured and analyzed statistically. The results were as follows. 1. The mean mesiodistal width for mandibular incisor was larger in crowding group, and has significant difference in central inciosr measurement. There are no significant differences in the faciolingul width and MD/FL index. 2. Irregularity index has significant correlation coefficients with mesiodistal width and MD/FL index for mandibular incisor in crowding group, but no correlation with faciolingual width. It also has correlation with maxillary and mandibular arch length discrepancy, total tooth material, mandibular intercanine width, and mandibular inter first premolar width. 3. Upper and lower arch length discrepancy have significant correlation with mesiodistal width of mandibular incisor and overbite, but have no correlation with faciolingual width. Lower arch lenth discrepancy has significant correlation with MD/FL index for mandibular incisor and upper arch length discrepancy has correlation with MD/FL index for mandibular lateral incisor. 4. Significant differences were observed between normal and crowding group for the mandibular arch length discrepancy and overbite.

• Journal of Life Science
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• v.29 no.7
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• pp.762-768
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• 2019

Doellingeria scabra Thunb. (syn. Aster scaber Thunb.), a perennial herb in the family Asteraceae, is frequently found in the wild mountain regions of Korea. This aim of this work was to measure the characteristics of patchiness of D. scabra in a local population on Mt. Maebong in Taeback-ci, Gangwon-do. The spatial distribution pattern of this species was estimated by analyzing ecological data by methods including the index of dispersion, Lloyd's mean crowding, and Morisita's index. The mean population density of the D. scabra population was 2.94. The D. scabra individuals were uniformly or randomly distributed in small-scale plots and were aggregately distributed in two large-scale plots ($16{\times}32m^2$ and $32{\times}32m^2$). The mean crowding ($M^*$) was 0.916. The mean patchiness index (PAI) was 0.796. Morisita's coefficient tended to decrease the density of the population as the plot size increased. The expected value of Eberhardt's index ($I_E$) in the local population was 2.623. Moran's I of D. scabra significantly differed from the expected value in 6 of 8 cases (75.0%). The first five classes were positive, with four showing statistical significance, indicating similarity among individuals in the first four distance classes (I-IV, 8 m), The results presented here could provide a theoretical basis for the conservation of D. scabra (Korean: chamchwi) and for the rehabilitation and sustainable management of forest ecosystems on Mt. Maebong, as well as on other mountains.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.30 no.6
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• pp.516-525
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• 2004

Mandibular symphyseal distraction osteogenesis is an alternative approach for correcting mandibular transverse deficiencies and dental crowding. The traditional approaches for these are extraction of teeth and arch expansion with traditional orthodontic treatment. Also extractions are usually unavoidable in patients with severe crowding. The purpose of this study is to evaluate the effect of mandibular symphyseal distraction osteogenesis by use of tooth-borne expansion appliance. All of 12 patients had been performed distraction osteogenesis. The surgical procedures were accomplished under local anesthesia and intravenous sedation in an ambulatory surgical setting using a routine distraction protocol. The latency period was 5 days or 7 days after symphyseal osteotomies. The rate & rhyth is a intermittent, 0.75mm or 1.0 mm per day and stabilized for 6, 8 weeks after distraction. The time of orthodontic tooth movement after distraction was variable from 2 weeks to 8 weeks (mean 3 weeks). All patients had been evaluated with study casts, plain periapical films, panorama radiograms before & after surgery. Mandibular symphyseal distraction osteogenesis increased mandibular arch width and corrected dental crowding, with paralleling tooth-borne movement, without proclination of the mandibular incisors.

• The korean journal of orthodontics
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• v.17 no.2
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• pp.289-297
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• 1987

For the comparisons of dental archs and crowdings between musical wind instrument players groups and non-wind instrument players groups, 64 male wind instrument players and 31 non-wind instrument players group were selected. The results of the measurements were as follow. 1 Upper intercanine widths, upper basal arch widths, lower basal arch widths were statistically significant between musical wind instrument players groups (Class A, Class B) and non-wind musical instrument players group. 2 The mean value of upper intercanine width m Class A ($373{\pm}2.3mm$) was greater than than in Class B ($362{\pm}17mm$) and non-wind musical instrument players group($360{\pm}16mm$) 3 The mean value of lower basal arch width m Class B ($422{\pm}25mm$) was greater than that in non wind instrument players group ($395{\pm}28mm$). 4 The differences in the mean values of crowdings between Class A and Class Band non-wind instrument players group were not statistically significant.

• Journal of the Korean Institute of Landscape Architecture
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• v.30 no.1
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• pp.29-43
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• 2002

The purpose of this paper is to examine atmospherical factors affecting user's satisfaction in natural park to answer the research question: what are the effects of atmosphere on user's satisfaction in natural parks(NP). After reviewing the literature, mechanism of NP, and use elements in NP, We constructed the conceptual framework and have formulated the hypothesis of this research. We had obtained data through a questionnaire, which surveyed 508 visitors at 6 of the 73 NP in Korea in 2001, based on stratified sampling method. We have analyzed the data using descriptive statistical methods, the mean difference test, Pearson's correlation analysis, and the multiple linear regression method. We found that 1) the five atmospheric variables, j.e., number of users(NOU), crowding, damage to park resources(DPR), and maintenance of park resources and facilities(MPRF), encounter level(EL) affecting user's satisfaction, have tuned out to be statistically significant at a five percent level. The direction of the relationship between user's satisfaction and MPRF, NOU, EL is the same as that of the dependent variable and the opposite of crowding, and BPR, 2) in bivariate analysis, the positive relationships between user's satisfaction and park resources, MPRF are fairly high and statistically significant. The higher the value of DPR, and crowing, the lower the degree of user's satisfaction, 3) in multivariate analysis, such variables as NOU, crowding, DPR, EL, and MPRF affecting user's satisfaction have been statistically significant at five percent level, and 4) the relative contribution of MPRF, park resources, park facilities, NOU, crowding, DPR, and size of activity space on user's satisfaction have been determined to have respectively 6.00, 4.78, 2.53, 1.83, 1.64, 1.59 and 2.03 times more important than that of EL. Among the atmospheric variables, MPRF is the most important at 1.26 times higher than that of park resources. The research results suggest that the development of devices for the increase in user's satisfaction and user management program based on the knowledge we have found, be recommended in the planning and development process of natural park. The approach adopted by this research is valid and useful for evaluation criteria of NP. It is recommended that more empirical studies by activity types, activity spaces, and seasons on atmospheric elements affecting user's satisfaction be performed in the future.

• The korean journal of orthodontics
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• v.52 no.1
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• pp.66-74
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• 2022

Objective: To investigate demographic and skeletodental characteristics of one-jaw (1J-OGS) and two-jaw orthognathic surgery (2J-OGS) in patients with skeletal Class III malocclusion. Methods: 750 skeletal Class III patients who underwent OGS at 10 university hospitals in Korea between 2015 and 2019 were investigated; after dividing them into the 1J-OGS (n = 186) and 2J-OGS groups (n = 564), demographic and skeletodental characteristics were statistically analyzed. Results: 2J-OGS was more frequently performed than 1J-OGS (75.2 vs. 24.8%), despite regional differences (capital area vs. provinces, 86.6 vs. 30.7%, p < 0.001). Males outnumbered females, and their mean operation age was older in both groups. Regarding dental patterns, the most frequent maxillary arch length discrepancy (ALD) was crowding in the 1J-OGS group (52.7%, p < 0.001) and spacing in the 2J-OGS group (40.4%, p < 0.001). However, the distribution of skeletal pattern was not significantly different between the two groups (all p > 0.05). The most prevalent skeletal patterns in both groups were hyper-divergent pattern (50.0 and 54.4%, respectively) and left-side chin point deviation (both 49.5%). Maxillary spacing (odds ratio [OR], 3.645; p < 0.001) increased the probability of 2J-OGS, while maxillary crowding (OR, 0.672; p < 0.05) and normo-divergent pattern (OR, 0.615; p < 0.05) decreased the probability of 2J-OGS. Conclusions: In both groups, males outnumbered females, and their mean operation age was older. The most frequent ALD was crowding in the 1J-OGS group, and spacing in the 2J-OGS group, while skeletal characteristics were not significantly different between the two groups.