• 대한간호학회지
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• 제38권6호
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• pp.914-922
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• 2008

Purpose: To examine the effect of tooth-brushing education on the oral health of preschoolers. Methods: A quasi-experimental design with a non-equivalent control group was used. Two kindergartens were selected and 39 preschoolers from one kindergarten were assigned to the experimental group with tooth-brushing education and 39 from the other kindergarten to the control group. The tooth-brushing education program included 1 session on oral health education, individual tooth-brushing instruction for 1 week and supervised tooth-brushing after lunch for 4 weeks. Oral health behavior including use of tooth paste, tooth-brushing time and method of tooth-brushing, plague, streptococcus mutans, lactobacillus and dental caries were measured before and after the education. Fisher's exact test, t-test and paired t-test with the Window SAS 9.1 program were used to analyze the data. Results: A significant increase in the use of tooth paste, tooth-brushing time and the practice of correct tooth-brushing and a decrease in plague and development of dental caries were observed in the experimental group. Conclusion: This tooth-brushing education was partially effective in improving oral health of preschoolers.

• 대한치과의사협회지
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• 제52권2호
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• pp.75-84
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• 2014

During dental treatment, if a tooth were fractured suddenly by unnoticed tooth crack or vertical root fracture, it would be very embarrassing and frustrating experiences to dentists. But if it were once diagnosed as one of these teeth fracture, dentist should know about the etiology, course of fracture development, treatment modality to avoid argument with patient. In here cases and diagnostic skills, etiology and treatement methods of tooth fracture originated by internal stress and masticatory force were discussed to help dentists.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• 제39권3호
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• pp.103-111
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• 2013

With successful extraction of growth factors and bone morphogenic proteins (BMPs) from mammalian teeth, many researchers have supported development of a bone substitute using tooth-derived substances. Some studies have also expanded the potential use of teeth as a carrier for growth factors and stem cells. A broad overview of the published findings with regard to tooth-derived regenerative tissue engineering technique is outlined. Considering more than 100 published papers, our team has developed the protocols and techniques for processing of bone graft material using extracted teeth. Based on current studies and studies that will be needed in the future, we can anticipate development of scaffolds, homogenous and xenogenous tooth bone grafts, and dental restorative materials using extracted teeth.

• 대한치과의사협회지
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• 제52권5호
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• pp.281-290
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• 2014

Tooth eruption disturbance is seen commonly in mixed dentition or early permanent dentition. During this period of time, children experience the growth and development of craniofacial skeleton and dentition, so the impaction and eruption disturbance of permanent teeth make many problems in oral and maxillofacial areas. Eruption guidance of impacted tooth is not simple because many factors related to impaction are considered. Several factors such as etiology, tooth development stage, location of impacted teeth or eruption pathway, patient cooperation, etc. need to be taken into consideration in deciding the management of the impacted tooth. In the present study, it was assessed the etiology and impaction status of impacted tooth through various cases, and try to explain the treatment method to guide eruption by surgical exposure.

• 대한소아치과학회지
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• 제5권1호
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• pp.7-11
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• 1978

Of 633 children, 334 in male and 299 in female, whose ages ranged from 3 to 13 years old, the amounts of development of teeth germ were observed according to ages with oblique lateral cephalogram to study the developing state of teeth germ of mandibular premolars. The results were as followings; 1. The time of actively develop:ng tooth germ was observed about 10 years old both in male and in female. 2. The increasing rate of development of tooth germ a year was higher in female than in male at mandibular 1st premolar and in male than in female at mandibular 2nd premolar. 3. Age of complete tooth germ development was earlier in female than in male at mandibular 1st and 2nd premolars.

• 대한소아치과학회지
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• 제45권4호
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• pp.484-491
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• 2018

선천적 치아의 결손은 비교적 흔한 치아 발육장애이며 하악 제2소구치의 결손은 치아 결손 중 가장 많이 나타나는 것으로 알려져 있다. 이 연구의 목적은 하악 제2소구치 결손과 연관되어 나타나는 다른 치아의 결손 및 치아의 발육 지연에 대해 조사하는 것이다. 이 연구는 2014년부터 2016년까지 연세대학교 치과대학을 내원하여 파노라마 방사선을 찍은 만 9세-15세의 소아청소년 중 하악 제2소구치 결손이 있는 환자를 대상으로 시행되었다. 하악 제2소구치의 결손을 가진 125명의 환자들 중 다른 치아의 결손은 58명(46.4%)에서 나타났으며 발육이 지연된 치아는 38명(30.4%)에서 나타났다. 이번 연구에서 하악 제2소구치의 결손을 가진 환자는 그렇지 않은 어린이와 비교하였을 때 치아 결손 및 치아 발육지연의 유병률이 높게 나타났다.

• International Journal of Oral Biology
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• 제36권1호
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• pp.31-35
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• 2011

Teeth develop via a reciprocal induction between the ectomesenchyme originating from the neural crest and the ectodermal epithelium. During complete formation of the tooth morphology and structure, many cells proliferate, differentiate, and can be replaced with other structures. Apoptosis is a type of genetically-controlled cell death and a biological process arising at the cellular level during development. To determine if apoptosis is an effective mechanism for eliminating cells during tooth development, this process was examined in the rat mandible including the developing molar teeth using the transferase-mediated dUTP-biotin nick labeling (TUNEL) method. The tooth germ of the mandibular first molar in the postnatal rat showed a variety of morphological appearances from the bell stage to the crown stage. Strong TUNEL-positive reactivity was observed in the ameloblasts and cells of the stellate reticulum. Odontoblasts near the prospective cusp area also showed a TUNEL positive reaction and several cells in the dental papilla, which are the forming pulp, were also stained intensively in this assay. Our results thus show that apoptosis may take place not only in epithelial-derived dental organs but also in the mesenchyme-derived dental papilla. Hence, apoptosis may be an essential biological process in tooth development.

• Applied Microscopy
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• 제46권1호
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• pp.58-66
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• 2016

Thymosin ${\beta}4$ ($T{\beta}4$) has been recently reported to play a role in dentinogenesis by regulating the expression of dentin matrix proteins. Based on previous studies, it is hypothesized that $T{\beta}4$ is associated with the formation of the enamel matrix and thus plays an important role in ameloblast. However, there is no report on the function of $T{\beta}4$ during tooth development so far. Therefore, in this study, we aimed to investigate the expression of $T{\beta}4$ and its function in ameloblasts during mouse tooth development. $T{\beta}4$ was expressed strongly in the tooth bud at the bud stage and in the dental lamina and oral epithelium at the cap stage. In advanced bell stage at postnatal day 4, large elongated ameloblasts were observed and the expression of the $T{\beta}4$ protein was the highest, with the enamel being was thicker than that in the early bell stage. The length of ameloblasts increased from the presecretory to the secretory stage and decreased from the maturation to the protective stage. These results suggest that $T{\beta}4$ participates not only in the proliferation of oral epithelial cells during the early stage of tooth development but also regulates enamel protein secretion in ameloblasts and enamel mineralization.

• Journal of Electrical Engineering and Technology
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• 제8권5호
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• pp.1131-1137
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• 2013

This paper introduces novel a two-phase permanent magnet BLDC (PMBLDC) motor with both an asymmetric tooth and an auxiliary tooth in order to improve the dead point, efficiency and torque ripple. To calculate the merits of introducing each of the asymmetric tooth and the auxiliary tooth, characteristic analysis is performed respectively using finite element method (FEM). To maximize performance, we propose a novel model which combines the asymmetric tooth and the auxiliary tooth. To maximize the efficiency of the novel model, an optimal design is processed using the Kriging method and a genetic algorithm. Finally, an experiment is used to confirm the initial and optimal design results.

• 대한치과의사협회지
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• 제55권5호
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• pp.358-364
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• 2017

Nowadays, there has been an increasing interest in the preservation of natural dentition and the proper occlusion related to tooth wear for quality of life. Tooth wear means the loss of tooth enamel structure. This is happened by many causes which is the combined effects of many mechanisms. For keeping proper occlusion, dentists should check tooth wear status with acceptable methods and tools for the proper diagnosis. Until now, there have been many traditional qualitative ways to measure tooth wear which are intuitive, rapid, and simple. On the contrast, they are not objective nor reproducible. With the development of related technique, new quantitative methods using CAD and 3d scanners. This article aimed to introduce qualitative and quantitative methods for tooth wear measurements.