• 대한치과교정학회지
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• 제20권1호
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• pp.123-133
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• 1990

The work was undertaken to evaluate the calcification of the second and the third molars in skeletal Class II and III malocclusions. The differences in the calcification stages between skeletal Class II and III malocclusion were evaluated and statistically analysed from panoramic radiographs of 202 males and females ranging in age from 11 to 15 years old. The results were as follows, 1. The calcification stages of the second and the third molars were not different between the skeletal Class II and III malocclusions in each age groups of both sexes. 2. The calcification stages of lower second and third molars of the skeletal Class III malocclusion are more advanced than those of the skeletal Class II malocclusion in male. 3. The clacification stages of upper second and third molars are more advanced than those of lower second and third molars in skeletal Class II malocclusion. 4. The calcification stages of lower second and third molars are more advanced than those of upper second and third molars in skeletal Class III malocclusion.

• 충청수학회지
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• 제26권1호
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• pp.167-174
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• 2013

The main goal in the present paper is to obtain a solution of Einstein's unified field equations for the third class in $X_4$.

• 치과방사선
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• 제22권1호
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• pp.149-160
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• 1992

The purpose of this study was to localize the inferior alveolar canals in relation to the root apices of the mandibular third molars, according to their positions and degrees of impaction using vertical tube shift technique. One hundred three mandibular third molars, from 95 persons consisted of 57 males and 38 females, were clinically and radiographically investigated. The mandibular third molars had no pericoronitis and periapical lesions, and showed an evidence of complete root formation. The obtained results were as follows: 1. In localiztion of the inferior alveolar canals in relation to the root apices of the mandibular third molars, the inferior alveolar canal was located at the buccal side of the root apices of mandibular third molar in 77.7%, below the root apices in 16.5%, and the lingual side of root apices in 5.8%. 2. The positions of the mandibular third molars according to the Winter's Classification were as follows; 36.9% in Class Ⅰ, 21.3% in Class Ⅱ, 14.7% in Class Ⅲ, 4.8% in Class Ⅳ, 1.9% in Class Ⅴ, 17.5% in Class Ⅵ, 2.9% in Class Ⅶ. In localization of the inferior alveolar canals in relation to the root apices of the mandibular third molars according to the Winter's Classification, 92.1 % of Class Ⅰ, 86.4% of Class Ⅱ, 80.0% of Class Ⅲ, and 100.0% of Class Ⅳ and Ⅴ were located at the buccal side. In Class Ⅵ, however, 33.3% was located at the buccal side, 44.5% below the root apices, and 22.2% at the lingual side. 3. The degree of impaction was revealed to be 53.4% in Degree Ⅰ, 36.9% in Degree Ⅱ, and 9.7% in Degree Ⅲ. In localization of the inferior alveolar canals in relation to the root apices of mandibular third molars according to degree of impaction, 98.2% of Degree Ⅰ was located at the buccal side. In Degree Ⅱ, 60.5% was located at the bucal side, 31.6% below the root apices, and 7.9% at the lingual side. In Degree Ⅲ, 30.0% was located at the buccal side, 40.0% below the root apices, and 30.0% at the lingual side.

• 대한치과교정학회지
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• 제9권1호
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• pp.117-123
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• 1979

The aspects examined in the present study concerning the location and position of the lower third molar and the interrelationships of this molar, the gonial angle, and the second lower molar in subjects aged 8-24 are based on measurements made from 472 orthopantomograms. The following conclusion were drawn on the basis of the present study. 1. The gonial angle decreased with age, but slight enlarging occurred in the age group 20-21. 2. The angulation of the third molar in relation to the second molar did not correlate with the size of the gonial angle but decreased with developmental stage. 3. The mesial angle between the longitudinal axis of the second molar and the mandibular base line correlated significantly with the gonial angle. The above angle were smaller in Class II, Divison 2 and larger in Class III than in Class I and Class II, Division 1. 4. The rate of presence of lower third molar was 74.4%.

• 한국초등과학교육학회지:초등과학교육
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• 제38권3호
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• pp.360-374
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• 2019

The purpose of this study is to investigate the self-perceptions of the elementary school students' on the affective, behavioral and cognitive domains in science class. To see if there are differences in students' perceptions according to grade levels, a self-perception questionnaire was applied to third and fifth grade students in Seoul, Korea. The major results of the study are as follows. First, the perception level of the affective domain was higher than that of the cognitive domain in third grade students. There was no significant difference in the self-perception level of the fifth grade students. Both third and fifth grade students perceived the greatest improvement in the cognitive domain through one year of science teaching. Second, in the life science class, the same tendency was also observed. The students in the third and fifth grade reported that cognitive domains were the most improved through the one-year life science class. Third, when the students' perceptions were compared by grades, the third grade students showed higher self-perception scores than fifth grade students. As the grade increased, the perception scores of the students' lowered. Based on these findings, implications for science education research and teaching and learning at school are discussed.

• 대한소아치과학회지
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• 제35권2호
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• pp.235-242
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• 2008

본 연구는 I급 부정교합과 III급 부정교합 어린이의 수완부 골성숙 단계와 하악 제3대구치 발육을 비교.평가하고자 하였다. 이를 위해 전남대학교병원 소아치과에 내원한 환자들로 8세부터 15세 사이의 Angle I급 부정교합을 지닌 남자 149명, 여자 155명 그리고 Angle III급 부정교합을 지닌 남자 153명, 여자 155명, 총 612명을 대상으로 하였으며 골성숙 단계 평가를 위해 수완부 사진을 이용한 Fishman의 방법을 사용하였고 하악 제3대구치의 발육 단계를 평가하기 위해 Orthopantomogram을 이용한 Gat 등의 New Six-Developmental-Stage 방법으로 판독하여 다음과 같은 결과를 얻었다. 1. 골성숙 단계는 I급 부정교합과 III급 부정교합군 모두 전반적으로 여자가 남자보다 빠르나(p<0.05) 하악 제3대구치의 석회화 단계는 성별 차이가 없었다. 2. 남녀별 골성숙 단계와 하악 제3대구치의 석회화 단계는 I급과 III급 부정교합군 간에서 유의한 차이가 없었다. 3. I급 부정교합과 Ⅲ급 부정교합군의 수완부 골성숙 단계와 하악 제3대구치 석회화 단계 사이의 상관관계는 두 군모두 높은 상관성을 보였다(p<0.01). 4. I급 부정교합과 III급 부정교합군의 하악 제3대구치 석회화 단계와 연령사이의 상관관계는 두 군 모두 높은 상관성을 보였다(p<0.01). 이상의 결과로 수완부 골성숙도와 하악 제3대구치 발육은 I급 부정교합과 III급 부정교합군 간에 차이가 없었다.

• 대한치과교정학회지
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• 제24권3호
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• pp.695-707
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• 1994

This study investigates the effects of third molar on the occlusal plane in Angle's class El malocclusion with possibilities of posterior crowding and the interrelationships of occlusal plane inclinations to other skeletal patterns. Above investigations might showed that considerations should be given to third molars with possibilities of posterior crowding in establishing diagnosis and treatment plans for Angle's class III malocclusion patients. The following conclusions were obtained 1. In events of third molars causing possible posterior crowding, maxillary third molars showed more mesial inclinations than second molars, and compared to those with third molar missing cases, first molars were more mesially inclined and displaced more inferiorly from the palatal plane and OP-MP was increase , thus the occlusal plane was less steep. 2. In events of third molars causing possible posterior crowding, the anglulation between AB line and mandibular plane was decreased and ANB showed negative values. Thus chin points were more protruded, ramus were more anteriorly displaced, and increase in lower facial height, genial angle, effective mandibular length and mandibular plane angle were observed. This in all caused more vertical opening and more severe skeletal disturbance. 3. OP-MP was increased as the maxillary first molars were more inferiorly displaced from the palatal plane. As this angle was increased mandibular planes were more inferiorly inclined and LFH, genial angle, effective mandibular length were more increased and mandibular ramus was more anteriorly placed. 4. As the maxillary first molars were more inferiorly placed from the palatal plane, more increased OP-MP/PP-MP ratio made the occlusal plane less steep. As OP-MP/PP-MP was increased, mandibular ramus was more anteriorly placed and made longer, and facial angle and effective mandibular length were increased.

• 수산해양교육연구
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• 제29권1호
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• pp.209-223
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• 2017

The purpose of this study is to compare and analyze science self-efficacy, science self-concept and scientific attitude according to the class size in the elementary school. For this purpose, three research questions were set as follows; First, are there any differences in science self-efficacy according to the class size? Second, are there any differences in science self-concept according to the class size? Third, are there any differences scientific attitude according to the class size? To solve this research questions, the subjects in this study were 809 5th and 6th grade students of eight elementary schools in Busan. 220 were sampled from small-size classes, 354 from mid-size classes and 235 from large-size classes. The results of this study through the process are as follows; First, there were significant differences in science self-efficacy according to the class size. Second, there were significant differences in science self-concept according to the class size. Third, according to the result, there was not a significant difference in scientific attitude according to the class size. The findings of the study suggest that it is necessary the class size should be adjusted to the appropriate level for improving student's science self-efficacy and science self-concept.

• Imaging Science in Dentistry
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• 제52권1호
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• pp.19-25
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• 2022

Purpose: This study evaluated the distance from the posterior root apices to the maxillary sinus floor (MSF) and the frequency of roots touching or protruding through the MSF using cone-beam computed tomography (CBCT). Materials and Methods: This study included 100 subjects divided into different vertical and anteroposterior skeletal growth patterns. On CBCT images, the distance from the posterior root apices to MSF was measured and the frequency of roots touching or protruding through the MSF was evaluated using NNT software (version 5.3.0.0; ImageWorks, Elmsford, NY, USA). Results: No statistically significant differences were found in the distance from the posterior root apices to the MSF among vertical skeletal groups (P>0.05). The palatal roots of the first molar and the palatal, mesio-buccal and disto-buccal roots of the second molars had significantly less distance from MSF in skeletal class II than in class III (P<0.05). The high-angle group had the highest frequencies of roots touching or protruding into the maxillary sinus (49.8%); the lowest proportion of these roots was found in skeletal class III (28.3%) and the highest proportion in class II (50.3%). Males had shorter distances from the posterior root apices to the MSF and higher frequencies of roots protruding through or touching the MSF than females. Conclusion: Anteroposterior skeletal growth patterns and sex affected the distances from the maxillary posterior roots to the MSF. The frequency of roots protruding into or touching the sinus was affected by both vertical and anteroposterior skeletal groups and sex. These findings have implications for dental practice.

• 과학교육연구지
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• 제42권3호
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• pp.352-370
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• 2018

이 연구의 목적은 Peer Instruction의 지속적 활용이 초등학교 3학년 학생들의 과학 수업참여도와 토론 능력의 신장에 어떤 영향을 미치는지 살펴보고자 이루어졌다. 수업 주제와 관련된 선다형 문항을 활용하여 이루어지는 토론식 수업인 Peer Instruction이 3학년 과학 교과의 전차시의 수업에 대하여 6개월 동안 지속적으로 적용이 이루어졌고, 과학 수업참여도와 토론 능력을 조사하여 그 신장 정도를 알아보았다. 그 결과, 수업참여도 5개 영역인 수업준비하기, 수업활동하기, 의사표현하기, 수업확장하기, 수업열정, 모두에 대하여 통계적으로 유의한 효과를 나타내었음은 물론, 토론 능력 6개 영역인 논리력, 분석력, 듣기능력, 수용성, 규칙성, 적극성 영역에 대해서도 통계적으로 모두 유의한 효과를 보이는 것으로 나타나, Peer Instruction의 적용은 초등학교 3학년 학생들의 수업참여도와 토론 능력의 변화에 매우 긍정적인 영향을 미치는 것으로 확인되었다.