• Journal of dental hygiene science
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• v.16 no.3
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• pp.217-224
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• 2016

The aim of this study was to evaluate whether the number of existing permanent teeth is associated with chronic obstructive pulmonary disease (COPD) in a representative sample of Korean adults. Data from 3,107 subjects who participated in the 2009 Korea National Health and Nutrition Examination Survey were examined. The dependent variable was COPD and the independent variable was the number of existing permanent teeth. Spirometry results were classified into three groups (normal pattern, restrictive pattern, and obstructive pattern) by trained technicians. We used dichotomized COPD variables (no vs. yes). The number of existing permanent teeth was evaluated by oral examination and divided into 3 groups (0~19, 20~27, and 28). Demographic factors (age group and sex group), socioeconomic status (education and income), health behaviors (smoking and drinking), oral health and behavior (frequency of toothbrushing; periodontitis; decayed, missing, filled, permanent teeth index; and denture status), and general health status (body mass index, diabetes mellitus, and hypertension) were included as confounders in the analysis. Bivariate analysis and multivariate logistic regression analyses including confounders were applied, and all analyses considered a complex sampling design. Stratified analysis was performed by smoking status. After controlling for various confounders, there was a significant association between the number of existing permanent teeth and COPD (odds ratio [OR], 1.90; 95% confidence interval [CI], 1.20~3.00 for the 20~27 group; OR, 3.93; 95% CI, 1.75~8.84 for the 0~19 group). The association was more significant in current smokers (OR, 8.90; 95% CI, 2.53~31.33). Our data indicate that the number of existing permanent teeth was independently associated with COPD, especially in current smokers. Further longitudinal research is needed to determine whether oral health promotion plays a role in the improvement of lung function and prevention of COPD.

• The Journal of Korean Academy of Prosthodontics
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• v.11 no.1
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• pp.15-21
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• 1971

The prime objective of this study was to analyze the positional relationship of the lips to the anterior teeth according to age, sex, and both sides of the dental arch in 381 healthy Korean adults with normal occlusion ranging from 17 to 70 years over old. The results were as follows; 1. In the position of the corner of the mouth to the teeth, the range from center of canine to mesial side of first premolar was revealed the incidence of 81~87%, the distal side of canine was the hiqhest frequency of 39~43%. 2. A straight type (76~79%) of lip line was prevailed against the curved type in rest position. 3. In the exposed type of anterior teeth to upper lip in rest position, type III(50~52%) Grade 2 (26~29%) was revealed the highest frequency of occurences. 4. No significant difference in both sexes and sides of the dental arch was observed. 5. Lip position to the teeth with aging was showed the tendency toward straight type in lip line and toward reduction of the number of exposed type of upper anterior teeth to upper lip, and the corner of the mouth was placed posteriorly.

• Journal of Korean society of Dental Hygiene
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• v.11 no.1
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• pp.127-136
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• 2011

Objectives : The writer aimed to examine the dynamic aspect on damage and to be conducive to the swift cure according to right treatment to educate prevention of injury through surveying on the number of the damaged teeth given injury, tooth kind, type in damage, place and cause for being damaged, frequency by month and by time level, and location of the damaged tooth. Methods : Targeting 343 teeth of receiving injury in 201 patients who visited the department of pediatric dentistry, the department of preservation, and the oral and maxillofacial surgery in a dental hospital in Cheonan city from April 2007 to April 2009, by having the dental injury as the main reason, the following conclusions were obtained. Results : 1. Deciduous teeth were indicated to be the highest in imperfect luxation with 60.7%, and were indicated to be in order of crown fracture with 25.5%, root fracture with 12.4%, and perfect luxation with 1.4%. The permanent teeth were indicated to be the highest in crown with 58.1%, and were indicated to be in order of imperfect luxation with 27.3%, root fracture with 13.1%, and perfect luxation with 1.5%(p<0.001). 2. In case of deciduous teeth for a place with damage, the home was indicated to be the highest with 31.7%. The permanent teeth were indicated to be the highest(p<0.001) in the road and stairs with 40.4%. As to a cause for damage, both deciduous and permanent teeth were indicated to be the highest(p<0.001) in a cause for falling with 53.1% and 30.8%, respectively. 3. As for a treatment method, in case of deciduous teeth, the close observation was indicated to be the highest with 46.9%. In permanent teeth, the resin restoration was indicated to be the highest(p<0.001) with 22.2%. Dental injuries in deciduous teeth and permanent teeth are showing diverse aspects. Conclusions : It is important to arrange guidelines on cure of the damaged teeth by injury through continuing a dynamic research on these aspects. Also, the damage in deciduous teeth may have direct and indirect influence upon growth in successional permanent teeth. Thus, through careful treatment, the injury needs to be minimized. It is considered to be likely necessary for a right coping method when injury occurs, and above all, for enough prior education so that injury cannot occur.

• Journal of Korean Academy of Oral and Maxillofacial Radiology
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• v.20 no.1
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• pp.79-89
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• 1990

The incidence and several characteristic features of fused and geminated teeth were studied radiographically, with full mouth periapical radiogram and pantomogram, in 4201 patients of mixed dentition and 5358 patients of permanent dentition. The obtained results were as follows: 1. The prevalence was revealed to 2.86%, 0.32%, 0.33%, and 0.06% in deciduous fused tooth, permanent fused tooth, deciduous geminated tooth and permanent geminated tooth respectively, and these anomalies were occured in female more than male. 2. Fused teeth were observed predominantly in lower anterior teeth area, especially in lateral incisor and canine region, and many cases of deciduous geminated tooth were observed in upper central incisor region. 3. Congenital missing rates of succedaneous tooth in deciduous fused teeth were 57.1 %, 85.7%, 71.0%, 69.0% in upper right and left central-lateral incisor regions, lower right and left lateral incisor-canine regions, respectively. 4. Prevalence of dental caries was 42.3%, 18.8% and 5.6% in deciduous fused, deciduous geminated and permanent fused tooth, respectively. 5. In classifying of fused and geminated teeth into 9 types, by following appearance such as number of crown, root, pulp chamber and pulp canal of those teeth, it was more favorable that Type Ⅰ(2 crown, 2 root, 2 pulp chamber, 2 pulp canal) in deciduous fused tooth and Type Ⅸ (I crown, 1 root, 1 pulp chamber, 1 pulp canal) in permanent fused tooth, deciduous and permanent geminated tooth.

• Journal of dental hygiene science
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• v.15 no.3
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• pp.340-347
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• 2015

The purpose of this study is to analyze the factors of oral function associated with number of present teeth (NT) in Korean elderly adults. The research was designed as cross-sectional study using the data of the 4th Korea National Health and Nutritional Examination Survey, and the samples were selected by stratified clusters sampling. The subjects aged 55 to 84 years were 4,780 that joined the oral examination survey and questionnaires. The respective variables reflecting socioeconomic status, subjective health status and oral function factor were analyzed and their distributional differences were confirmed by complex sampling logistic regression analysis. Multivariable liner regression models considering covariates were applied to explain the associations between the number of present teeth and other variables. Gender, educated level, illegal dental treatment, self-rated oral health and oral functional factors, including chewing behavior and speaking behavior, were associated with the number of present teeth (p<0.05). Subjects with better self-rated oral health had more NT than those with worse. Subjects with worse speaking behaviors had less NT than those with better. Interventions aiming to enhance oral health in elderly adults should consider socioeconomic, demographic, and oral functional factors.

• Journal of the korean academy of Pediatric Dentistry
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• v.23 no.2
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• pp.291-305
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• 1996

The purpose of this study was to investigate the distribution of nerves in the dental pulp of early extracted primary teeth, normal exfoliated primary teeth, partially-erupted, nonfunctional, premolars, and erupted, functional, premolars. Numbers of sample were 10 teeth in each group. The distribution of nerves in the dental pulp were investigated by means of immunohisto chemistry for detection of neurofilament protein(NFP). The results were as follows: The early extracted primary teeth exhibited patterns of innervation similar to those observed for young permanent teeth. The plexiform arrangement of fibers was not evident in the primary teeth. Most nerves appear to terminate about the odontoblasts. As primary teeth began to undergo root resorption, degenerative changes such as vesicles and fragmentation appear in the nerves. The quantity of neural tissue also decreased. In teeth in which the roots were almost completely resorbed only a small number of nerves remain. There was a decrease in the number of terminal branches in the pulp of the partially erupted, nonfunctional, premolars and those present reached the pulpo-odontoblastic border. The nerve terminals in the pulp of the erupted, functional, premolars were traced to the dentinal tubule and a few nerve fibers formed loops in the predentin.

• Proceedings of the KSME Conference
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• 2004.11a
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• pp.226-231
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• 2004

Press fitting method for joining of a hybrid tube and steel ring with small teeth for automotive aluminum/composite hybrid propeller shaft was devised to improve reliability and to reduce manufacturing cost, compared to other joining methods such as an adhesively bonded joint, bolted joint or welded joint. To obtain high strength of the press fit joint, an optimal design method for the teeth was devised with respect to number and shape of the steel teeth. Torsional static, fatigue tests and finite element analysis of the press fit joint were performed with respect to experimental variables. The developed optimal design method predicted well the static torque capability and failure mode of the press fit joint. Also, it provided design guide line of press fit joint for improving torsional static and fatigue characteristics.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2006.05a
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• pp.171-172
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• 2006

Most existing studies for stress analysis of teeth have employed small number of teeth, and used big element size using F-E models. Therefore, the results are not accuracy enough for showing the internal stress variation. 15 males' and 13 females' mandibular first premolar are employed for internal structure's study of teeth and small element size for a FE model are used. According to these processes, stress distribution of internal parts of teeth are well shown, and the stresses are varied a lot between enamel layer and dentine layer, but there is little variation on pulp chamber.

• The Journal of Advanced Prosthodontics
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• v.8 no.4
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• pp.321-328
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• 2016

PURPOSE. This study was designed to investigate the maintenance of teeth and implants in patients with viral liver disease. MATERIALS AND METHODS. 316 patients without any significant systemic disease were selected as a control group. Liver disease group was consisted of 230 patients. Necessary data were collected using clinical records and panoramic radiographs. Then, the patients were subdivided into 2 groups based on the type of active dental therapy received before maintenance period (Pre-Tx). Analysis for finding statistically significant difference was performed based on the need for re-treatment of active dental therapy (Re-Tx) and change in the number of teeth (N-teeth) and implants (N-implants). RESULTS. Comparing to control group, the patients with liver disease showed higher value on N-teeth, N-implants, and Re-Tx. Statistically significant differences were found on N-teeth (P=.000) and Re-Tx (P=.000) in patients with non-surgical Pre-Tx. Analysis based on severity of liver disease showed that N-teeth and Re-Tx were directly related to severity of liver disease regardless of received type of Pre-Tx. Significant differences were found on N-teeth (P=.003) and Re-Tx (P=.044) in patients with non-surgical Pre-Tx. CONCLUSION. In this study, it was concluded that liver disease might influence the loss of teeth and cause the relapse of dental disease during maintenance period in patients. A significant positive relationship between tooth and implant loss and severity of liver disease seems to exist.

• Imaging Science in Dentistry
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• v.46 no.4
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• pp.251-258
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• 2016

Purpose: The aim of this study was to examine the radiographic features associated with impacted premaxillary supernumerary teeth, to determine the relationship between their characteristics and their effects on permanent incisors, and to investigate the types of orthodontic treatment that patients received after the extraction of impacted supernumerary teeth. Materials and Methods: The clinical records and radiographs of 193 patients whose impacted premaxillary supernumerary teeth were removed were retrospectively reviewed, and 241 impacted supernumerary teeth were examined. Cone-beam computed tomographic images and panoramic radiographs were examined to determine the number, location, sagittal position, orientation, and morphology of the supernumerary teeth. Their effects on permanent incisors and the orthodontic treatment received by patients after the extraction of the supernumeraries were also investigated. Results: Supernumerary teeth were most frequently observed in the central incisor region, in the palatal position, in the inverted orientation, and were most commonly conical in shape. The most common complication was median diastema, followed by displacement and delayed eruption of the adjacent incisors. Ten (71.4%) of the 14 odontomas showed delayed eruption of the adjacent incisors. Displacement of the incisors was more frequently observed in association with supernumerary teeth with tuberculate or supplemental shapes. Orthodontic traction was most frequently performed after the removal of odontomas. In 32 cases (13.3%), permanent incisors erupted after the orthodontic creation of sufficient space. Conclusion: Median diastema was most common complication. The delayed eruption of incisors was common in supernumerary teeth with a vertical orientation and an odontoma shape.