• Journal of dental hygiene science
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• v.23 no.3
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• pp.225-235
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• 2023

Background: This study aimed to analyze the effects of periodontal treatment and individual- and tooth-related factors on tooth extraction in people with disabilities. Methods: The Korea National Health Insurance claims data of individuals with disabilities aged 40~64 years with chronic periodontitis in 2008 were obtained. Of these, data on the disabled who underwent scaling/root plaining, subgingival curettage/periodontal surgery, or non-periodontal treatments, and data on their teeth were selected. The extraction of 716,688 teeth from 39,097 patients was tracked until 2018, and the patient- and tooth-level factors related to tooth loss were identified using a mixed-effect logistic regression analysis. Results: Data from approximately 17% of the teeth were extracted during a follow-up period of approximately 11 years. Among the tooth-level variables, scaling/root planing treatment at baseline and periodontal treatment during the follow-up period were associated with a lower risk of tooth loss (odds ratio=0.692 and 0.769, respectively, p<0.001). Non-vital teeth increased the risk of tooth loss by 3.159 times (p<0.001). Among the patient-level variables, females were less likely to have lost their teeth than males, and those with orthopedic impairment or brain lesions/mental disabilities, a higher age group, lower income level, or residents in medium/small cities or rural areas were more likely to have lost their teeth (p<0.001). Conclusion: Through approximately 11 years of follow-up, scaling or root planing, experience with periodontal treatment at least once, female sex, older age, lower income, smaller residential areas, type of disability, and pulp vitality were found to be associated with tooth loss in individuals with disabilities aged 40~64 years with chronic periodontitis. To prevent tooth loss in individuals with disabilities, it is necessary to establish a dental treatment plan that considers the timing of periodontal treatment and the characteristics of the patient and teeth.

• The Korean Journal of Zoology
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• v.6 no.1
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• pp.15-20
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• 1963

The characteristics of the pharyngeal bones and their teeth in Korean Cyprinids fishes, as a rule, are summarized as follow : 1. The materials 13 genera and 17 species from Nak Dong River. 2. Breadth of bone about 2.8(Cyprinus carpio) to 4.9(Culter brevicauda) in bone length. Length of bone about 8.5(Carassius carassius ) to 20.2 (Pseudogobio esocinus ) in body length. Breadth of pitted surface about 66%(Carassius carassius) to 85%(Acanthorhodeus asmussi ) of breadth of bone. 3. The position and distinct ratio of anterior angle correlated. 4. Posterior limb always longer than anteriro, but posterior edentulous process not shorter than anterior's or equal. 5. Zacco platypus with pitted surface on anterior limb , but Z.temmincki without it. 6. Teeth one to three rowed in accordance with the differences of each genus : a. one rowed genera ..... Carassius , Pseudorasbora, Sarcocheilichthys (Sakiyae), Pungtungia, Acheilognathus, Acanthorhodeus. b. two rowed genera ........ Pseudogobio, Gnathopogon, Tribolodon. c. Three rowed genera .... Cyprinus, Hemibarbus, Zacco , Culter 7. Teeth of main (primary ) row with four or five teeth is symmetrized exceptive three genera (Tribolodon, Zacco, Culter). 8. Grinding surface and bill type correlated. 9. In Acheilognathus, A.Yamatsutae have one or two indistinct serration but each individual is unlike.

• The korean journal of orthodontics
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• v.33 no.5 s.100
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• pp.339-350
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• 2003

The purpose of this study was to investigate the micro-implant height and anterior hook height to prevent maxillary six anterior teeth from lingual tipping and extruding during space closure. We manufactured maxillary dental arch form, bracket and wire, using the computer aided three-dimensional finite element method. Bracket was $.022'{\times}.028'$ slot size and attached to tooth surface. Wire was $.019'{\times}.025'$ stainless steel and $.032'{\times}.032'$ stainless steel hook was attached to wire between lateral incisor and canine. Length of hook was 8mm and force application points were marked at intervals of In. Four micro-implants were implanted on alveolar bone between second premolar and first molar. The heights of them were 4, 6, 8, 10mm starting from wire. We analyzed initial displacement of teeth by various force application point applying force of 150gm to each micro-implant and anterior hook. The conclusions of 4his study are as the following : 1. When the micro-implant height was 4m and the anterior hook height was 5mm and below, anterior teeth were tipped lingually. When the anterior hook height was 6mm and above, anterior teeth were tipped labially. 2. When the micro-implant height was 6mm and the anterior hook height was 6mm and below, the anterior teeth were tipped lingually. When the anterior hook height was 6m and above, the anterior teeth were tipped labially. But lingual tipping of anterior teeth decreased and labial tipping Increased when the micro-implant height was 6mm, compared with 4mm micro-implant height. 3. When the micro-implant height was 8mm and the anterior hook height was 2mm, the anterior teeth were tipped lingually. When the anterior hook height was 3mm and above, labial tipping movement of the anterior teeth increased proportionally. 4. When the micro-implant height was 10mm and the anterior hook height was 2mm and above, labial tipping of the anterior teeth increased proportionally. 5. As the anterior hook height increased, aterior teeth were tipped more labially. But extrusion occurred on canine and premolar area because of the increase of wire distortion. 6. Movement of the posterior teeth was tipped distally during maxillary six anterior teeth retraction using micro-im plant because of the friction between bracket and were Based on the results of this study, we could predict the pattern of the tooth movement according to position of micro-implant and height of anterior hook. It seems that we can find the force application point for proper tooth movement in consideration of inclination of anterior anterior teeth, periodontal condition, overjet and overbite

• Transactions of the Korean Society of Mechanical Engineers A
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• v.27 no.5
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• pp.758-763
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• 2003

A profile shifted gear system was analyzed to select the optimum profile shift coefficient, which minimizes gear teeth deflection. Contact force and deformation overlap were calculated by means of FEM and contact theory. The deformation overlap is suggested for an effective indicator to represent the whole deformation of gear system. The optimum value of profile shift coefficients was presented with respect to the deformation of gear system.

• The Journal of the Korean dental association
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• v.19 no.2 s.141
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• pp.159-162
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• 1981

The author devised a simple technique for duplicating occlusal contour of natural teeth on the prepared abutments using hard stone index obtained from the study cast of natural teeth. Throughout this author devised method, the following advantages are studied. Firstly the dentist can obtain an ideal occlusal wax patterns which have arrived at the physiologic state through a long period of adjustment to various habits and functional movements. Secondly the construction procedure is simple, and thirdly it is easy to adjust wax pattern of nomal natural teeth which duplication is required.

• Journal of Korean Academy of Oral and Maxillofacial Radiology
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• v.2 no.1
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• pp.37-39
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• 1972

The author has observed on the impacted teeth of 11 cases from 484 full-mouth roentgenograms of dental students S. N. U. (except 3rd molar) These studies are very significant in oral surgery and orthodontic problems. Most of the impacted teeth are located in maxilla and among them 7 cases are impacted central incisors the others are lateral incisors, and cuspids. The form of impactions are vertical, horizontal and inverted positions.

• The Journal of the Korean dental association
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• v.52 no.2
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• pp.69-74
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• 2014

Many patients have been suffering the continued hypersensitivity and pain of teeth after operative or endodontic treatment. The primary purpose of this paper is to examine the causes of the pain and the hypersensitivity of teeth, and to resolve conflicts between dentists and patients. The secondary aim of this paper is to prevent medical disputes. Evidence-based dentistry and making a good relationship with patients will reduce disputes on dental treatment.

• Journal of Korean society of Dental Hygiene
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• v.14 no.3
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• pp.399-406
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• 2014

Objectives : The purpose of the study is to investigate the oral health behaviors between students studying in Vancouver, Canada and college students in Daejeon, Korea. Methods : A self-reported questionnaire was filled out by 239 students in November, 2013. The questionnaire consisted of oral health behavior including tooth brushing methods between two countries. Chi-square test and t-test were analyzed. The analyses were conducted using R version 2.14.2(R Foundation for statistical Computing, Vienna, Austria). Results : The number of tooth brushing in Korean students was higher than those in Canada. Fifty nine percent of the Koreans brushed their teeth 3 times a day while 62.3% of students in Canada brushed their teeth 2 times a day(p<0.0001). Those who were taught on oral health education tended to brush the teeth more frequently that those who had not. Koreans and Japanese tended to brush teeth more frequently after breakfast than the Taiwanese(p=0.005). Koreans also brushed teeth after dinner more frequently than Japanese, Taiwanese, and other foreigners(p=0.012). Conclusions : This study indicated that Koreans have better oral health behaviors in comparison to students studying abroad.

• Journal of Korean society of Dental Hygiene
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• v.20 no.5
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• pp.545-559
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• 2020

Objectives: The purpose of this study was to systematically analyze and examine the relationship between the number of lost teeth and quality of life (QoL) among elderly. Methods: Papers published in Korean and English between 2000 and 2020 were searched. Relevant papers were selected by two independent readers according to predefined exclusion criteria. Quality assessment and consistency tests were conducted using ROBIS. Results: Twelve of the 854 studies were targeted, and the analysis confirmed that tooth loss was related to a decrease in the QoL in 11 studies. Tooth loss negatively affected the QoL among the elderly. However, one study indicated that the QoL and number of teeth were not related. Rather, dry mouth affected the QoL, and cavities caused by oral dryness led to tooth loss. Most of the selected studies indicated that the QoL of elderly individuals with a single tooth was higher than that of those with no teeth. Conclusions: This study provides strong evidence that tooth loss in the elderly is associated with impairment of QoL.

• Journal of the korean academy of Pediatric Dentistry
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• v.10 no.1
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• pp.131-138
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• 1983

381 students including elementary school boys 75, girls 76 & middle school boys 115, girls 115 were examined to study the factors of dental esthetic self-evaluation: as measured by questionnaire & dental examination. The following results were obtained: 1. In the case of the girls, the more severely rotated or displaced the upper anterior teeth were, the uglier they felt themselves. 2. The students showed the tendency to answer that they were satisfied or had no feeling one way or the other even though their teeth were less straight than others. 3. Most of the students could not relate their teeth to the over-all facial appearance. 4. In the case of the elementary-school-boys, they felt themselves ugly when the overjet & overbite were excessive: in the case of the middle-school-girls, they felt themselves ugly when the rotation & displacement of the upper & lower anterior teeth were severe. 5. Angle's classification showed no statistical significancy.