• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2000년도 추계학술대회 논문집
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• pp.810-813
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• 2000

Burr makes trobles on manufacturing process due to deburring cost, quality of products and productivity. This paper described the results of experimental study on the influence of the cutting parameters on the formation of exit burrs in face milling. The cutting parameters were investigated changing exit angle, rake nagle , lead angle in tool geometry as well as feed per tooth. Also we carried out experimets on several materials. Using the result of experimental study, burr types are classified according to appearance and formation mechanism in exit burr and we are considered the burr formation in each type of burr.

• 대한치과의사협회지
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• 제50권6호
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• pp.322-328
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• 2012

Ectopic eruption of the permanent first molar is defined as the eruption of the tooth in an abnormal position or orientation. It may causes distal root resorption and premature exfoliation of the adjacent primary second molar and uncontrolled space loss is followed. Prolonged partial impaction of the permanent molar may also cause undetected caries or abscess formation of the neighbor teeth. The purpose of this paper is to provide a brief review regarding the etiology, classification, and different management techniques for correcting ectopic eruption of permanent first molar.

• 치과방사선
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• 제15권1호
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• pp.21-26
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• 1985

The author observed 97 cases ameloblastoma diagnosed in Department of Oral Radiology in Seoul National University and analyzed patient's age, sex, location, relation with adjacent anatomic structures, and radiographic forms. The obtained results are as follows: 1. The average age of patients was 28.7 years. The mean age of male was 28.5 years, and female's 30.0 years. Third decades revealed highest rate. 2. The occurrence of ameloblastoma is approximately evenly distributed in both sexes, male 46 cases (47.2%), female 51 cases (52.6%). 3. Ninty-five (98.0%) cases occurred in the mandible. The mandibular molar-ramus region was the most frequent site of the tumor (74 cases, 76.3%). 4. Most of the cases affected adjacent anatomic structures. 24 cases (24.7%) were shown to be definitely associated with an impacted tooth. 5. Radiographic forms are unilocular (29 cases, 29.3%), honeycomb (17 cases, 17.5%), and multilocular (67 cases, 69.1%) radiolucencies.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• 제46권5호
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• pp.328-334
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• 2020

Objectives: This study aimed to validate the effectiveness of a recently proposed difficulty index for removal of impacted mandibular third molars based on extraction time and suggest a modified difficulty index including the presence of pathologic conditions associated with third molars. Materials and Methods: This retrospective study enrolled 65 male patients younger than 25 years with third molars. Extraction time was calculated from start of the incision to the last suture. The difficulty scores for third molars were based on spatial relationship (1-5 points), depth (1-4 points), and ramus relationship (1-3 points) using cone-beam computed tomography. The difficulty index was defined as follows: I (3-4 points), II (5-7 points), III (8-10 points), and IV (11-12 points). The modified difficulty score was calculated by adding one point to the difficulty score if the third molar was associated with a pathologic condition. Two modified difficulty indices, based on the presence of pathologic conditions, were as follows: the half-level up difficulty index (HDI) and the one-level up difficulty index (ODI) from the recently proposed difficulty index. Results: The correlations between extraction time and difficulty index and or modified difficulty indices were significant (P<0.001). The correlation coefficient between extraction time and difficulty index was 0.584. The correlation coefficients between extraction time and HDI and ODI were 0.728 and 0.764, respectively. Conclusion: Extraction time of impacted third molars exhibited a moderate correlation with difficulty index and was strongly correlated with the modified indices. Considering the clinical implications, the difficulty index of surgical extraction should take into consideration the pathologic conditions associated with third molars.

• 대한장애인치과학회지
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• 제14권2호
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• pp.102-105
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• 2018

중등도의 혈우병 A 환아와 중증의 혈우병 B 환아가 응고인자 투여 후 전신마취 하에 각각 매복 과잉치 발거술 및 다수 유치의 우식치료를 받았다. 이와 같이 혈우병 환자의 치과치료 시에는 부족한 응고인자를 보충해주는 등의 응고인자 수준의 관리와 복잡한 의과적 처치 및 술 후 관리가 요구된다. 또한 치과치료 시 출혈을 유발되지 않도록 주의해야 하며 응급 상황 등에 대비하여 국소적 지혈 방법 등을 숙지하고 있는 것이 필요하다.

• Journal of Periodontal and Implant Science
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• 제53권2호
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• pp.135-144
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• 2023

Purpose: The aim of this study was to investigate the risk of periodontitis according to current smoking status based on the number of cigarettes smoked per day (CPD) and the Fagerström Test for Nicotine Dependence (FTND). Methods: All enrolled patients were diagnosed and classified according to the new periodontal classification scheme, and current smoking status was investigated via a self-reported questionnaire. The correlation between smoking status (CPD and FTND) and periodontitis risk (severity of periodontitis and tooth loss due to periodontal reasons) was statistically assessed using Spearman correlation coefficients. Moreover, partial correlation analyses between smoking and periodontal status were performed after adjusting for age, sex, and diabetes mellitus. Results: Overall, data from 74 men and 16 women (mean age: 48.1±10.8 years) were evaluated. The mean number of missing teeth, CPD, and FTND score were 3.5±5.2, 24.6±15.5, and 3.5±2, respectively. CPD and the FTND were significantly positively correlated with each other (r=0.741, P<0.001). CPD and the FTND were also significantly correlated with the severity of periodontitis (CPD: r=0.457, P<0.05 and FTND: r=0.326, P<0.05) and the number of missing teeth due to periodontal reasons (CPD: r=0.525, P<0.05 and FTND: r=0.480, P<0.05), respectively. Conclusions: Within the limitations of this study, both CPD and the FTND were significantly correlated with the severity of periodontitis and the number of periodontally compromised extracted teeth.

• 대한치과교정학회지
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• 제35권1호
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• pp.15-22
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• 2005

본 연구의 목적은 한국인 부정교합자에서 하악 치열궁간의 형태적 차이를 알아보고자 하였다. I급 114명, II급 119명, III급 135명의 부정교합자를 대상으로 하악 모형의 교합면을 복사한 후 13개의 접촉점 중에서 가장 협측면으로 위치한 부분을 digitize 하였고 각 치아의 브라켓 위치에 해당하는 점을 하악치아의 두께에 의거하여 4개의 선계측과 2개의 비율을 측정하였다. 치열궁의 형태는 square ovoid tapered형으로 분류하여 그 빈도를 조사한 결과 Angle 분류와 남녀 성별에 따른 특별한 치열궁 형태가 존재하지 않았으나 특정 치열궁 형태의 빈도는 Angle 분류에 따라 다르게 나타났다. 치열궁 크기의 계측항목에서는 대구치간 폭경에서만 남녀 성별 차이를 보였으며, 치열궁 크기에 있어서 I급과 III급. II급 부정교합군간에는 유의한 차이가 있었다 치열궁 형태의 분포는 I급과 III급 부정교합군에서는 square ovoid, tapered 형태 순이었고. II급 부정교합군은 square, tapered ovoid 형태 순이었다 치열궁 형태의 빈도분포에 있어서는 남녀간의 차이는 없었다.

• 한국치위생학회지
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• 제11권6호
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• pp.923-938
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• 2011

Objectives : This study was attempted in order to grasp oral health level according to socio-demographic characteristics in elders in some communities, and to evaluate oral health status and its association. Methods : The subjects in this study were performed with 235 people, who were over 65 years and resided in Daejeon Province, from June 20 to July 10, 2011. An individual interview was held, and they got a dental checkup. As for data analysis, chi-square test, t-test, one-way ANOVA, pearson correlation were utilized. Methods : The subjects in this study were performed with 235 people, who were over 65 years and resided in Daejeon Province, from June 20 to July 10, 2011. An individual interview was held, and they got a dental checkup. As for data analysis, chi-square test, t-test, one-way ANOVA, pearson correlation were utilized. Results : The older age in the whole research subjects and the lower educational level led to the less remaining teeth and the larger missing teeth index. The decayed missing filled teeth index and the decayed missing filled teeth rate were higher in more women and older age and in the lower educational level. Tooth mortality rate was higher in the older age, the lower educational level, and the group of living together with spouse. The maxillary-mandibular fixed-bridge status in the mouth was indicated to be the highest in the full-denture mounting ratio as for elders in over 80 years old. Oral Health Impact Profile(OHIP-14) average score was $56.05{\pm}11.64$ in the whole research subjects The decayed missing filled teeth index and the decayed missing filled teeth rate showed significantly positive correlation with the decayed missing filled teeth rate, tooth mortality rate and showed significantly negative correlation with OHIP-14. Tooth mortality rate showed significantly negative correlation with OHIP-14 Oral Health Impact Profile(OHIP-14) showed significantly positive correlation with its factors. Conclusions : Accordingly, the policy effort is considered to be necessary that implements in elders in order to spend active senescence, and that elders' health and oral-health behavior can be implemented continuously and preventively through classification according to elders' physical function.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• 제32권6호
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• pp.588-593
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• 2006

Cyst is pathologic disease develops in hard tissue as well as soft tissue, which is lined by epithelium filled with liquid, semi-liquid, or air. Origins and symptoms of the cyst are various according to region, and symptoms are malocclusion, diversion of root, tooth mobility, periapical swelling, discoloration and lesion expansion, because the odontogenic cysts begin in the numerous rests of odontogenic epithelium. But almost cysts produce no symptoms unless secondary infection occurs. Treatment of small cysts may include extraction, endodontic therapy, and apical surgery. Treatment of a large cysts usually involves surgical removal (enucleation), Marsupialization(a method of decompression) or combination of two before mentioned. Bone graft is done for helping of bone defect healing at the same time of enucleation This clinical research from January 2000 to December 2005, analyzed by the age, sex, classification, size, region, treatment method, whether or not of bone graft of cyst in the jaw in Daegu Catholic University Hospital.

• Imaging Science in Dentistry
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• 제51권1호
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• pp.9-16
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• 2021

Purpose: The purpose of this study was to analyze the reliability of 7 panoramic radiographic signs for predicting proximity of the root apices of mandibular third molars to the mandibular canal using cone-beam computed tomography and to correlate these findings with the Pell and Gregory and the Winter classification systems. Materials and Methods: An observational, cross-sectional, descriptive study was conducted on 74 patients with bilateral impacted mandibular third molars. Four panoramic radiographic signs were observed in the tooth root (darkening, deflection, and narrowing of the root apices, and bifid apices), and another 3 in the mandibular canal (diversion, narrowing, and interruption of the mandibular canal). Cone-beam computed tomography images were analyzed to identify disruption and diversion of the mandibular canal and root deflection. Results: Binary logistic regression showed that only 4 of the 7 panoramic radiographic signs were able to predict proximity of the root apices of the mandibular third molars to the mandibular canal: darkening of the root, deflection of the root, narrowing of the root, and interruption of the mandibular canal(P<0.05). Conclusion: Darkening, deflection, and narrowing of the root, in tandem with the interruption of the mandibular canal on panoramic radiographs, indicate that cone-beam computed tomography should be performed when planning the extraction of impacted mandibular third molars. Proximity between mandibular third molars and the mandibular canal is correlated with the Winter classification.