• 한국치위생학회지
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• 제23권1호
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• pp.83-89
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• 2023

Objectives: This study aimed to examine the relationship between COVID-19-related depressive symptoms and oral health among Korean adolescents. Methods: Data from the 17th Korea Youth Risk Behavior Web-based Survey were used and analyzed by the chi-squared test, and multiple logistic regression analysis was performed using SPSS 21.0. The final study population comprised 54,835 individuals. Results: The rates of toothache, gingival bleeding, tooth fracture, and tooth sensitivity were 21.2, 19.1, 8.7, and 30.6%, respectively. The rates of equal, increased, and decreased COVID-19-related depressive symptoms were 53.4, 36.9, and 9.7%, respectively. The rates of toothache, gingival bleeding, and tooth sensitivity were significantly higher (49.0, 48.3, and 46.3%, respectively) in the increased depressive symptom group than that in the decreased depressive symptom group (7.7, 8.1, and 7.7%, respectively). After adjusting for gender, school grade, school record, household economic status, tooth brushing frequency, smoking habit, and alcohol consumption, the risks of toothache, gingival bleeding, and tooth sensitivity in the increased depressive symptom group were symptom group were 1.64 (95% CI: 1.51-1.78), 1.55 (95% CI: 1.43-1.68), and 1.77 (95% CI: 1.65-1.89), respectively. Conclusions: There was a significant increase in oral symptoms in the group with increased depressive symptoms.

• 대한소아치과학회지
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• 제43권2호
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• pp.192-199
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• 2016

유치열에서 드물게 관찰되는 삼중치는 세 치아의 비정상적인 융합으로 나타난다. 몇몇 문헌들에서 이중치에 대해 보고하고 있지만, 삼중치에 대한 보고는 매우 드물다. 이러한 다중치는 유치열에서 더 흔하게 관찰되며, 몇 가지 임상적 문제점을 나타낸다. 심미적인 문제 뿐만 아니라 치아 우식증 및 파절에 취약함, 영구 치배의 결손, 교정적, 치주적 문제를 야기할 수 있으며, 복잡한 치아 구조로 인해 치수 치료를 어렵게 한다. 첫 번째 증례는 만 1세 7개월 남아의 상악 유전치부에 나타난 삼중치로, 깊은 우식으로 치수 치료가 필요할 것으로 예상되었고, Mineral Trioxide Aggregate (MTA)를 이용하여 부분 치수 절단술을 시행하였다. 두 번째 증례는 만 1세 9개월 남아의 하악 유전치부에 나타난 삼중치로 파절을 주소로 내원하였다. 파절편 조각을 제거한 뒤, 잔존 치아에서 치수 절제술을 시행하였다. 각각 24개월, 6개월간의 정기 검진시까지 특별한 합병증은 나타나지 않았으며, 수복물 또한 비교적 양호하게 유지되었다.

• 치위생과학회지
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• 제22권3호
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• pp.180-190
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• 2022

Background: Like direct infection from COVID-19, psychological concern about infection could affect health. Concern about COVID-19 infection was associated with individual habits to practice rules for preventing infection. Therefore, this study aimed to check occupational types and whether to practice tooth brushing after lunch depending on the occupation of economic workers and find correlations between concerns about infection due to COVID-19 pandemic and tooth brushing after lunch. Methods: The raw data was from the community health survey conducted in 2020. Among 229,269 adult participants aged 19 years and older, 138,970 economic workers were included in the final analysis. The chi-squared test was used to find differences in psychological concerns due to the COVID-19 pandemic. According to the participants, the rate of practicing tooth brushing after lunch was based on COVID-19-related psychological concerns. Multiple logistic regression analysis was conducted to check the influence of psychological concerns due to the COVID-19 pandemic on the rate of practicing tooth brushing after lunch. Results: According to occupational classifications, professionals and office workers and career soldiers had 1.551- and 1.581-times higher practicing rates than managers, respectively, whereas machine operators, agricultural and fishery sector workers, and daily laborers had lower practicing rates. Regarding COVID-19-related psychological concerns, the group with a lower concern about infection had a 1.076 times higher practicing rate than that with greater concern. The group with greater concern about blame from neighbors had 1.119 times higher practicing rate than that with lower concern. Conclusion: The correlations between higher economic workers' concerns about infection and blame from neighbors and higher recognition of the necessity to prevent COVID-19 and practice tooth brushing after lunch were confirmed. It is necessary to prepare measures for practicing tooth brushing after lunch suitable to the characteristics of occupational types and work environments of economic workers.

• Imaging Science in Dentistry
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• 제43권4호
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• pp.303-308
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• 2013

This report describes a 31-year-old female patient with six impacted teeth. The crowns of the impacted teeth were surrounded with cyst-like lesions with a mixed internal structure and well-defined cortical borders. Microscopic examination of the specimen obtained from the follicle of the left mandibular third molar tooth revealed loose to moderately dense collagenous connective tissue with abundant calcified material and sparse epithelial islands. A diagnosis of multiple calcifying hyperplastic dental follicles was made.

• 대한소아치과학회지
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• 제45권1호
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• pp.1-9
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• 2018

본 연구의 목적은 다중 회귀 분석을 이용하여 상악 매복 중절치를 교정적 견인한 후 치료 결과에 영향을 미치는 요소를 확인하는 것이다. 2005년 1월부터 2015년 12월까지 연세대학교 치과대학병원 소아치과에서 상악 매복 중절치에 버튼 부착 수술을 동반한 교정적 치료를 받은 소아 청소년 환자 총 83명을 대상으로 환자 정보와 치료 전, 후 방사선학적 정보를 이용하여 연구를 진행하였다. 치료 후 인접한 중절치의 길이에 대한 견인한 중절치의 길이의 비율에 대해 성별, 연령 등 환자 정보의 영향 및 치아 발육 단계, 매복 치아의 높이와 위치, 각도 등 방사선학적 정보의 영향을 다중 회귀 분석을 통하여서 평가하였다. 다중 회귀 분석 결과, stem cell from apical papilla (SCAP)의 높이가 높아질수록 치료 후 치아길이비율은 0.345 단위 증가하였으나(p < 0.01), 성별, 치아 발육 단계, 매복치아와 중심선과의 거리 및 각도, 매복치아의 절단면의 높이는 치료 후 치아길이비율과 통계학적으로 유의미한 차이를 보이지 않았다(p > 0.05). 매복 중절치 교정적 견인 치료 시 견인한 치아의 길이는 초기 SCAP의 높이의 영향을 받으나, 성별, 치아 발육 단계, 중심선과의 각도, 절단면의 높이에 따른 영향은 보이지 않았다.

• 한국CDE학회논문집
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• 제20권4호
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• pp.348-356
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• 2015

It is important to devise methods for assisting dentists to consistently determine implant positions and directions and to accurately perform drilling tasks during dental implant surgery. In this paper, we propose a novel approach to tooth implant placement planning which deals with the determination of the positions and directions of multiple implant fixtures for a set of missing mandibular teeth and suggests the selection of the sizes and types of the implant fixtures. We combine Korean standard data in the sizes and positions of human teeth with the patient specific 3D models of mandibular jawbones, nerve curves, and neighboring teeth around the missing teeth in order to determine the positions and directions of the implant fixtures for the missing teeth. Using the geometric and spatial information of the jawbones, the teeth and the implant fixtures, we can construct the 3D models of surgical guide stents which are crucial to perform drilling tasks with ease and accuracy. Adopted in 3D simulation of dental implant placement, the approach can provide surgeon students with good educational contents. We also expect that, with further work, the approach can be used as a useful tool to plan for dental implant surgery.

• 대한치과교정학회지
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• 제39권2호
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• pp.112-119
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• 2009

본 연구는 다변량 기법을 도입하여 치아 크기의 다양성을 고려하면서 정확성이 높은 혼합치 열기 분석법을 개발하기 위해 시행되었다. 견치 및 소구치 크기를 예측하는 데 이용된 변수는 상악 중절치, 상악 제1대구치, 하악 중절치, 하악 측절치 및 하악 제1대구치로서 총 5개 치아 크기 변수가 이용되었다. 우선 정상교합자 연구 표본 307명을 5개 치아 변수를 이용하여 k-means 군집 분석으로 치아 크기에 따라 나눈 후 판별식을 이용, 치아 크기가 큰 그룹과 작은 그룹으로 분류하였다. 이후 견치와 소구치 크기의 합을 예측하기 위하여 남녀별, 상하악별, 치아 크기 그룹별로 다중선형 분석을 이용하여 회귀식을 구했다. 검증 표본에는 504명의 부정교합자가 이용되었으며, 이들에 대하여 정상교합자로부터 도출된 판별식을 이용하여 2그룹으로 할당한 후 정상교합자로부터 도출된 회귀식을 이용하여 상악과 하악의 견치 및 소구치 크기 합을 예측하였다. 오차 분석 결과 정상교합자는 최대 0.71, 부정교합자 검증표본은 최대 0.82 mm의 residual standard deviation 값을 보였다. 부정교합 분류별, 치아 크기 패턴별로 예측 오차의 유의한 차이는 없었다. 1 mm 및 2 mm 이상의 예측 오차를 보인 빈도는 각각 17.3%와 1.8%였다. 본 연구 결과 도출된 혼합치열기 분석법은 기존의 연구들과 비교하여 그 정확성이 높은 것으로 고찰되었다. 다만, 임상 적용 시 복잡한 계산 과정으로 인하여 전산화 환경에서 더욱 유용할 것으로 생각된다.

• Restorative Dentistry and Endodontics
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• 제44권4호
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• pp.39.1-39.8
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• 2019

The present report presents a case of dens invaginatus (DI) in a patient with 4 maxillary incisors. A 24-year-old female complained of swelling of the maxillary left anterior region and discoloration of the maxillary left anterior tooth. The maxillary left lateral incisor (tooth #22) showed pulp necrosis and a chronic apical abscess, and a periapical X-ray demonstrated DI on bilateral maxillary central and lateral incisors. All teeth responded to a vitality test, except tooth #22. The anatomic form of tooth #22 was similar to that of tooth #12, and both teeth had lingual pits. In addition, panoramic and periapical X-rays demonstrated root canal calcification, such as pulp stones, in the maxillary canines, first and second premolars, and the mandibular incisors, canines, and first premolars bilaterally. The patient underwent root canal treatment of tooth #22 and non-vital tooth bleaching. After a temporary filling material was removed, the invaginated mass was removed using ultrasonic tips under an operating microscope. The working length was established, and the root canal was enlarged up to #50 apical size and obturated with gutta-percha and AH 26 sealer using the continuous wave of condensation technique. Finally, non-vital bleaching was performed, and the access cavity was filled with composite resin.

• 대한치과교정학회지
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• 제51권5호
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• pp.304-312
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• 2021

Objective: This study aimed to compare the amount of tooth movement after multiple horizontal (MH) and single vertical (SV) micro-osteoperforations (MOPs), and evaluate the histological changes after orthodontic force application in rabbits. Methods: The mandibles of 24 white rabbits were subjected to two experimental interventions: MH and SV MOPs. Defect volume of the MOPs between the two groups was kept similar. A force of 100 cN was applied via a coil spring between the incisor teeth and the first premolars. The amount of tooth movement was measured. Differences in the amount of tooth movement and bone variables at three time points and between the two groups were evaluated using repeated-measures analysis of variance. Results: The first premolar showed a mesial movement of 1.47 mm in the MH group and 1.84 mm in the SV group, which was significantly different at Week 3 (p < 0.05). No significant difference was observed in bone volume and bone fraction between the groups. Tartrate-resistant acidic phosphatase-positive cell count was also significantly greater at Week 3 than at Week 1 in both the SV and MH groups. Conclusions: The amount of tooth movement showed significant differences between Weeks 1 and 3 in the SV and MH MOP groups, but showed no differences between the two groups. Therefore, SV MOP could be considered an effective tool for enhancing tooth movement, especially for molar distalization, uprighting, and protraction to an edentulous area.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2007년도 춘계학술대회A
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• pp.712-717
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• 2007

This study deals with the TE(Transmission Error) of gear tooth profile by modifying a profile and lead of a surface of tooth. First, we experimentally confirmed that the TE is a synthesis of the sliding velocity between both gears. Since various types of TE appear in the experiments, we introduced definition of transmission error and the optimism design by modifying a surface parameters. The test stand's performance is then evaluated through a series of multiple torque transmission error tests. Comparisons are made between data recorded before and after the test stand's redesign, and subsequently repeatability studies are performed to verify the veracity of the measured data. Finally, the experimental results are compared to the analytical predictions of two different gear analysis programs.