• Journal of Digital Convergence
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• v.11 no.10
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• pp.661-667
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• 2013

This paper aims to identify the relationship between the number of teeth of the elderly and their life happiness index. A face-to-face interview survey was conducted with elderly residents of Dong-gu, Daejeon from June 27 to July 25, 2012. A Tukey post hoc test and correlation analysis were implemented after a t-test and variance analysis. The results of analysis showed that satisfaction with life related to oral health was significant, but happiness in daily life had no significant difference. For the elderly, the quality of life related to oral health and happiness in daily life had no significant difference. Masticatory performance difference depending on usage of dentures also showed significant difference (p<0.001). The difference of masticatory performance depending on the number of teeth was analyzed by a correlation analysis. The present number of teeth, present anterior teeth and molars demonstrated a correlation. Quality in life related to oral health depending on the number of teeth correlated with the present number of teeth, present anterior teeth and present molars.

• The Journal of Korean Academy of Prosthodontics
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• v.31 no.4
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• pp.542-548
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• 1993

This study was designed to investigate the effect of missing teeth, prosthesis and malalignment on the smile. The full smile photographs of 145 Korean adults(male 114 : female 31) were taken and classified by the lip pattern, the relationship between the lip and the teeth, and the number of teeth displayed in a smile. Besides, the esthetic smile score were estimated by five dentists. Obtained data were compared and analyzed. The results obtained were as follows : 1. The esthetic level of missing teeth group and malaligned group was lower than that of the normal group. 2. The esthetic level of prosthesis group had no difference with that of the normal group. 3. The Number of teeth displayed in a smile had the most effect on the esthetic level in each experimental group.

• The Journal of the Korean dental association
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• v.58 no.1
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• pp.38-44
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• 2019

Although the Korea National Health and Nutrition Examination Survey (KNHANES) calculates oral health functional restriction rate and chewing discomfort rate every year, these two indicators are not all indicators of oral health. Therefore, indicators are needed to subdivide by age group and cover dental caries, periodontal disease, remaining teeth, and oral care use. The purpose of this study is to identify the key indicators of oral health in mature and middle age. The average number of existing natural teeth, the rates of 20 or more natural teeth, complaints of chewing discomfort, oral examination, periodontal disease and dental caries, were analyzed using KNHANES VI (2013-2015) as a complex sample. In the age group between 40 and 64, there were 25.2 natural teeth remaining, 91.4% natural teeth retention rate, 23% chewing discomfort rate, 34.7% oral examination rate, 38.7% periodontal disease prevalence, 6.46 the number of caries experience teeth, 21.4% interdental brush usage rate.

• 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.

• Restorative Dentistry and Endodontics
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• v.17 no.1
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• pp.214-221
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• 1992

The five different types of bacteria, Bacteroides, Actinomyces, Capnocytophaga, Streptococcus, Fusobacterium which had frequently been recovered in infected canals, were investigated. The purpose of this study was to investigate the bacteriologic status in the traumatized nonvital teeth, and to investigate the effects of bacteria on the size of the le8ion and on the discoloration of teeth. The canal contents of sxiteen traumatized nonvital teeth were sampled and cultured aerobically and anaerobically for growth in five selective agar plates for five bacterial species. The sizes of the radiolucent areas in periapical films were measured and according to the sizes, the samples were divided into two groups. The discoloration of the teeth was checked and according to the existence of the discoloration, the samples were divided into two groups, also. The difference of bacterial colonial numbers in each group was investigated and the following results were obtained. 1. In traumatized nonvital teeth, all of the samples gave bacterial growth except one case. 2. Streptococcus was isolated in four cases but Bacteroides, Actinomyces, Fusobacterium and Capnocytophaga were not isolated. 3. The number of bacterial colonies was not found to be related the size of the lesion periapical films. 4. The number of bacterial colonies was not found to be related the discoloration of teeth.

• The korean journal of orthodontics
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• v.53 no.3
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• pp.150-162
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• 2023

Objective: To investigate craniofacial differences in individuals with hypodontia and explore the relationship between craniofacial features and the number of congenitally missing teeth. Methods: A cross-sectional study was conducted among 261 Chinese patients (males, 124; females, 137; age, 7-24 years), divided into four groups (without hypodontia: no teeth missing, mild: one or two missing teeth, moderate: three to five missing teeth, severe: six or more missing teeth) according to the number of congenitally missing teeth. Differences in cephalometric measurements among the groups were analyzed. Further, multivariate linear regression and smooth curve fitting were performed to evaluate the relationship between the number of congenitally missing teeth and the cephalometric measurements. Results: In patients with hypodontia, SNA, NA-AP, FH-NA, ANB, Wits, ANS-Me/N-Me, GoGn-SN, UL-EP, and LL-EP significantly decreased, while Pog-NB, AB-NP, N-ANS, and S-Go/N-Me significantly increased. In multivariate linear regression analysis, SNB, Pog-NB, and S-Go/N-Me were positively related to the number of congenitally missing teeth. In contrast, NA-AP, FH-NA, ANB, Wits, N-Me, ANS-Me, ANS-Me/N-Me, GoGn-SN, SGn-FH (Y-axis), UL-EP, and LL-EP were negatively related, with absolute values of regression coefficients ranging from 0.147 to 0.357. Further, NA-AP, Pog-NB, S-Go/N-Me, and GoGn-SN showed the same tendency in both sexes, whereas UL-EP and LL-EP were different. Conclusions: Compared with controls, patients with hypodontia tend toward a Class III skeletal relationship, reduced lower anterior face height, flatter mandibular plane, and more retrusive lips. The number of congenitally missing teeth had a greater effect on certain characteristics of craniofacial morphology in males than in females.

• Journal of Korean society of Dental Hygiene
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• v.19 no.5
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• pp.731-742
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• 2019

Objectives: To analyze the association between sleep duration and the number of remaining teeth in people aged 65 years or older in order to provide basic data for improving sleep quality and developing oral health programs for teeth maintenance. Methods: The raw data for the analysis were obtained from the sixth Korean National Health and Nutrition Examination Survey (KNHANES) dataset, conducted between 2013 and 2015. The 4,340 subjects included in the study underwent oral examinations and then proceeded to answer related questions. The collected data were analyzed using SPSS (ver 23.0) program via composite samples, with the calculations for mean, standard deviation, chi-square test, and logistic return analysis being performed. Results: An analysis of the effect of sleep duration on the number of remaining teeth among people aged >65 years old showed that if the confounding variables were not corrected for, the risk of having less than 9 hours of sleep was 1.40 times higher (95% CI: 1.06-1.86). However, this was not statistically significant in models that corrected for gender, age, and other confounding variables (p>0.05). Conclusions: The association between sleep duration among the elderly with their number of remaining teeth was confirmed. Therefore, measures to improve sleep quality and oral care practices to maintain the remaining teeth in people over 65 years old should be developed.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.26 no.5
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• pp.507-513
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• 2000

Objective : The purpose of this study is to evaluate the vitality of the teeth in and adjacent to the mandibular fracture line according to variable conditions of fracture and to establish the protocol of treatment of fracture line teeth. Materials and Methods : The vitality of 97 teeth in fracture line and 104 teeth adjacent to fracture line of 52 patients were invested preoperatively. Of these, 66 teeth in fracture line and 72 teeth adjacent to fracture line were monitored at least 6 months after operation. An electric pulp tester was used to measure pulpal response. The relationships between the vitality of teeth in variable time(preoperation, immediate post-operation; within 1 week after operation, and 6 months after operation) and variable conditions of fracture(horizontal, vertical gap of fracture line, the number of fracture line)were evaluated statistically. Result : The vitality of fracture line teeth in the 6 months after operation statistically differed by the vertical gap of fracture line and the number of fracture line. The vitality of fracture line adjacent teeth in the immediate post-operation only statistically differed by the vertical gap of fracture line. There were statistically differences between preoperative EPT value and vitality of fracture line teeth on 6 months after operation. There were 5 cases of complications including periapical and periodontal abscess. Of these, only one tooth was extracted and the others were well treated with endodontic treatment and subgingival curettage. Conclusion : It is recommended to retain teeth and to monitor the vitality of teeth in and adjacent to fracture line, unless there is an absolute indication for extraction.

• Transactions of the Korean Society of Machine Tool Engineers
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• v.17 no.6
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• pp.124-131
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• 2008

There are many factors which affect the acoustical properties of a micro-speaker. Among the factors, the shape of the diaphragm is considered in this study. As an investigating method, the finite element methods and measurement techniques applied to study the acoustical properties according to diaphragm shape. In order to vary the stiffness of the diaphragm, the some patterns of comb teeth, such as the angle and the number of comb teeth, are applied to diaphragm. We can confirm that the change of the stiffness by the changing diaphragm shape affects the vibration and sound properties of the speaker. As a result, the reduction of the angle of the comb teeth increases the diaphragm stiffness and shifts the resonance frequency to a higher frequency range. The number of the comb teeth is related to the stiffness of the edge part.

• Journal of the korean academy of Pediatric Dentistry
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• v.7 no.1
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• pp.41-45
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• 1980

The term "Oligodontia" or "Hypodontia" have been used to describe variable degrees of reduction in number of teeth. Oligodontia may occur alone or as a result of some syndrome. Although the teeth are derived in part from ectoderm, the current opinion of reason of oligodontia should be reserved for those disorders in which there is abnormal development of one or more ectodermal tissues. 7 year 5 months old female was refered to the department of pedodontics, college of dentistry Yonsei university for evaluation and replacement of absent teeth. She had no special inf.ectious disease in her childhood, and her parents were healthy. She had no special syndrome of ectodermal disorders except the saddle nose, yellow and fine hair, and notched upper anterior central incisor. Panex radiogram was showing 6 anterior primary teeth, 2 permanent first molars and 2 unerupted first bicuspid in mandible. Another permanent teeth were absent. and normal number of primary and permanent teeth in maxilla. Lateral cephalogram showed no special abnormality in growth pattern. We had evaluated lower anterior decayed teeth with jacket resin and chrome steel crown and removable partial denture at missing area. We had got good results for rehabilitation of function and aesthetic.