• Restorative Dentistry and Endodontics
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• 제32권1호
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• pp.61-68
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• 2007

이 연구의 목적은 네 종류 file systems의 중심유지능과 근관성형 전후의 상아질 삭제량을 비교하는 것이다. 10-20도의 만곡을 갖는 발거된 20개의 하악 제1대구치의 근심근관(총 40개의 근관)을 근관성형 전에 X선 미세단층촬영 스캐너를 이용하여 스캔하였다. 제 1군은 근관부를 넓힌 후 stainless steel K-Flexofile을 사용하여 step-back technique으로 근관성형하였고, 나머지 군들은 각 제조사의 추천대로 ProFile system (2군), ProTaper system (3군), K3 system (4군)을 사용하여 crown-down technique으로 근관성형하였다. 모든 근관의 근단부 기구조작은 #25 크기까지 시행하였고 근관성형 후 스캔하였다. 3차원 영상 소프트웨어로 근관성형 전후의 스캔된 이미지들을 재구성하여 근관의 전체적 부피 변화를 측정하였다. 또한, 근단공으로부티 1, 3, 5, 7 mm되는 지점의 근관 횡단면을 비교하여 근관성형 전후의 단면적 변화와 중심변위율을 산출하였다. 그 결과, ProTaper와 K3가 다른 file systems보다 상아질을 더 많이 삭제하는 경향을 보였고 모든 실험군에서 중심 변위율은 근단공으로부터 3 mm 지점에서 가장 낮은 수치를 나타냈으며, 3 mm 지점을 제외하고는 ProTaper가 다른 file systems보다 중심유지능이 떨어지는 결과를 얻을 수 있었다 (P < 0.05).

• 대한치과교정학회지
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• 제48권4호
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• pp.268-280
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• 2018

Resistance to sliding (RS) between the bracket, wire, and ligature has been largely debated in orthodontics. Despite the extensive number of published studies, the lack of discussion of the methods used has led to little understanding of this phenomenon. The aim of this study was to discuss variables affecting RS in orthodontics and to suggest an operative protocol. The search included $PubMed^{(c)}$, $Medline^{(c)}$, and the Cochrane $Library^{(c)}$. References of full-text articles were manually analyzed. English-language articles published between January 2007 and January 2017 that performed an in vitro analysis of RS between the bracket, wire, and ligature were included. Study methods were analyzed based on the study design, description of materials, and experimental setup, and a protocol to standardize the testing methods was proposed. From 404 articles identified from the database search and 242 records selected from published references, 101 were eligible for the qualitative analysis, and six for the quantitative synthesis. One or more experimental parameters were incompatible and a meta-analysis was not performed. Major factors regarding the study design, materials, and experimental setup were not clearly described by most studies. The normal force, that is the force perpendicular to the sliding of the wire and one of the most relevant variable in RS, was not considered by most studies. Different variables were introduced, often acting as confounding factors. A protocol was suggested to standardize testing procedures and enhance the understanding of in vitro findings.

• 대한치과의사협회지
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• 제45권6호통권457호
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• pp.362-369
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• 2007

The aim of this study was to investigate the effect of the hybrid instrumentation method with ProTaper and ProFile on the change of root canal area and distance from the canal to the root surface after canal shaping. The mesial canals of twenty extracted mandibular first molars having $10-20^{\circ}\Delta$ curvature were scanned using X-ray microcomputed tomography (XMCT)-scanner before root canals were instrumented. They were divided into four groups (n=10 canals ter group). In Group 1, root canals were instrumented by the step-back technique with stainless steel K-Flexofile after coronal flaring. The remainders were instrumented by the crown-down technique with, ProTaper system (Group 2), ProFile (Group 3) or ProTaper (Group 4). All canals were prepared up to size 25 at the end-point of preparation and scanned again. Pre- and post-operative cross-sectional images of 1, 3, 5, and 7 mm from the apical foramen were compared. For each level, change of cross-sectional canal are and distance to the nearest external root surface was calculated using Adobe Photoshop 6.0 and image software program. In the change of cross-sectional area, Group 4 was less than Group 2 at 3 mm and 5 mm level (p<0.05). In the difference of the distance from the canal to the root surface after canal shaping, Group 4 was least among the other groups at 7 mm level (p<0.05). According to the results, the methods using ProFile or K file only and the hybrid instrumentation technique using ProTaper and ProFile are more appropriate methods of canal preparation than ProTaper system for narrow of curved canals.

• 대한치과기공학회지
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• 제25권1호
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• pp.161-171
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• 2003

The purpose of this study is to examine the effect of parents knowledge on oral health status toward their children. This study was carried out to investigate and analyze the cognitive degree of dental subjects and general public who have an experience to be treated for their dental knowledge, operative dentistry, and dental prothesis in the oral health care through the questionnaires. The results are as follows : 1 : In questioning the frequency in the visitation of dental clinic, 68.8% usually go to see dentists, if children's teeth have trouble. It was the reason that economical standard and educational level were enhanced as before. 57.6% took a kind of medical measures. 2 : In surveying the preference of dentists’ age or gender, 56.9% preferred younger dentists to older or female dentists. On the contrary, 56.9% children want younger dentists, and 64.8% children want female dentist doctor. As a conclusion, the preference of dentists’ age or gender is relevant with a view to remove big horror, which can be evoked by dental measures. 3 : In questioning the possession amount of decayed teeth, 45.8% have more than four. Usually those parents who have children filled their decayed teeth with artificial or installed with dental prosthesis. As a conclusion, age is relevant in this study in p<0.05 level. 4 : In asking for efficient starting-year of tooth brushing, 42.6% said that 2 or 3 year age is the most efficient, and especially 80.6% teach children to learn brushing themselves. (P<0.05). As a conclusion, the voluntary brushing can be good behaviour for good dental health. 5 : In surveying the way they obtained dental information, 38.9% were given form mass media, but 90% were once not delivered with the education of dental health. Because parents have been known narrow and deficient information of dental health through mass media, experts in dental health have to deliver help their parents to be delivered with systematical dental information. The conclusion of this study can be summarized that parents' role is very important to their children's tooth health and the education program for systematical dental information should be delivered to their parents.

• 대한치과기공학회지
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• 제29권2호
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• pp.49-64
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• 2007

This research collected the curriculum for Dental Technology from a total of 20 schools -3-year colleges and 4-year colleges- all in Korea. And we analyzed the average credits of subjects from students. As a result of this analysis, we get the conclusion below: 1. In a distribution which students answered about each subjects; Seminar, Dental morphology I II, Dental morphology practice I II, and Dental devices & instruments don't have many credits and mostly have a converged tendency in high points, according to the arithmetic mean of the major basis subjects. 2. In an analysis of the correlation which is based on the distinction of sex: Complete denture prosthodontics I II III, Dental orthodontics I II, Dental orthodontics practice I II, and Dental orthodontics & practice III have a meaningful difference. ($\rho$< 0.05 ) 3. In an analysis of the correlation which is based on an age The major basis subjects -Introduction to dental technology, Dental esthetic, and Dental casting procedure-, and the major application subjects -Crown and bridge prosthodontics practice, Complete denture prosthodontics, Dental orthodontics, Dental orthodontics practice, and Operative dentistry laboratory technology- have meaningful difference. ($\rho$< 0.05 ) 4. In a correlation coefficient between subjects; The correlation coefficient of the major application subjects is higher than the major basis subjects. According to the student - t, we found that the level of significance is $\rho$< 0.001, which is meaningful. We feel the lack of a limitation which we didn't survey all students who are major in Department of Dental Technology. And we also feel that we'd better to consider not only students who being in college but also graduated students.

• Maxillofacial Plastic and Reconstructive Surgery
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• 제15권3호
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• pp.229-237
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• 1993

자자는 1991년 2월부터 1993년 2월까지 경북대학교병원 구강악안면외과에 하악전돌 및 개구교합을 주소로 내원하여 하악골 시상골절단술을 이용하여 악교정 수술을 받은 환자중 추적 조사가 가능했던 9명의 개구교합을 동반한 하악 전돌증 환자와 개구교합이 없는 하악 전돌증 환자 9명, 총 18명을 대상으로 두부 상사선 규격사진을 이용한 술후 재발에 관한 연구를 시행하여 다음과 같은 결과를 얻었다. 1. 비개구교합군에 비해 개구교합군에서 술전 전안면고경, 하악 하연 평면각 및 하악 우각부 값이 더 크게 나타났으나 유의성은 없었다.(p>0.05) 2. 개구교합군에서 수술시 SNB 값과 하악 하연 길이의 변화량이 하악의 재발과 통계적으로 유의한 상관 관계가 있었다.(p.<0.01) 3. 개구교합군에서 전안면고경은 술후 비교적 안정되어 있었다. 4. 개구교합군과 비개구교합군에서 수술에 의한 하악 하연 평면각의 변화와 하악의 수평 이동량은 재발과 상관 관계가 없었다.(p>0.01) 5.개구교합을 가진3급 부정교합 환자에서 하악골 시상골 절단술을 시행시 본 연구에서는 수직적 재발보다는 수평적 재발에 문제가 있었다.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• 제27권5호
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• pp.464-467
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• 2001

Aplastic anemia is a hematopoietic disorder characterized by marked reduction or absence of erythoid, granulocytic, and megakariocytic cells in the bone marrow with resultant pancytopenia. To control of infection & bleeding secondary to leukopenia and thrombocytopenia, the inflammatory lesions in oral & maxillofacial area should be removed. Material & Method: The extractions were performed on 21 patients with severe aplastic anemia. The initial, pre-operative and postoperative CBCs were checked up. Amount and kind of transfused platelet in each patient and increment of platelet level were recorded. The complications were documented. Result : A mean of 2.9 teeth were extracted from each patient(ranging between 1 and 13). Furthermore, surgical extractions including ostectomy and odontectomy of the third molar were performed on 11 patients. The preoperative WBC levels presented between $600/{\mu}L$ and $5000/{\mu}L$(mean $2376/{\mu}L$). The WBC values decreased by an average of $145/{\mu}L$ per patient after extractions had been performed. The teeth of 16 patients were extracted under 10.0g/dL, and the mean change in postoperative hemoglobin levels in comparison with preoperative hemoglobin levels was -0.06 per patient. The initial platelet levels were between 1000/(L and $81,000/{\mu}L$(mean $20,174/{\mu}L$). In five patients, extractions were performed with platelet levels less than $50,000/{\mu}L$. Conclusion : The results suggest that more active and preventive treatments in the oral and maxillofacial area are possible and are necessary to remove the infectious foci on the patients with severe aplastic anemia. We report the results of our experiences and literature reviews in treatment of the patients with severe aplastic anemia in our department.

• 대한치과의사협회지
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• 제22권7호통권182호
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• pp.607-620
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• 1984

Mandibular Kinesiograph (MKG-5R)으로부터 얻어지는 자료의 유효성에 관한 연구를 위하여 비철, 비자석성의 기구를 이용해서 3cm×4cm×5cm의 4차원적 입체공간내에서 수행하였다. Kinesiograph로 부터의 직접 얻어지는 자료(관찰치)와 실제 움직인 거리(실제치)간의 관계를 먼저 보기위해 Scatter plot과 Correlation이 연구됐다. 그러나 최종의 목표는 어떤 형태의 공식을 만들어 이것으로 Kinesiograph관찰치를 이용, 실제치를 알도록 하는 것이었으므로 관찰치의 통계학적 회귀분석이 수행되었다. 통계분석의 결과는 Kinesiograph 관찰치와 실제치 간의 강한 상관관계를 보였다. 그러나 높은 상관계수가 반드시 얻어진 선형모형의 완벽한 예측성을 의미하는 것은 아니다. 이 연구로부터 얻어진 선형모형이 실제치를 모두 완벽하게 예측할수는 없었다. 그 이유로서는 종속변수(실제치)의 불연속성과 관찰치(비종속변수) 상호간의 독랩성 때문이다. 결론적으로 Kinesiograph가 어떤 형태로든 적절한 방법에 의해 수정이 있지 않으면 그 계통자체내에 내재하는 비선형적 특성 때문에 그 이용이 하악운동의 제한된 범위내에만 적용될 수 있다.

• 대한치과의사협회지
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• 제22권7호통권182호
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• pp.621-633
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• 1984

Kinesiograph로부터 얻어지는 자료의 선형범위를 확장하고자 하는 연구가 비철, 비자석성의 기구를 사용하여 수행되었다. 자석을 5mm의 일정한 간격으로 자석감지장치가 달린 구조물에 팽팽하게 세평면(frontal, horizontal, sogittal plam)을 통해 3cm×4cm×5cm의 입체공간내에서 693개의 움직여서 만들어지는 자료점으로 항렬 (matrix)을 얻었다. 각각의 자료점에 있어서 Kinesiograph로부터 얻어진 관찰된 값과 움직인 실제값이 상관지어졌다. 따라서 관찰된 값의 세 상관계수를 알게되면 실제값인 세 계수를 얻을수 있게 됐다. 이 업무를 수행하기 위해서 컴퓨터 프로그램이 Fortran을 이용해서 특별히 쓰여졌다. 각 자료점이 5mm 서로 떨어져 있으므로 연구된 입체공간에는 각각 8개의 자료점을 가진 480개의 입방체가 존재한다. 따라서 각각 자료점간에 더 작은 간극을 마련할 수 있다면 보다 더 정밀한 계측이 가능 할 것이다. 결론으로 컴퓨터의 도움으로 기능적 하악운동의 전체범위에 걸친 절대계측들 가능케 하는 이론적 모형이 제시되었다.

• 치과방사선
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• 제23권2호
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• pp.291-299
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• 1993

This study was designed to evaluate the correlationship between radiologic classifications of cysts in oral region and glycosaminoglycan analysis of cystic fluids using cellulose acetate electrophoresis. The materials for this study consisted of 37 cases-8 periapical cysts, 10 dentigerous cysts, 10 primordial cysts, 2 residual cysts, 3 incisive canal cysts, 2 post-operative maxillary cysts, 1 mucocele on maxillary sinus, & 1 unicystic ameloblastoma-diagnosed as cystic lesions radiologically. The obtained results were as follows: 1. At the stepwise discriminant analysis, four variables-low mobility material, heparin, hyaluronic acid, & dermatan sulfate-were used to define diagnostic model for the odotogenic cyst. The model produced a sensitivity of 100% and a specificity of 85%. 2. The intensities of heparin and chondroitin-4-sulfate were greater in dentigerous cyst than periapical cyst(p<0.05). The intensity of chondroitin-4-sulfate was greater in primordial cyst than in periapical cyst(p<0.05). 3. It showed no statistically significant difference in glycosaminoglycan of the cystic fluids between dentigerous cyst and primordial cyst(p>0.05). 4. On the fluids of the cysts originated from maxillary sinus, there were especially high intensities of heparin and dermatan sulfate, and low intensity of chondroitin-4-sulfate. 5. On the fluids of unicystic ameloblastoma, there were high intensity of dermatan sulfate and low intenity of chondroitin-4-sulfate.