• 대한치과보철학회지
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• 제38권3호
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• pp.366-374
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• 2000

FRC/ceromer system provides the clinician with a durable, flexible, and esthetic alternative to conventional porcelain fused to metal crowns. FRC is the matrix which is silica-coated and embedded in a resin matrix. The ceromer material which is a second generation indirect composite resin contains silanized, microhybrid inorganic fillers embedded in a light-curing organic matrix. FRC/ceromer restoration has a several advantages: better shock absorption, less wear of occluding teeth, translucency, color stability, bonding ability to dental hard tissues, and resiliency. It has versatility of use including inlay, onlay, single crown, and esthetic veneers. With adhesive technique, it can be used for single tooth replacement in forms of inlay adhesion bridge. In single tooth missing case, conventional PFM bridge has been used for esthetic restoration. However, this restoration has several disadvantages such as high cost, potential framework distortion during fabrication, and difficulty in repairing fractures. Inlay adhesion bridge with FRC/ceromer would be a good alternative treatment plan. This article describes a cases restored with Targis/Vectris inlay adhesion bridge. Tooth preparation guide, fabrication procedure, and cementation procedure of this system will be dealt. The strength/weakness of this restoration will be mentioned, also. If it has been used appropriately in carefully selected case, it can satisfy not only dentist's demand of sparing dental hard tissue but also patient's desire of seeking a esthetic restorations with a natural appearance.

• Restorative Dentistry and Endodontics
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• 제7권1호
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• pp.59-63
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• 1981

Ninety four human mandibular third molars were chosen to study the anatomy of the root canal. The experimental teeth were injected with china ink, decalcified, cleared and used in study, in vitro, to determine the number of root, the number of root canals, canals per root, frequency and location of transverse anastomoses, frequency and location of lateral canals and frequency of the apical deltas. The results were as follows: 1. Most of the teeth showed two canals, but 17.0% of the teeth were found to have one canal, 17.0% of them three canals, 3.2% of them four canals and l.1% of them five canals. 2. In so far as observing one canal per root, 17.0% of the teeth were found to have one canal in single-rooted tooth, 48.9% of them in mesial root and 58.5% of them in distal root. 3. In roots with two or three canals, the separated apical foramen appeared in 55.6% in single-rooted tooth, 64.3% in mesial side and 80.0% in distal side, and the common apical foramen appeared in 44.4% in single-rooted tooth, 35.7% in mesial side and 20.0% in distal side. 4. Of the two root canals in one root, 19.1% of the canals were found to have transverse anastomoses and were usually located in the apical third of the root. 5. 63.8% of 94 teeth were found to have lateral canals, and ramifications were mainly located in the apical third of the root.

• Journal of Periodontal and Implant Science
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• 제36권4호
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• pp.925-938
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• 2006

The aim of this study was to systematically investigate the complications of single implant-supported restorations followed more than 5-year. Thirty-five studies were selected for the systematic review. A total of 3932 single implants were included at the beginning of studies. Thirty-one implants were removed before loading and 91 implants after loading. The overall implant loss rate was 3.1 %. Implant losses were concentrated on the period between loading and 2-year follow-up, and, after a stable period, increased after 5-year follow-up. The mean marginal bone loss at single-tooth implants was well within 0.2 mm/year, i.e., acceptable annual bone loss by the implant success criteria. However, considerable amounts of single implants suffered a marginal bone loss at implant more than 0.2 mm/year. Fistula was a frequent biological complication in the early studies. The most frequent technical problem was a screw loosening, but its frequency was reduced after the use of a gold screw and torque controller. Within the limits of this study, the complications of single implants might be underestimated due to the lack of information about the biological and technical complications available in the relevant literature.

• 치위생과학회지
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• 제21권3호
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• pp.185-197
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• 2021

Background: This study aimed at investigating the meal regularity, health, and oral health habits of single Korean households to understand the impact of these factors on the risk of metabolic syndrome, in addition to preventing and managing metabolic syndrome. Methods: Using raw data from the 8th Korea National Health and Nutrition Examination Survey (2019), 274 study subjects, aged 19 to 64, were selected primarily from single adult households. Complex sample statistical analysis was performed using the Predictive Analytics Software Statistics ver. 18.0 program. Results: Regarding the meal regularity in single-person households in Korea, the younger group outperformed the middle-aged group, and those who drank more than once a month performed better than those who drank less than once a month. In terms of oral health, regardless of the age and the income level, participants who ate three meals a day had a higher rate of speech problems and chewing difficulties than those who ate irregularly or regularly on a regular day. Factors influencing the risk of developing metabolic syndrome were age, speech problems, and frequency of toothbrushing. Compared to the younger group, there were 0.361 times more people in the middle-aged group; and compared to those without speech problems, there were 1.161 more people with speech problem. Compared to those who tooth brushed more than four times a day, there were 1.284 more people who tooth brushed 2 to 3 times a day and there were 5.673 times more people who tooth brushed less than once. Conclusion: Based on the study results, it is necessary to implement a program that can plan and apply customized management measures and prevent metabolic syndrome by improving and correcting the health and oral health behaviors of single-person households in Korea. Therefore, active mediation measures, such as support and publicity at the local or national level, should be planned.

• Journal of Mechanical Science and Technology
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• 제17권3호
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• pp.321-328
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• 2003

The elongation of contact length on the line of action is considered with particular reference for roll forming of gears, and for dynamic behavior of the tooth in meshing. However there is no paper that discuss the elongation of contact length in the load meshing of gears. Based on our investigation, the contact length on the line of action elongates more than the kinematically calculated value. In rolling, as the tool approaches the workpiece, the center distance of the gears decreases by a small amount. But, the elongation of contact length is sensitive. Therefore, the contact point on the line of action is difficult to be determined, which complicates the tooth analysis. In this study, the exact relation between the elongation of contact length and the tooth space over the recess or before the approach are revealed by experiments and kinematic theory. This analytical result applies not only for rolling, but also for the single flank meshing which is done under constant center distance.

• Imaging Science in Dentistry
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• 제43권2호
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• pp.123-128
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• 2013

Double tooth is a dental anomaly consequent to fusion of two or more teeth or gemination of a single tooth. This report describes a unique case of double tooth in relation to a mandibular lateral incisor exhibiting the presence of four root canals. The role of conventional radiography and advanced three-dimensional imaging techniques in the better assessment of complex root canal systems and their aid in endodontic management has also been highlighted.

• 대한치과의사협회지
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• 제51권3호
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• pp.138-147
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• 2013

Orthodontic tooth movement is a unique process which tooth, solid material is moving into hard tissue, bone. Orthodontic force in general provides the strain to the PDL and alveolar bone, which in turn generates the interstitial fluid flow(in detail, fluid flow in PDL and canaliculi). As a results of matrix strain, periodontal ligament cells and bone cells are deformed, releasing variety of cytokines, chemokines, and growth factors. These molecules lead to the orthodontic tooth movement(OTM). In these inflammation and tissue remodeling sites, all of the cells could closely communicate with one another, flowing the information for tissue remodeling. To accelerate the rate of OTM in future, local injection of single growth factor(GF) or a combination of multiple GFs in the periodontal tissues might intervene to stimulate the rate of OTM. Corticotomy is effective and safe to accelerate OTM.

• 구강회복응용과학지
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• 제25권3호
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• pp.267-277
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• 2009

구강 내 단일 치아를 상실한 경우 기존에는 고정성 보철물을 이용하여 수복하는 방법이 일반적이었지만, 최근에 와서는 임플란트를 이용하여 수복하는 것이 보편화되고 있다. 본 연구는 단일 치아 결손 시 $TiUnite^{TM}$ 표면 처리한 임플란트를 이용하여 수복한 경우를 후향적으로 조사하여 그 생존율을 분석한 것이다. 2002년 9월부터 2006년 12월까지 삼성서울병원에서 단일 치아 결손 부위에 식립된 총 269개의 $TiUnite^{TM}$ 표면 처리한 임플란트 중 21개는 인접한 임플란트가 있거나, 기록이 누락되거나 관찰 기간이 짧아 연구에서 제외되었다. 248개의 임플란트 중 상악에는 129개(52.0%) 하악에는 119개(48.0%) 식립되었다. 수술 부위에 치조골 재생술을 시행한 경우는 총 100개(40.3%)였으며, 상악동 거상술이 시행된 증례는 총 36개(14.5%)였다. 수술 당일부터 관찰 기간은 평균 $26.0{\pm}11.8$ 개월이었으며, 그 기간 동안 실패한 것으로 간주된 임플란트는 12개로 생존율은 95.2%였다. 그 중 상악에서 실패한 경우가 10개, 하악에서는 2개로 각각의 생존율은 92.2%, 98.3% 이다. 단일 치아 결손 시 $TiUnite^{TM}$ 표면 처리한 임플란트를 이용하여 수복한 경우 단기간 동안 높은 생존율을 보였다.

• 대한치과교정학회지
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• 제18권1호
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• pp.227-234
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• 1988

To study diagnosis and treatment plan of malocclusion, comparison of race and nation and consideration of treatment technique, 885 orthodontic patients of the department of orthodontics, Infirmary of dental college, Chosun University were evaluated. The frequency and pattern of tooth extraction were studied according to malocclusion types and developmental stages of occlusion and sex. Thefollowingresultswereobtained. 1. Average frequency of tooth extraction for orthodontic treatment was $38.3\%$. 2. The frequency of tooth extraction was $43.7\%$ in class I malocclusion, $34.2\%$ in class II malocclusion and $32.1\%$ in class III malocclusion. 3. The drequency of tooth extraction was the highest in permanent dentition $(49.2\%)$. 4. The frequency of tooth extraction was not different between male and female. 5. The frequency of 3-4 premolars extraction was the highest $(57.5\%)$ and that of lower incisor extraction was the lowest $(2.9\%)$ in patterns of tooth extraction. 6. Both frequency of unilateral and single arch extraction were the highest in class III malocclusion.

• 대한치과기공학회지
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• 제42권4호
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• pp.313-320
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• 2020

Purpose: The purpose of this study is to compare and analyze the accuracy of single crowns based on the type of occlusal surface. Methods: A single crown wax pattern was fabricated in three types of occlusal surface. The prepared wax pattern was replicated with silicone, and stone was injected to create a stone model. The prepared specimens were scanned using a model scanner. Scans were classified into three groups, and each scan was performed six times to analyze the trueness and precision of a single crown. In addition, only the occlusal surface area was analyzed for trueness and precision. Data were analyzed using the Kruskal-Wallis H test, a nonparametric test (α=0.05). Results: With regard to the trueness value of the occlusal scan area, the no occlusal tooth attrition (NA) group showed the largest error of 3.5 ㎛, and the complete occlusal tooth attrition (CA) group showed the lowest value of 3.1 ㎛. The NA group had the greatest precision, and the medium occlusal tooth attrition (MA) group and CA group showed a low precision value of 3.2 ㎛; the difference between the groups was statistically significant (α=0.05). In the color difference map, the CA group showed a lower error than the NA group. Conclusion: The occlusal surface with severe attrition had excellent accuracy, but the accuracy of the group without attrition was low. There were significant differences between groups, but clinically acceptable values were shown.