• 센서학회지
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• 제9권3호
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• pp.163-170
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• 2000

광주파수 변조 광섬유 간섭형 센서가 변위, 변형률 및 힘 등의 물리량을 측정하기 위하여 개발되어졌다. 일반적인 광섬유 간섭형 센서는 물리량에 따라 단지 정현파 형태의 신호를 보이기 때문에 물리량의 증감을 구별하는 것이 매우 어렵다. 본 연구에서는 물리량의 증감 방향을 구별하면서 물리량을 측정하기 위하여 단지 톱니파형으로 변조시킨 광원만을 사용하는 광섬유 마이켈슨 센서를 성하였다. 센서 출력은 일정한 정현파가 출력되도록 조절되어졌다. 출력신호는 일정 시간 간격동안 파형의 개수를 계수함에 의하여 처리되어졌다. 변형률은 파형 개수 변화량에 변형률을 구하기 위한 게이지 상수만을 곱함에 의하여 계산되었다. 이 센서의 변형률 측정 성능을 검토하기 위하여 광섬유 센서와 전기저항형 변형률 게이지가 부착된 알루미늄 시험편을 사용하여 만능시험기로 반복하중을 가하여 변형률의 증감을 측정하는 실험을 수행하였다. 이 실험으로부터 광섬유 센서에 의하여 측정된 변형률 변화량이 전기저항형 변형률 게이지의 변화량과 잘 일치하고 있음을 확인할 수 있었다.

• 동의생리병리학회지
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• 제19권1호
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• pp.87-91
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• 2005

Dental plaque is a film of microorganisms on the tooth surface that plays an important part in the development of caries and periodontal diseases. Streptococcus mutans (S. mutans) is present in almost all types of dental plaque. Teeth and their supporting structure, the gums (gingiva) are subjected to infection by S. mutans that causes cavities and pyorrhea which, if left untreated, can eventually lead to gingivitis. Various chemical agents have been evaluated over the years with respect to their antimicrobial effects in the oral cavity; however, all are associated with side effects that prohibit regular long-term use. The present study was designed to investigate the effect of Aralia continentalis (Araliaceae) extracts on the growth, acid production, adhesion, and insoluble glucan synthesis of S. mutans. The methanol extract of A. continentalis showed concentration dependent inhibitory activity against the growth and acid production of S. mutans, and produced significant inhibition at the concentration of 0.25, 0.5, 1, 2 and 4 mg/ml compared to the control group. The extracts markedly inhibited S. mutans adherence to HA treated with saliva, and cell adherence was repressed by more than 60% at the concentration of 0.25 mg/ml and complete inhibition was observed at the concentration of 4 mg/ml. On the activity of glucosyltransferase which synthesizes water insoluble glucan from sucrose, methanol extract of A. continentalis showed more than 10% inhibition over the concentration of 0.25 mg/ml. The synthesis of insoluble glucan was decreased in the presence of 0.25 - 4 mg/ml of the methanol extract of A. continentalis. Hence, we conclude that A. continentalis might be a candidate of anticaries agent.

• 한국치위생학회지
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• 제10권3호
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• pp.523-530
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• 2010

Objectives : In order to provide basic data necessary for developing oral health education plane for school continued oral health education by understanding knowledge and activities of oral health. Methods : This study was performed against 324 students at 5th grade of 2 elementary schools in Iksan-si, Jellabuk-do selected through convenience sampling, who were in mixed dentition period that might experience dental caries of permanent tooth. Results : As results, For the knowledge level on oral health by questions, it was found that the case that the elementary school students had correct knowledge on oral health was 'chocolates, snacks, and candies were foods that might often cause dental caries' and 95.8% of the students recognized it well. It was found that for 'must do toothbrushing before going to bed', 'during toothbrushing, I clean my tongue', and 'Proper time necessary for toothbrushing is about 3 minutes', 89.3%, 93.2%, and 89.3% of the students knew the, respectively. When oral health knowledge level by groups was divided into 3 groups and observed, they were classified into Low (0-4 points), Mid (5-7 points), and High (8-10 points). It was found that the knowledge level of each group was High 64.1%, Mid 33.9%, and Low 2.0% and it was identified that the high group took the largest ratio. It was suggested also for oral health knowledge level depending on their father's academic background that there was a statistically significant difference in the group higher than university graduate(p<.05). It was found for oral health knowledge level depending on parents' dental condition that an answer that both parents were good was high and there was a statistically significant difference. But post-analysis resulted that there was no apparent difference among groups. It was found that the ratio of respondents who answered for toothbrushing method 'toothbrush should be moved and rotated downward for the upper teeth and upward for the lower teeth to clean the teeth and gum' were 33.2% of male students and 29.4% of female students and showed statistically significant difference (p<0.05). It was found also that the ratio of respondents who answered to use a toothbrush for about 3 months' were 29.4% of male students and 25.5% of female students and showed statistically significant difference (p<0.05). Conclusions : Oral health program through the elementary school students and their parents for the development of proper oral health care education programs continue to be made should be considered.

• Maxillofacial Plastic and Reconstructive Surgery
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• 제41권
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• pp.4.1-4.10
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• 2019

Background: The mandibular third molar (M3) is typically the last permanent tooth to erupt because of insufficient space and thick soft tissues covering its surface. Problems such as alveolar bone loss, development of a periodontal pocket, exposure of cementum, gingival recession, and dental caries can be found in the adjacent second molars (M2) following M3 extraction. The specific aims of the study were to assess the amount and rate of bone regeneration on the distal surface of M2 and to evaluate the aspects of bone regeneration in terms of varying degree of impaction. Methods: Four series of panoramic radiographic images were obtained from the selected cases, including images from the first visit, immediately after extraction, 6 weeks, and 6 months after extraction. ImageJ software^® (NIH, USA) was used to measure linear distance from the region of interest to the distal root of the adjacent M2. Radiographic infrabony defect (RID) values were calculated from the measured radiographic bone height and cementoenamel junction with distortion compensation. Repeated measures of analysis of variance and one-way analysis of variance were conducted to analyze the statistical significant difference between RID and time, and a Spearman correlation test was conducted to assess the relationship between Pederson's difficulty index (DI) and RID. Results: A large RID (> 6 mm) can be reduced gradually and consistently over time. More than half of the samples recovered nearly to their normal healthy condition (RID ≤ 3 mm) by the 6-month follow-up. DI affected the first 6 weeks of post-extraction period and only showed a significant positive correlation with respect to the difference between baseline and final RID. Conclusions: Additional treatments on M2 for a minimum of 6 months after an M3 extraction could be recommended. Although DI may affect bone regeneration during the early healing period, further study is required to elucidate any possible factors associated with the healing process. The DI does not cause any long-term adverse effects on bone regeneration after surgical extraction.

• 대한소아치과학회지
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• 제43권3호
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• pp.313-319
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• 2016

Wolf-Hirschhorn syndrome (WHS)은 4번 염색체 단완의 결실로 발생하며, 지능 및 성장 발달의 저하, 경련, 선천성 심기형과 특징적인 두개안면기형 등을 초래하는 질환이다. 사이가 넓고 돌출된 미간과 코의 기저부가 넓은 특징을 보이는 얼굴 모양은 그리스 전사의 투구(Greek warrior helmet appearance) 와 비슷한 모양을 보인다. 구강 내에서는 구순열, 우상치아, 원뿔형 치관, 다수의 결손치와 이로 인한 만기 잔존 유치 등의 소견을 보인다. 본 증례는 충치치료를 주소로 내원한 9세 여환으로 타병원에서 WHS으로 진단받았으며, 성장 지연, 정신 박약 및 WHS의 특징적인 얼굴 형태를 보였다. 구강 검사를 통해 다수의 영구치 결손과 만기 잔존된 유치 및 다수의 충치를 관찰하였으며, 환자의 협조도 미약으로 전신마취 하에 충치치료 하였다. 다수의 영구치 결손으로 현재 맹출한 영구치 및 유치의 관리가 중요하고, 이를 위해서는 구강 위생 관리 및 불소도포를 위해 주기적인 치과 검진이 필요하다.

• 대한소아치과학회지
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• 제34권4호
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• pp.613-622
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• 2007

본 연구의 목적은 법랑질 시편에 수종의 불소 제재를 도포한 후 우식 예방 효과를 광밀도 및 미세경도 측정을 통해 평가하는 것이다. 소의 절치를 이용하여 80개의 법랑질 시편을 제작하고 각 군당 20개씩, 네 군으로 나누었다. I군은 대조군으로서 아무런 처치도 하지 않았고 II군은 acidulated phosphate fluoride(APF) gel(60 seconds $taste^{(R)}$, PASCAL, USA)을 4분간 적용한 후 수세하였다. III군은 Fluor $Protector^{(R)}$(Ivoclar Vivadent, Liechtenstein)를, IV군은 $CavityShield^{TM}$(Omnii Pharmaceuticals, USA)를 1분간 도포하고 증류수에 보관한 뒤 24시간 후 부드러운 모를 가진 칫솔을 이용하여 칫솔질하였다. 각 시편을 인공우식용액에 48시간동안 침잠시켜 인공우식병소를 유발한 후 광밀도를 컴퓨터 영상분석 프로그램으로 분석하고 표면미세경도를 측정하여 다음의 결과를 얻었다. 1. 광밀도는 APF gel을 도포한 II군에 비해 불소 바니쉬를 도포한 III, IV군이 높았으나(p<0.05) III군과 IV군 사이의 유의한 차이는 없었다. 2. 표면미세경도는 IV군, III군, II군, I군의 순으로 높았다(p<0.05). 3. $CavityShield^{TM}$를 도포한 IV군과 Fluor $Protector^{(R)}$를 도포한 III군은 광밀도에서는 유의한 차이가 없었으나 표면 미세경도는 IV군이 III군보다 유의하게 높았다. 이상의 결과를 종합해 볼 때 불소 바니쉬가 APF gel에 비해 법랑질 탈회 억제 효과가 우수한 것으로 나타났다. 임상적용의 용이성과 안전성을 고려할 때 불소 바니쉬의 사용이 영유아나 장애인에게 유용할 것으로 사료된다.

• 대한소아치과학회지
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• 제45권2호
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• pp.203-214
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• 2018

상악 견치가 매복 시에 종종 인접 전치 치근의 치근흡수가 나타난다. 심각한 전치의 치근 흡수는 치아의 장기적인 예후를 불량하게 하기도 한다. 이 연구의 목적은 3차원 영상을 이용하여 상악 견치에 의한 전치의 치근 흡수를 관찰하고 관련된 요인을 분석하는 것이다. 연구 대상자는 상악 견치 매복을 가진 65명의 어린이로 총 88개의 치아에 대해 65개의 cone-beam computed tomography 영상을 분석하였다. 그 결과, 상악 견치의 치근 발달 정도와 치근단공의 폐쇄 및 치관의 근원심적인 위치가 중절치의 치근흡수와 유의한 관계를 나타내였다. 측절치의 치근 흡수 여부는 환아의 성별, 나이, 상악 견치의 협설 위치, 수직적 위치에 영향을 받았다. 상악 견치 치배의 확장은 중절치와 측절치의 치근 흡수 여부와 유의한 관계가 없어, 치배의 확장이 치근 흡수에 직접적인 역할을 하지 않는 것으로 나타났다. 상악 견치의 매복 시에 전치의 치근 흡수는 예측하기 어렵기 때문에, 3차원 영상을 이용한 조기 진단이 필요하다.

• 대한심미치과학회지
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• 제22권1호
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• pp.47-55
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• 2013

치아의 상실로 인한 국소적 치조제 결손(localized alveolar defect)은 고정성 국소의치(fixed partial denture) 제작시에 많은 기능적, 심미적 문제점들을 야기한다. 특히 전치부에서의 치조제 결손 부위는 그 형태와 양상에 따라서 심미적 결과에 많은 영향을 미치게 되는데, 이 결손 부위의 회복 여부가 최종적인 심미적 결과의 성패를 좌우하게 된다. 치조제 결손의 양상은 발치 전 치조골의 상황과 염증 정도에 따라 다양하게 나타날 수 있는데, 그 양상은 크게 보면 수평적, 수직적, 혹은 복합적 결손 등으로 분류할 수 있다. 이러한 결손부의 형태와 양에 따라서 우리가 회복시켜 주어야 할 정도도 다르고, 그 난이도 또한 다르다고 할 수 있다. 여기에 추가적으로 고려되어야 할 요소가 결손부와 자연치가 만나는 proximal gingival height이다. 인접 치아와 접하는 gingival height는 그 부위의 치조골 높이에 많은 영향을 받게 되는데, 만약 이 부위에 결손이 존재한다면 역시 심미적 결과에 부정적인 영향을 줄 것이다. 하지만 결손부위 내에서도 치아와 인접한 부위의 gingival height를 동시에 증대시키기 위해 소개된 technique은 많지 않으며 시술의 예지성도 높지 않은 것이 사실이다. 이 case report에서 필자는 수평적 혹은 수직적 결손 및 복합적 결손에 다양하게 적용 가능하면서도 인접치아와 인접한 부위의 gingival height에도 도움이 될 수 있는 술식을 소개하려고 한다.

• Journal of Periodontal and Implant Science
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• 제34권1호
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• pp.71-81
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• 2004

Peri-implantitis could be the result of biomechanical and occlusal overload as well as microbiologic invasion. The dental implant may be more susceptible to dental plaque than the natural tooth, as the predictability of a stable soft tissue attachment complex has not yet been confirmed. With the development of peri-implantitis, the implant surface would be exposed to the oral environment and becomes coated with bacteria. The objective of therapy for this condition is to regain integration of the implant with bone. Since fibroblast adherence to surfaces is impeded by endotoxin, it would seem that decontamination would be desirable to obtain maximum osseointegration. The purpose of this study was to determine whether various chemotherapeutic and mechanical treatments(distilled water, air-powder abrasive, hypersaturated citric acid, tetracycline) can detoxify contaminated titanium implant surface by means of kinetic LAL test. Experimental rough surface titanium disks were fabricated. All of them were divided into two groups(A.a group and P.g group) and each contaminated by A. actinomycetemcomitans and P. gingivalis suspension. Contaminated disks were treated with distilled water, air-powder abrasive, citric acid and tetracycline, and then all disks were placed into LPS-free water for elution. The results were as follows : 1. In A.a group, LPS elute level of all test groups were significantly lower than control group(p<0.05). 2. In A.a group, LPS elute level of test 2, test 3 and test4 groups were significantly lower than that of control group(p<0.05). But, among the test 2, test 3, test4 groups, the significant differences were not detected. 3. In P.g group, LPS elute level of test 2, test 3 and test 4 groups were lower than that of control group(p<0.05). But, among the test groups, the significant differences were not detected. From the result of this study, it would be concluded that air-powder abrasive, hypersaturated citric acid and tetracycline treatments may be effective at reducing endotoxin level on rough titanium implant surfaces, and can be clinically used. But the treatments in peri-implantitis differentially impact osseointegration making one method clinically superior. To gain this knowledges, further molecular biologic and histopathologic studies should be developed.

• Journal of Periodontal and Implant Science
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• 제37권1호
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• pp.35-44
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• 2007

Periodontal ligament (PDL) is the connective tissue located between the tooth root and alveolar bone. In a previous study, PDLs22 was isolated as a PDL-specific gene by using subtractive hybrid-ization between cultured PDL fibroblasts and gingival fibroblasts. It was also suggested that PDLs22 plays important roles in the development, differentiation and maintenance of periodontal tissues. However, little is known about functional study of PDLs22 using recombinant protein in PDL fibroblast differentiation and periodontium formation. In this study, in order to produce the PDLs22 recombinat protein, PDLs22 expression vector were constructed and expressed its protein in various host cell and temperature conditions. The results were as follows: 1. PDLs22 protein was not strongly expressed In the induction system using pRSET-PDLs22 construct. 2. When the BL21(DE3) pLysS was used as a expression host, PDLS22 protein was strongly ex-pressed in the induction system using pHCEIIBNd-PDLs22 construct. 3. The PDLs22 protein was recognized at a molecular weight of 28 kDa in western blots. 4. Almost of the expressed PDLs22 protein was not soluble and observed like as inclusion body. 5. The protein solubility was not improved after modification of induction time and temperature during PDLs22 protein production. In this study, the system for the PDLs22 protein production was connstructed. However, the re-results suggest that further studies will be needed to produce the considerable amount of PDLs22 re-combinat protein, which can use for the periodontal regeneration.