• International Journal of Oral Biology
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• v.41 no.2
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• pp.63-68
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• 2016

The aim of this study was to investigate the effect of n-3 polyunsaturated fatty acids (PUFAs) on eruptive movement during tooth development. Sprague-Dawley (SD) rat pups were randomly divided into two groups; control group and experimental group. The experimental group was administered daily with n-3 PUFA by intraperitoneal (IP) injection. After 10 days postpartum, rat pups were sacrificed to evaluate the effect of n-3 PUFA on eruptive tooth movement. Histological analyses were by hematoxylin-eosin (H&E) staining. Tartrate-resistant acid phosphatase (TRAP) assay was performed to compare the osteoclast distribution in the bone matrix above the developing molar teeth. Incisor teeth eruptions were noticeably observed in IP group, as compared to control group. Rat pups in IP group showed faster tooth eruption on day 8 after birth. Through histological analyses, IP group showed thinner bone matrix and more osteoclasts above the $1^{st}$ molar teeth, as compared to control group. TRAP assay showed significantly stronger stained pattern that the osteoclast above the $1^{st}$ molar teeth in IP group, as compared to control group. The results suggested that n-3 PUFA could affect osteoclastic activity involved in bony remodeling during eruptive tooth movement.

• Restorative Dentistry and Endodontics
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• v.45 no.3
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• pp.29.1-29.9
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• 2020

This study describes the clinical steps taken in the treatment of a patient who had an avulsed right upper central incisor that presented with incomplete root development and chronic apical periodontitis. A 7-year-old boy was referred from a private dentist to a dental office specializing in endodontics. The tooth had remained in a dry environment for 20 minutes, and tooth replantation was performed at an emergency appointment. After clinical and radiographic examinations, root canal decontamination was performed, followed by several changes in intracanal calcium hydroxide medication. Blood clot formation was attempted, but bleeding within the root canal was insufficient; therefore, we opted for an intracanal medication change to stimulate mineralized tissue formation in the apical region. Root obturation was performed 45 days after the last change of intracanal medication, and clinical, radiographic, and tomographic follow-up examinations were performed at 3, 6, 18, and 40 months after the endodontic intervention. The increase in thickness and length of the root structure and the absence of root resorption were verified through follow-up examinations. Therefore, it was concluded that the procedures used were successful for tooth replantation.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.46 no.1
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• pp.78-83
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• 2020

Objectives: The discontinuation of bisphosphonate (BP) treatment before tooth extraction may induce medication-related osteonecrosis of the jaw (MRONJ). Whether the long-term discontinuation of BP treatment before tooth extraction affects the risk of developing MRONJ after tooth extraction or whether extended drug holidays induce systemic side effects remains unclear. The present study assessed the incidence of MRONJ among patients who underwent tooth extraction and did not discontinue BP therapy prior to the procedure. Materials and Methods: Patients were classified according to whether or not they discontinued BP therapy before tooth extraction. Differences in the incidence of MRONJ after tooth extraction were compared between the two groups using the chi-squared test. Results: The BP-continuation (BPC) and BP-discontinuation (BPDC) groups included 179 and 286 patients, respectively. One patient in the BPC group and no patients in the BPDC group developed MRONJ (P=0.385). The patients in the BPDC group stopped receiving BP therapy at a mean of 39.0±35.5 months prior to tooth extraction. Conclusion: The possibility of pre-existing MRONJ in the extraction area must be considered during the extraction procedure. Routine discontinuation of BP medications for several months before the extraction procedure should be carefully considered, as evidence of its efficacy in reducing the development of post-extraction MRONJ is limited.

• Imaging Science in Dentistry
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• v.53 no.4
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• pp.303-312
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• 2023

Purpose: This study investigated the prevalence of developmental and acquired pathologic conditions associated with impacted third molars (3Ms) in a Southern Brazilian population and evaluated whether demographic and tooth characteristics were correlated with the presence of bone or tooth lesions. Materials and Methods: Panoramic radiographs were assessed for developmental (bone-related) or acquired (tooth-related) pathoses associated with impacted upper or lower 3Ms. Data on tooth positioning, tooth development, and patient demographics were collected. A trained, calibrated postgraduate student evaluated all images. Binary and multivariate logistic regression models were used to assess associations between outcomes and the demographic and radiographic variables. The threshold for statistical significance was set at 5% (P<0.05). Results: The sample comprised panoramic radiographs from 2054 patients, predominantly female (59.2%), with a mean age of 27.2±11.5 years. Overall, 4066 impacted 3Ms were evaluated, revealing 471 (11.6%) developmental and 710 (17.5%) acquired pathoses. Among the developmental pathoses, 460 (95.2%) were indicative of dentigerous cysts. Male sex, lower 3M location, vertical or distoangular positioning, and incomplete root formation were associated with an elevated likelihood of developmental pathology. Lower tooth position, complete root formation, and partial eruption were linked to an increased probability of an acquired pathology in the third or second molar. Conclusion: The prevalence of pathologic conditions associated with impacted 3Ms was low. Male sex, lower 3M placement, horizontal or distoangular positioning, and incomplete root formation were associated with developmental pathoses, while lower tooth position, complete root formation, and partial eruption were related to acquired pathoses.

• Journal of Korean society of Dental Hygiene
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• v.9 no.4
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• pp.824-835
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• 2009

Objectives : The purpose of this study was identified about oral health status and oral health needs of elderly. Moreover this study would be based further research of development of oral health in elderly. Methods : This study was undertaken to determine the oral health status and the need of oral management of over 65years elderly who were with dental prosthesis in elderly welfare center and Kyung Ro Dong in Kyung Bok and Kyung Nam. The results were as follows. Results : The sample was 200 participants. The demographical characteristic were that 74.0% of participant was female, 29.0% of participant was 75~79 years old, 42.5% of participant was under elementary, and 45.5% of participant was living alone. 43.7% of participant was pain from muscle-skeletal disease, 37.1% of participant was cardiac-vascular disease, and 31.1% of participant was ophthalmic disease. In oral health status, 54.5% of participant was partly artificial tooth and 45% of participant was whole artificial tooth. 78.0% of participant used under 10 years with partly artificial tooth and only 27.4% were satisfaction with artificial tooth. 83.5% of participant used under 10 years with whole artificial tooth and only 26.4% were satisfaction with artificial tooth. In the oral health status of partly artificial tooth, the average of toothbrush was 2 times, 42.2%. The majority method of toothbrush was 'their own freely' 55.0%. The time of toothbrush was 'after meal' 81.8%. The study result showed that majority participant didn't experience of tongue brush, regular examination, scaling, and oral health education. In the need of oral management with the whole artificial tooth, the participant who used longer artificial tooth was significantly higher about artificial irrigation and the method of management(p<.05). The need of participant who answered 'don't gum massage', was higher of xerostomia treatment(p<.01) and halitosis treatment(p<.05). In the need of oral management with the partly artificial tooth, the participant who used longer artificial tooth was significantly higher about regular examination(p<.01), oral cavity massage(p<.05), scaling(p<.05), dental caries treatment(p<.01). The need of participant who answered 'don't satisfaction with artificial tooth' was higher of regular examination and scaling(p<.05). Conclusions : Oral management needs of elderly who kept artificial tooth or denture required were regular dental examination, xerostomia management, management of artificial tooth and irrigation, and management of bad breath. This results meaned the oral health intervention program for elderly was developed regularly.

• The Journal of the Korean dental association
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• v.42 no.2 s.417
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• pp.150-157
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• 2004

Inverted maxillary incisor is that maxillary incisor rotates counterclockwise direction. The cause of this 'Inverted incisor' is the injury of the deciduous predecessor transmitted to the developing permanent tooth germ or displacement of permanent tooth crown portion from unknown origin. Dilaceration, defined as a distorted root from, may result from mechanical injury during eruption period or ectopic development of tooth germ. This article presents a case of an inverted and dilacerated maxillary right central incisor. Through orthodontic traction, the dilacerated and inverted incisor was successfully moved into the proper position.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.13 no.1
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• pp.66-71
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• 2014

In this research, a material test machine is developed which uses a small electro-magnetic actuator and a leverage mechanism. The leverage mechanism amplifies the force from the electro-magnetic actuator. The electro-magnetic part operates more silently and cleanly than a hydraulic part. In a tooth material study, a test machine does not require a large force capacity because it handles only $4mm^2$-sectioned and short-span specimens. Conventional test machines such as those by Instron and the BOSE Enduratec ELF3200 have too high aforce capacity for a tooth material study. A test machine for a tooth material study requires an acting force only on the order of tens of Newtons (N) operating at several Hertz.

• The Journal of the Korean dental association
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• v.11 no.4
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• pp.287-291
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• 1973

A case report of replantation of extracted teeth. A 11-year-old female child patient whose right and left 1st premolars were dislocated by accident, which was treated by means of tooth replantation and obtained the following results. 1) In childhood whose development and growth were prominent prognosis were excellent. 2) The better results were drew by tooth fixation with acrylic resin after ligature the teeth with wire. 3) To treat the tooth replantation combination with canal treatment brings on the good results. 4) We can maintain the natural teeth, which could get the same function as before. According to previous results, the technique can be usd clinically.

• Proceedings of the Korean Powder Metallurgy Institute Conference
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• 2006.09b
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• pp.756-757
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• 2006

P/M enables the economical production of components for many kinds of gears. Functionally, the sub gear requires high tooth accuracy and bending fatigue strength. The whole tooth profile was sized after sintering to satisfy the gear tooth accuracy specification. The part was redesigned to reduce machining requirements. The required bending fatigue strength was achieved through appropriate material choice and induction of compressive residual stress by shotpeening after carburizing. The P/M sub gear replaced a forged steel gear, satisfied performance requirements, expanded the use of P/M applications and provided over 30% cost reduction.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2002.11a
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• pp.231-234
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• 2002

This paper considers a system related to biometrics which can control entrance and exit based on pattern and feature of a tooth. It is aimed at research and development of a controling entrance and exit system connected advanced image understanding technique using a tooth recognition that treats a tooth of simple and fixed structure. We think that the system is applied(or utilized) as pre-step or assistance means of face recognition and expect that the system achieves greatly effective results.