• Imaging Science in Dentistry
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• 제38권1호
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• pp.49-56
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• 2008

Purpose: Diagnostic estimation of destruction and formation of bone has the typical limit according to capacity of x-ray generator and image detector. So the aim of this study was to find out how much it can reproduce the shape and the density of bone in the case of using recently developed dental type of cone beam computed tomography, and which image is applied by new detector and mathematic calculation. Materials and Methods: Cone beam computed tomography (PSR 9000N, Asahi Roentgen Ind. Co., Ltd., Japan) and soft x-ray radiography were executed on dry mandible that was already decalcified during 5 hours, 10 hours, 15 hours, 20 hours, and 25 hours. Estimating and comparing of those came to the following results. Results: The change of inferior border of mandible and anterior border of ramus in the region of cortical bone was observed between first 5 and 10 hours of decalcification. The reproduction of shape and density in the region of cortical bone and cancellous bone can be hardly observed at cone beam computed tomography compared with soft x-ray radiography. The difference of decrease of bone density according to hours of decalcification increase wasn't reproduced at cone beam computed tomography compared with soft x-ray radiography. Conclusion: CBCT images revealed higher spatial resolution. However, contrast resolution in region of low contrast sensitivity is the inferiority of images' property.

• 한국환경보건학회지
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• 제24권3호
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• pp.11-17
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• 1998

Chitin is known as biodegradable natural polymer. In spite of various application of chitin derivatives from waste marine sources, commercial use of chitin has been limited due to high resistance to chemicals and the absense of proper solvents. We chitin prepared through the decalcification, bleaching and deproteination from Protunus trituberculatus shells by change of Hackman's method. Also, Microcrystalline chitin made by hydrolysis that was reduce made of resistance solvents used by dilute hydrochloric acid, ultrasonic and hydrogen peroxide. Crosslinked chitin derivatives were preparaed from chitin with crosslink agents(epichlorohydrin, 1,3-dichloropropanol) follwed by crosslinkage at 6C position. The effects of these parameters on chitin dervatives were invastigated by IR, DSC, XRD, BET, PSA and SEM. SEM analysis showed that both chitin and crosslinked chitin had a particle shaped morphology.

• 한국식품위생안전성학회지
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• 제14권1호
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• pp.22-26
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• 1999

The purpose of this experiment was to examine the antimicrobial effect of the natural flavonoid hesperidin on dental caries and alveolar bone resorption in the albinorats. Twenty five day old male rats were fed with the experimental diets for 42 days. At the end of the 42 day experimental period, the molar tooth occlusal surface was examined by a dissecting microscope. The sulcular caries lesions were recorded: the first molar caries incidence was higher than that of the second molar and the third molar. Alvelolar bone resorption was measured on the buccal and lingual aspects of each molars. Three measurements were taken on the first molar (mesialpoint, midpoint, distalpoint). The results of this experiments, showed that hesperidin is effective in reducing dental caries and alveolar bone resorption.

• 대한자원환경지질학회:학술대회논문집
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• 대한자원환경지질학회 2003년도 춘계 학술발표회 논문집
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• pp.315-315
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• 2003

Gold mineralization at Kyaukpahto occurs as stockworks/disseminations and locally as breccia zones in silicified sandstones of Lower to Middle Eocene Male Formation of Myanmar. The mineralization is spatially related with NNE -trending fracture zones_probably tensional open fractures caused by the right-lateral Sagaing fault system. Intensive silicification, sericitization, argillic alteration, sulfidation, and decalcification are recognized in the Kyaukpahto mine area. (omitted)

• Journal of Chest Surgery
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• 제55권2호
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• pp.177-179
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• 2022

Barlow's disease with mitral annular calcification encompassing the subvalvular apparatus, including the valve leaflet and chordae, is extremely rare, and mitral valve repair in such cases is challenging. We report a case of a 60-year-old woman with mitral valve regurgitation that was successfully controlled by resecting the rough zone of P2 and calcifications on the excess leaflet regions and subvalvular apparatus, while retaining the calcification of P3 and implanting artificial chordae and an annuloplasty ring. Mitral valve repair for such cases requires an individualized and compounded surgical strategy for the technique to treat Barlow's disease and manage calcification to control mitral regurgitation.

• 대한치과교정학회지
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• 제29권5호
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• pp.589-597
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• 1999

본 연구는 불소가 유리되는 교정용 전색제의 법랑질 탈회에 대한 효과를 미세경도법을 통해 실험적으로 규명하기 위해 112개의 치아를7개의 군으로 나누어 실험편을 제작한 뒤, 4개의 군에 광중합형 (L1군, L2군)및 자가 중합형 (S1군, S2군) 교정용 전색제인 $FluoroBond^{\circledR}$를 실험편에 도포하고 인공우식용액하에서 실험적으로 처리 완료된 실험편에 Knoop indenter를 부착한 Tukon microhardness tester를 이용해 미세경도를 측정하였고, 이를 KHN(Knoop hardness number)으로 환산하고 조직의 변성 여부를 검색하여 다음과 같은 결과를 얻었다. 1. 법랑질 깊이에 따른 미세경도는 모든군의 $50{\mu}m$ 깊이에서 최소였고, $200{\mu}m$에서 최고인 L2군을 제외한 모든군의 $300{\mu}m$ 깊이에서 최고의 수치를 보였으며, L2, S2군을 제외한 모든군에서 법랑질 깊이가 증가됨에 따라 미세경도치도 증가되었다. 2. 광중합형 및 자가중합형 교정용 전색제 군 모두 어느정도 치아우식에 저항하는 예방효과를 가지고 있었으나 통계학적인 유의성은 없었다(p>0.05). 3. 광중합형 교정용 전색제는 법랑질 깊이 $100{\mu}m,150{\mu}m,200{\mu}m$에서 치아우식 진행 억제효과가 있었다 (p<0.05). 4. 자가중합형 교정용 전색제는 법랑질 깊이 $150{\mu}m$에서 치아우식 진행 억제효과가 있었다 (p<0.05). 5. 광중합형 교정용 전색제 군과 자가중합형 교정용 전색제 군 사이의 법랑질 탈회 억제효과의 차이는 없었다 (p>0.05).

• Journal of Periodontal and Implant Science
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• 제26권4호
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• pp.779-797
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• 1996

치주 질환에 의해 상실된 치주 조직의 재생과 기능 회복을 위해 골 이식재의 사용을 포함한 많은 치료법들이 이용되었다. 골 이식술을 위해 자가골 이식, 동종골 이식, 이종골 이식, 골 대체 물둥이 이용되어왔다. 이중 탈회 냉동 건조 동종골은 약 20년 전부터 치주 영역에서 사용되어 왔으나 탈회 냉동 건조 동종골의 골내 치주낭 이식의 효과에 대한 연구는 찬반 양론이 대립된다. 탈회 냉동 건조골은 제작 방법 중 특히, 탈회에 의해 탈회 냉동 건조골의 생물학적 성격이 결정되며 이에 따라 치주 조직 재생 능력에도 변화가 있을 수 있다. 이에 본 연구에서는 탈회 시간에 따른 탈회 냉동 건조골 이식이 성견의 3면 골내 치주낭에서 치주 조직 재생에 미치는 영향을 알아보고자 성견의 전치부에 $4mm{\times}4mm{\times}4mm$크기의 3면 골 내낭을 형성한 후 치주 수술만 시행한 군을 대조군으로, 탈회를 시키지 않은 냉동 건조골을 이 식한 군을 실험 I 군으로, 12 시간 탈회시킨 탈회 냉동 건조골을 이식한 군을 실험 n군으로, 24시간 탈회시킨 탈회 냉동 건조골을 이식한 군을 실험 III군으로 설정하여 14주 후에 치유 결과를 조직학적으로 비교 관찰하여 다음과 같은 결과를 얻었다. 1. 결합 조직 유착은 대조군에서 $0.62{\pm}0.14mm$, 실험 I 군에서 $0.42{\pm}0.11mm$, 실험 n군에서 $0.63{\pm}0.43mm$, 실험 III군에서 $0.52{\pm}0.11mm$로 계측되었으며 대조군과 실험군간에 유의성 있는 차이는 없었다. 2. 신생골 형성은 대조군에서 $3.17{\pm}0.24mm$, 실험 I군에서 $3.15{\pm}0.56mm$, 실험 n 군에서 $3.22{\pm}0.36mm$, 실험 III군에서 $3.28{\pm}0.74mm$ 로 계측되었으며 대조군과 실험군간에 유의성 있는 차이는 없었다. 3. 신생 백악질 형성은 대조군에서 $4.19{\pm}0.46mm$, 실험 I군에서 $3.23{\pm}0.64mm$, 실험 II군에서 $4.13{\pm}1.82mm$, 실험 III군에서 $3.13{\pm}0.62mm$로 계측되었으며 대조군과 실험군간에 유의성 있는 차이는 없었다.

• 대한치과교정학회지
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• 제33권5호
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• pp.381-389
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• 2003

본 연구는 치아우식증에 관련된 Hutans streptococci 표준균주 및 임상분리 균주의 성장억제를 유도할 수 있는 천연생약추출물을 검색하기 위하여 실시되었다. 녹차추출물은 CHMC-2032를 사용하였으며, 결명자 추출물은 $50\%$ 에탄올을 이용하여얻었다. 이들 추출물의 Mutans streptococci표준균주 및 교정환자들에서 브라켓과 치면 사이의 경계부에서 분리된 각각 10 균주씩의 S. mutans 및 S. sobrinus에 대한 최소성장억제농도를 액체배지 희석법으로 구하였다. 그 결과 CHMC-2032의 S. mutans 및 S. sobrinus의 표준 균주, S. sobrinus의 대부분 임상분리 균주에 대한 최소성장 억제농도는 5mg/ml이었다 그러나 결명자 추출물에 의한 S. mutans 및 S. sobrinus에 대한 세균 성장억제 효과는 미미하였다. 본 연구 결과 치아우식증의 예방적 측면에서 결명자차보다는 녹차를 마시는 것이 유리하며, CHMC-2032를 이용하여 구강양치용액을 제조하여 사용할 경우 교정환자를 포함하여 대부분의 사람에게서 치아우식증 예방 효과가 있으리고 추정된다.

• 대한치과의사협회지
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• 제50권7호
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• pp.394-406
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• 2012

Objective: The adhesion capabilities of different types of self-ligating brackets were measured with respect to Streptococcus mutans and Streptococcus sobrinus. Methods: Five types of self-ligating brackets (Clippy-C; Mini Clippy; Clarity-SL; Speed; Damon 3) were used for the experiment group and composite resin brackets (Spirit-MB), metal brackets (Victory) and polycrystalline alumina brackets (Clarity) were used for the control group. In order to assess adhesion of bacteria to the brackets, the brackets were cultured for 3, 6 and 24 hours in media containing bacteria and 20% sucrose. Results: There was no statistic difference in adhesion amount of Streptococcus mutans and Streptococcus sobrinus according to the types of brackets. A total adhesion amount according to bracket type was different. An extended incubation time increased adhesion amount. Observation under scanning electron microscope showed that Streptococcus sobrinus adhered more to Clippy-C and Victory rather than to Clarity-SL. Conclusions: Clarity-SL, a self-ligating esthetic bracket was confirmed to show lower bacterial adhesion to cariogenic bacteria, Streptococcus mutans and Streptococcus sobrinus group than other self-ligating brackets or conventional brackets, which suggests that proper use of self-ligating esthetic brackets might even be better in preventing tooth surface decalcification.

• 대한치과의사협회지
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• 제54권5호
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• pp.348-355
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• 2016

Ideal autogenous or allogenic bone graft materials should provide 1) stabilization of blood clot, 2) scaffolds for cellular proliferation and differentiation, 3) release of osteogenic growth factors, 4) appropriate resorption profile for remodeling of new bone. Teeth, especially dentin, mostly contain hydroxyapatite and type I collagen which are similar to bone, and could be valuable graft material. Clinically teeth are used as calcined or demineralized forms. Demineralized form of dentin can be more effective as a graft material. But a conventional decalcification method takes time and long treatment time may give negative effects to various osteogenic proteins in dentin. Author used a new clinical method to prepare autogenous teeth, which could be grafted into the removal defects immediately after extraction using vacuum ultrasonic system. The process could be finished within two hours regardless of the form (powder, chip or block). Teeth were processed to graft materials in block, chip, or powder types immediately after extraction. It took 120 minutes to prepare block types and 40 minutes to prepare powder. Clinical cases did not show any adverse response and the healing was favorable. Rapid preparation of autogenous teeth with the vacuum ultrasonic system could make the immediate one-day extraction and graft possible.