• 환경생물
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• 제25권1호
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• pp.66-71
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• 2007

실내에서 사육된 C. riparius를 대상으로 내분비계 교란물질인 BPA와 4-nonylphenol을 처리하여 형태적인 변화를 살펴보았다. 약제에 노출된 개체의 하순기절은 부드러워지거나(smooth) 손실(loss)이 가장 많았다. 처리물질에 따른 기형의 정도를 살펴보면, BPA는 $31{\sim}90%$, 4-nonlyphenol은 $40{\sim}80%$의 범위를 보였다. BPA는 처리 농도가 증가할수록 기형도 증가하였으나 4-nonylphenol은 노출농도 증가와 기형발생의 비례적으로 나타나지 않았다. 처리 물질별 하순기절의 기형 부위를 살펴보면, MIX타입의 기형이 가장 많이 나타났으며 그 다음으로 LT, MLT 타입의 기형이 나타났다. MLT에서는 부드러워지는 형태가 가장 많았고 LT에서는 teeth가 손실되는 loss 타입의 기형이 가장 많이 나타났다. 또한 LT에서는 부드러워지는 마모와 손실이 복합적인 타입이 그 다음으로 빈번하였다. MIX는 부드러워지거나 손실 타입의 기형이 가장 다수 관찰되었다.

• 대한소아치과학회지
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• 제24권4호
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• pp.776-780
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• 1997

Patient with alveolar abscess due to dental caries with severe alveolar bone loss, severe tooth mobility, root resorption need extraction of tooth because it is impossible to carry out pulp treatment and restoration by using conventional method. Early loss of primary molar might cause masticatory interference, extrusion of opposing tooth, problem in maintaining space and interference on eruption of permanent tooth. Especially, early loss of primary second molar before the eruption of permanent first molar might cause space closure by mesially erupted permanent first molar and impaction of second premolar. In such a case, distal shoe space maintainer and removable space regaining appliance was the first choice of treatment. But, distal shoe space maintainer need precise adaptation and might cause chronic inflammation if the oral hygiene is poor. In a case using removable space regaining appliance, patient's cooperation is most important. If the distal root of primary second molar is comparably sound and alveolar abscess with alveolar bone loss is localized at mesial root, hemisection should be carried out for precise guide to eruption of the permanent first molar, restoration of masticatory fuction and solution to the discomfort of the patient

• 대한치과보철학회지
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• 제56권4호
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• pp.302-307
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• 2018

다수의 치아 상실과 치아 마모로 인해 교합이 붕괴된 경우 교합 고경의 변경이 필요할 수 있다. 그리고 이러한 경우 심미적이면서도 근신경계와 조화를 이룰 수 있는 고경을 결정하는 것이 중요하다. 본 증례는 치아상실 및 마모로 인해 교합 수직 고경의 감소가 관찰된 환자에서 진단 모형과 방사선 사진 및 다양한 임상적 검사 등의 교합관계분석을 통해 교합 수직 고경을 회복을 동반한 보철 수복을 진행한 경우로, 기능적인 면과 심미적인 면에서 양호한 결과를 얻었기에 이를 보고하는 바이다.

• 대한치과교정학회지
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• 제46권3호
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• pp.155-162
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• 2016

Objective: The aim of this study was to investigate whether labial tooth inclination and alveolar bone loss affect the moment per unit of force ($M_t/F$) in controlled tipping and consequent stresses on the periodontal ligament (PDL). Methods: Three-dimensional models (n = 20) of maxillary central incisors were created with different labial inclinations ($5^{\circ}$, $10^{\circ}$, $15^{\circ}$, and $20^{\circ}$) and different amounts of alveolar bone loss (0, 2, 4, and 6 mm). The $M_t/F$ necessary for controlled tipping ($M_t/F_{cont}$) and the principal stresses on the PDL were calculated for each model separately in a finite element analysis. Results: As labial inclination increased, $M_t/F_{cont}$ and the length of the moment arm decreased. In contrast, increased alveolar bone loss caused increases in $M_t/F_{cont}$ and the length of the moment arm. When $M_t/F$ was near $M_t/F_{cont}$, increases in Mt/F caused compressive stresses to move from a predominantly labial apical region to a palatal apical position, and tensile stresses in the labial area moved from a cervical position to a mid-root position. Although controlled tipping was applied to the incisors, increases in alveolar bone loss and labial tooth inclination caused increases in maximum compressive and tensile stresses at the root apices. Conclusions: Increases in alveolar bone loss and labial tooth inclination caused increases in stresses that might cause root resorption at the root apex, despite the application of controlled tipping to the incisors.

• Journal of Periodontal and Implant Science
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• 제33권2호
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• pp.215-223
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• 2003

The main goal of periodontal treatment is the long-term maintenance of teeth. Periodic maintenance program is need to prevent periodontal disease and maintain healthy periodontium. Hirschfeld and Wasserman(1978) studied 600 treated periodontal patients. This study categorized periodontal patients using well-maintained, downhill, extreme downhill groups. The purpose of our study is to evaluate effect of periodontal treatment and analyse tooth loss after periodontal treatment using this classification. The study population of j9 patients had been treated and maintained for mean 5.8 years. All patients were on a periodic maintenance program at 2-, 3-, 4, or 6-month intends. The avenge age of the patients at the time of original therapy was 49.6 years. To analyse tooth loss, modified classification was used on the basis of response to therapy using by Hirschfeld and Wasserman in 1978. The results were as follows : 1. 59 treated patients were lost mean 1.42 teeth per patient for 5.8 years of maintenance period. 2. Maxillary first molars were most frequently lost but mandibular lateral incisors were lost no tooth during maintenance period. 3. Tooth mortality received surgical treatment had similar to received nonsurgical treatment. 4. Tooth loss was more frequent in maxillary teeth than mandibular teeth, and posterior teeth than anterior teeth, and more frequent tendency in male than female.

• 구강회복응용과학지
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• 제32권2호
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• pp.135-140
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• 2016

사고로 인하여 갑자기 치아를 상실하게 된 환자에게 정신적 안정, 심미성과 기능을 회복하기 위하여 빠른 임시 보철물 수복이 필요하다. 본 증례는 외상으로 인하여 예상치 못한 치아 상실이 발생한 환자에게 열형성 기술(thermoforming technique)을 이용한 수복을 시행하여 만족할 만한 결과를 얻었기에 보고하는 바이다.

• 한국기계가공학회지
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• 제10권4호
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• pp.38-43
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• 2011

Industrial reducer is in general use to Deck Crane. High-precision and high-efficient reducer is minimized the power-loss and energy-loss of a machine. So it contribute the price reduction and life extension. Reducer is usually using the Planetary gear reducer. Planetary gear reducer is composed the sun gear, planet gear, internal gear and casing. Industrial reducer's wear and breakage have a short-life. To solve this problem, it is using the profile-shifted-gear or tooth modification. This study was carried out the effect of addendum modification coefficient on tooth fillet bending strength to planetary reducer. Tooth fillet bending stress is calculate. And all parameter were expressed the function of addendum modification coefficient. And then stress concentration factor of tooth fillet curve was express the function of addendum modification coefficient using comparison between theory and finite element analysis.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2008년도 제39회 하계학술대회
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• pp.760-761
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• 2008

This paper deals with the core loss as well as torque characteristics according to the change of stator shape in an interior permanent magnet synchronous motor (IPMSM). The finite element method and functional core loss data obtained by the steinmetz equation are used in order to estimate the core loss. To minimize the core loss caused by the shape of tooth tip, slot-area and volume of permanent magnet, those are all the same in each model. In the end, the ratio between tooth width and yoke thickness to minimize the core loss in the IPMSM is presented in this paper.

• 한국치위생학회지
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• 제16권4호
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• pp.635-641
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• 2016

Objectives: The purpose of this study is to assess the characteristics of tooth surface after using Gracy curet and Ultrasonic scaler Methods: In this study, 12 teeth extracted were used. 12 specimens were divided into three groups with the same numbers, which were classified into Control group, Gracy curet use group, and Ultrasonic scaler use group, and after performing instrument operation, we measured the roughness and the loss degree of tooth surface by using SEM. Results: In groups using Gracy curet and Ultrasonic scaler, the roughness and the loss of tooth surface increased significantly(p<0.05). In the roughness of groups using Gracy curet and Ultrasonic scaler, Ultrasonic scaler group was higher in crown, but Gracy curet group was higher in root. As a result of observation through SEM, the roughness and the loss degree increased in order of Control group, Ultrasonic scaler use group, and Gracy curet use group. Conclusions: Taken together above results, both hand instrument and ultrasound equipment create roughness and loss in crown and in root, and hand instruments makes rougher than ultrasonic instruments in root, so it is thought to require thorough and accurate technical application not to damage tooth surface when removing plaque.

• 한국치위생학회지
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• 제20권3호
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• pp.335-346
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• 2020

Objectives: This study investigated the association between oral health and suicide attempts in adults aged 65 years or older using the 7^th Korea National Health and Examination Survey (KHANES, 2016-2018). Methods: Of the total 24,269 participants of the 7^th KHANES (2016-2018), 1,488 adults aged 65 years or older who had an oral health examination were selected. Variations in suicide attempts with demographic characteristics and perceived oral health status were analyzed using the χ² test, and the association between oral health and suicide attempts was analyzed using the logistic regression model. Results: The suicide attempt rate was higher among older adults with chewing (p<0.01) and speaking (p<0.05) difficulties. The odds ratio for a suicide attempt was 1.05 times higher among those with tooth loss (p<0.05). Conclusions: Our results showed that older adults with tooth loss had an increased risk of suicide. Thus, it is important to prevent tooth loss, in the first place, through proper oral health management. If tooth loss occurs, appropriate treatment should be prioritized to facilitate functional recovery. Finally, national support is required for older adults with limited access to dental care.