• 대한소아치과학회지
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• 제38권1호
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• pp.75-81
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• 2011

치배형성기 발육 이상으로 유치열이나 영구치열에서 정상보다 많이 발생하게 된 치아를 과잉치라 한다. 과잉치는 형태에 따라 정상 치아와 형태가 비슷한 보충치(supplementary tooth)와 형태가 다른 흔적치(rudimentary tooth)로 나눌 수 있다. 대부분의 과잉치는 흔적치의 형태를 가지며 보충치는 드물게 나타난다. 보충치는 상악 측절치 부위에서 호발하며 정상 전치와 유사한 형태와 크기를 갖기 때문에 진단시 특별히 주의를 기울여야 한다. 미맹출 과잉치는 상악 전치의 맹출 장애 및 전위, 치간 이개, 치근 흡수, 낭종 형성 등의 합병증을 유발할 수 있으므로 조기에 진단하고 치아 배열 상태 및 치아 발육 단계에 따라 적절한 치료를 시행하는 것이 중요하다. 본 3 증례는 상악 측절치부에 편측 혹은 양측으로 보충치 형태의 과잉치를 갖는 증례로서 맹출 관찰 및 외과적 발거, 교정 치료 및 레진 수복을 통해 치료하였다.

• Journal of Dental Anesthesia and Pain Medicine
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• 제22권1호
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• pp.1-10
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• 2022

Background: Inferior alveolar nerve block (IANB) is known to have a lower success rate for anesthesia in patients with irreversible pulpitis. This calls for supplementary techniques to effectively anesthetize such patients. This systematic review aimed to evaluate the published literature for determining the success rate of anesthesia induction using post-IANB intraligamentary (IL) injection in the mandibular teeth of patients with symptomatic irreversible pulpitis. The review question was, "What is the success rate of IL injection in the mandibular teeth of patients with irreversible pulpitis as a supplementary technique for endodontic treatment?" Methods: A thorough search of electronic databases and manual searches were performed. The protocol of the review was framed following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) checklist and was registered in the International Prospective Register of Ongoing Systematic Reviews (PROSPERO) with a proper criterion for inclusion and exclusion of studies. The included studies were analyzed using the Cochrane Collaboration "Risk of Bias" tool. A meta-analysis that included a comparison of primary nerve block and supplemental IL injection was performed. The success rate was evaluated using the combined risk ratio (RR) with a random risk model. A funnel plot was created to measure publication bias. Results: After all analyses, four studies were included. In the forest plot representation, RRs were 3.56 (95% CI: 2.86, 4.44), which were in favor of the supplemental IL injections. Statistical heterogeneity was found to be 0%. These values suggest that supplemental IL injections provide better success rates for anesthesia. Conclusion: According to the pooled qualitative and quantitative analyses, supplemental IL injections increased anesthetic efficacy.

• 대한소아치과학회지
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• 제42권2호
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• pp.180-187
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• 2015

색소실조증은 외배엽 이형성증과 같이 다수의 치아결손을 동반하는 선천성 질환으로 Bloch-Sulzberger syndrome이라고 불리며 X 연관 우성 유전질환이므로 주로 여아에서 많이 발병한다. 외배엽 및 중배엽 기원 조직인 피부, 눈, 머리카락, 치아 및 중추신경계에 증상이 나타나며 Xq28 염색체의 NEMO 유전자의 돌연변이에 의해 발병된다. 본 증례는 유치의 선천적 결손을 주소로 내원한 3명의 환아의 증례를 다루고 있으며 이들은 다수의 유치와 영구치의 선천적 결손, 전치부 원뿔형 치관, 구치부 과잉 교두 등을 보이고 있었다. 치아결손부에 공간 유지 장치를 장착하여 저작기능을 회복해 주고 심미적인 문제를 개선해주었으며 계속적인 관찰이 필요하다.

• 한국치위생학회지
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• 제13권5호
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• pp.881-888
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• 2013

Objectives : The purpose of the study is to investigate the risk factors of dental caries in early childhood. Methods : Subjects were 197 mothers having 5 year old children. They completed the questionnaire from June 1 to July 14, 2012. Results : At birth, the age of mother and the number of teeth experiencing dental caries showed high correlation(r=0.163, p<0.05). Early beginning(r=-0.441, p<0.05) and long period(r=0.441, p<0.05) of mix feeding were closely related to dental caries outbreak. Long period of supplementary food caused deciduous dental caries (r=0.643, p<0.001) and dental caries experience (r=0.723, p<0.001). Long period of breast feeding (r=0.261, p<0.001) also caused deciduous dental caries. Low BMI of mother was colsely related to high dental caries(r=-0.206, p<0.01). Deciduous dental caries accounted for 61.8% and the number of teeth experiencing dental caries was 68.5%. Conclusions : Appropriate breast feeding habit is the most important behavior of preventing deciduous dental caries in 5 year old children.

• 동력기계공학회지
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• 제13권6호
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• pp.102-109
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• 2009

A retarder, as a supplementary brake system that is not friction-based, is frequently used in heavy-duty vehicles generally to slow the vehicles down on inclines. The electric retarder mainly used in a heavy-duty bus is generally placed between the transmission and the axle. The rotor inside the retarder system is attached to the axle. The operation of the retarder within a driven vehicle generates reverse torque due to coast driving force on hypoid gears in the differential gear system. By the reverse torque, scoring or scuffing on the hypoid gear teeth may directly occur. The scoring may be generated due to excessive contact stresses on the tooth surface. In this study, tooth contact stresses and contact patterns were analysed in order to investigate on the tooth scoring phenomenon using a finite element analysis program T900 in which the Hertzian contact stress formula was taken. Backlash, wear and surface finish were considered in the finite element simulation on the scoring.

• Journal of Biosystems Engineering
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• 제42권4호
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• pp.242-250
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• 2017

Purpose: This study was conducted to determine the appropriate operating conditions through a factorial experiment for the secondary separating part of the self-propelled pepper harvester. Methods: An experimental setup that simulates the secondary separating part of the self-propelled pepper harvester was organized. Test samples were classified into three types according to the number of peppers on a stem, and 12 sets were prepared for each type. Among the operating conditions of the secondary separating part, the rotational speed of drum B (four levels), radial clearance between drums and cylindrical teeth (three levels), and speed ratio between the three drums (two levels) were set as the test factors, and tests were repeated three times for different levels of each factor. The appropriate operating conditions were determined by analyzing the separation ratio and damage ratio of the peppers collected through the secondary separating part. Results: The test factors changed the overall separation ratio and overall damage ratio in similar trends. In other words, the conditions that caused high overall separation ratios also exhibited high overall damage ratios. Owing to the high overall damage ratio in the condition with the highest overall separation ratio, the operating conditions should be selected considering both ratios. Conclusions: When the condition with more than 60% of overall separation ratio and less than 15% of overall damage ratio was considered as the appropriate operating condition, 70 rpm of the rotational speed of drum B, 5 mm of the radial clearance between drums and cylindrical teeth, and 7:3:5 for the speed ratio of the three drums A, B, and C should be applied for the secondary separating part used in this study. Supplementary studies will be required in the future to find optimal operating conditions through the actual field test under further divided test factors.

• 대한치과의사협회지
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• 제54권7호
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• pp.563-574
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• 2016

A clear overlay appliance is a type of a removable appliance made from transparent thermoplastic plastic film that covers the entire dentition to move the teeth. It is one of the most favored orthodontic methods opted for by adult patients; this treatment is esthetic, does not cause discomfort and allows oral hygiene to be easily managed when compared to other conventional fixed treatment methods. However, the use of clear overlay appliances, such as invisalign or clear aligner, is associated with various clinical challenges. In particular, the appliances require longer treatment periods compared to fixed treatment, and due to the structural characteristics of the appliances, it is difficult to make proper posterior occlusion and certain type of tooth movement, including extrusion, rotation and tip. Thus, the clear overlay appliances are regarded as supplementary appliances by most orthodontists and have been used for simple orthodontic treatments, such as partial anterior alignments or orthodontic relapse cases. Owing to the remarkable advancement in the field of 3D digital technology over a period of 15 years, the accuracy and convenience of modern clear overlay appliances have continuously improved. Moreover, orthodontic outcomes have also been greatly improved by the introduction of new materials and successful application of various biomechanical methods from conventional orthodontic treatments in the design of clear overlay appliances. This study investigates the clinical limitations that should be considered during the application of clear overlay appliances and also examines the efforts and methods used to overcome these challenges.

• 대한치과기공학회지
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• 제36권3호
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• pp.205-217
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• 2014

Purpose: This study will examine the differences among the college dental morphology textbooks in light of their contents and learning objectives through which we will propose an optimal way of consolidating those differences found. Methods: Five college textbooks adopted in the dental related departments were selected by random and the overview and subdivisions of contents were compared and closely analysed with regards to the learning objectives. Results: Firstly, all of the dental morphology textbooks cover the learning objectives of the dental morphology subject, especially in the area of the overview of dental morphology, the permanent tooth, deciduous tooth. Only the dentistry textbooks explain the learning objective of the occlusion. Secondly, differences in content were found in the area of component tissue and around tissue, dental formula of deciduous teeth, spinous process, buccal pit, enamel projection, curve symbol, tip of cusp position of proximal surface of permanent mandibular canines, buccal cusp position of permanent mandibular second premolars. Conclusion: It is imperative to delineate some meaningful and critical differences in contents among the dental morphology textbooks and reflect this to each and every textbook to be published as a supplementary information guide or index.

• 치위생과학회지
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• 제7권3호
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• pp.129-133
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• 2007

본 연구는 현재 서울에 소재하고 있는 S보건대학 치위생과 학생들을 대상으로 인위적인 구취를 발생시킨 후 실험 전, 양파즙 가글 직 후, 실험 5분, 실험 10분, 실험 20분, 실험 30분경과에 따른 구취도를 측정하였다. 실험대상을 잇솔질만 시행한 실험군 (실험군 A), 보조용품만 시행한 실험군 (실험군 B), 어떤 보조용품도 사용치 않은 상태에서의 경과시간에 따른 구취도를 측정한 실험군 (실험군 C)으로 분류하였다. 또한 보조용품군을 가글액 사용군, 껌 저작군, 현미녹차 섭취군, 혀솔질군 등으로 나누어 잇솔질을 대처할 수 있는 최적의 구강보조용품이 어떤 것인가에 대하여 연구하고자 하였다. 1. 실험군 A와 실험군 BG의 경과시간에 따른 구취도의 변화는 실험 30분 경과부터 유의한 차이를 보였다 (p < 0.05). 2. 실험군 A와 실험군 BC의 경과시간에 따른 구취도의 변화는 실험 20분 경과부터 유의한 차이를 보였다 (p < 0.05). 3. 실험군 A와 실험군 BT의 경과시간에 따른 구취도는 실험 20분 경과부터 유의한 차이를 보였다 (p < 0.05). 4. 실험군 A와 실험군 BO의 경과시간에 따른 구취도의 변화는 실험 전에서 실험 30분 경과까지 유의한 차이를 보이지 않았다 (p > 0.05). 5. 실험군 C는 실험군 A, B,군에 비하여 아주 높은 수치를 보이며 실험 30분 경과까지 구취도가 감소하였다. 본 연구의 실험 결과 잇솔질을 시행하지 못한 경우 가그린, 껌 저작, 현미녹차섭취, 혀 긁겅이 중에서 가그린의 사용이 구취감소에 가장 효과적이였다.

• Restorative Dentistry and Endodontics
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• 제46권2호
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• pp.17.1-17.9
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• 2021

Objectives: In recent in vitro study, it was reported that osteostatin (OST) has an odontogenic effect and synergistic effect with mineral trioxide aggregate (MTA) in human dental pulp cells. Therefore, the aim of this study was to evaluate whether OST has a synergistic effect with MTA on hard tissue formation in vivo. Materials and Methods: Thirty-two maxillary molars of Spraque-Dawley rats were used in this study. An occlusal cavity was prepared and the exposed pulps were randomly divided into 3 groups: group 1 (control; ProRoot MTA), group 2 (OST 100 μM + ProRoot MTA), group 3 (OST 10 mM + ProRoot MTA). Exposed pulps were capped with each material and cavities were restored with resin modified glass ionomer. The animals were sacrificed after 4 weeks. All harvested teeth were scanned with micro-computed tomography (CT). The samples were prepared and hard tissue formation was evaluated histologically. For immunohistochemical analysis, the specimens were sectioned and incubated with primary antibodies against dentin sialoprotein (DSP). Results: In the micro-CT analysis, it is revealed that OST with ProRoot MTA groups showed more mineralized bridge than the control (p < 0.05). In the H&E staining, it is showed that more quantity of the mineralized dentin bridge was formed in the OST with ProRoot MTA group compared to the control (p < 0.05). In all groups, DSP was expressed in newly formed reparative dentin area. Conclusions: OST can be a supplementary pulp capping material when used with MTA to make synergistic effect in hard tissue formation.