• Journal of the korean academy of Pediatric Dentistry
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• v.36 no.4
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• pp.625-630
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• 2009

Root resorption of primary teeth usually occurs as the succeeding permanent teeth erupt, which induces differentiation of the hemopoietic cells into osteoclasts. Their root resorption pattern reflects the eruption path of the succeeding permanent teeth, and eventually the primary teeth shed as their succeeding permanent teeth erupt. Even when a permanent tooth germ is congenitally missing, root resorption of the corresponding primary tooth may still occur due to various factors, such as inflammation, traumatic occlusal force, and weakness of periodontium etc. Such congenital missing of permanent teeth is a commonly observed phenomenon in human be ing, and it often accompanies delayed retention of primary teeth. The etiologic factors for congenital missing in elude not only systemic diseases, but also local factors and human evolution process. In the radiographs of the cases in this report, the primary teeth without succeeding permanent teeth show pathologic root resorption. Root resorption progressed about 1/2~3/4 of the roots, and the surfaces of the resorption area were irregular. Considering high susceptibility of the periodontal ligament of primary teeth to root resorption, pathologic root resorption of primary teeth with delayed retention can be explained by the increased masticatory muscle force and abnormal occlusion developed during the mixed dentition. When the primary teeth without succeeding permanent teeth are lost, decision for space maintenance is required and long-term treatment plan for further prosthetic or orthodontic treatment should be establsihed.

• Journal of the korean academy of Pediatric Dentistry
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• v.32 no.4
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• pp.717-725
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• 2005

It is widely known that individuals with Down's syndrome(DS) often develop early onset severe periodontal diseases. In this study, We examined the prevalence of periodontopathic bacteria in DS patients to compare controls with mental disabilities(MD) The subjects were 27 DS patients (7 to 19 years old) and 27 age-matched controls with MD. Plaque index and gingival index were measured. And 5 pathogens, Actinobacillus actinomycetemcomitans, Porphyromonas gingivalis, Tannerella forsythia, Treponema denticola, Fusobacterium nucleatum, were surveyed in subgingival plaque samples using a polymerase chain reaction. No significant difference in plaque index and gingival index were observed between the DS and control group. The prevalence in DS was 96.3% for F. nucleatum, 74.1% for T. forsythia, 63.0% for P. gingivalis, 55.6% for A. actinomycetemcomitans. 40.7% for T. denticola. No significant differences were observed in the prevalence of periodontopathic bacterias between the DS and control. Prevalence of P.g(16.7%) at age $7{\sim}10$ is lower than other age group in DS, but its prevalence increased with age. Prevalence of A.a(83.3%) is peak at age $7{\sim}10$ in DS. These results suggest that various periodontopathic pathogens can colo nize in the very early childhood of DS and MD patients. But no significant difference was observed in the prevalence of periodontopathic bacterias between the DS and control.

• Journal of Oral Medicine and Pain
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• v.30 no.2
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• pp.201-214
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• 2005

Age estimation is fundamental and important in personal identification with forensic medicine and dentistry. Recently, a lot of studies using various part of the body have been done for age estimation. Age estimation with teeth is the most significant method comparing ones with other part of the body. Gustafson method and Johanson method using postmortem teeth have been authorized in accuracy and systemization and used domestically and internationally. The verification of the accuracy in above methods had been tried many times but it is still rare in Korea. Fifty-nine teeth(incisors, canine, premolars and molars) which were extracted due to periodontal diseases or orthodontic problem were collected. Present study is to 1) compare the accuracy of estimated age in applying Gustafson method and Johanson method to the teeth in Korea, 2) compare and analyze the correlation with results using Gustafson method and Johanson method by age, gender, maxilla - mandible and anterior - premolar - molar. Teeth were embedded in resin and sliced and then examined each one using Gustafson method and Johanson method. The results are as follows: 1. Actual age was a significant difference in estimated age by Johanson method. Actual age was a significant correlation in estimated age by Gustafson method and modified Johanson method. Modified Johanson method was more significant than Gustafson method. 2. In estimated age by Gustafson method, Johanson method and modified Johanson method, there was no significance with actual age by location and gender. 3. In estimated age by Gustafson method, Johanson method and modified Johanson method, there was significance with actual age by age group. Finally, Gustafson method and Johanson method can be used in Korea. To make more accurate verification, however, it needs more specimen and postmortem teeth. Johanson equation proposed by himself has to be developed by further studies.

• Journal of dental hygiene science
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• v.11 no.6
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• pp.535-542
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• 2011

The purpose of this study was to examine the state of smoking among adolescents and their smoking-related oral health knowledge. The subjects in this study were the teens who were selected by convenience sampling from among the students who were in their first, second and third years in four different middle schools in the city of Iksan, North Jeolla Province. A self-administered survey was conducted from June 14 to July 12, 2011, and the answer sheets from 1,219 respondents were selected for analysis. The collected data were analyzed by the statistical package 12.0, and the findings of the study were as follows: 1. The smoker students accounted for 10.6 percent. The boys and girls who smoked respectively represented 16.0 and 5.4 percent. 2. As for the period of smoking, the largest group that accounted for 51.6 percent smoked for less than a year. Concerning the amount of daily smoking, the greatest group that accounted for 91.9 percent smoked less than 10 cigarettes. As to the motivation of smoking, the biggest group that represented 52.8 percent started to smoke out of curiosity. 3. Regarding smoking-related oral health knowledge, they got a mean of 0.85. Their scores in knowledge of oral malodor(0.95), oral cavity cancer(0.94) and periodontal diseases(0.93) were above the average, and their scores in knowledge of dental caries(0.70) and blunting of taste(0.77) were below the average. 4. The seventh graders got the best score of 5.28 in smoking-related oral health knowledge(p<0.01), and the students who were more satisfied with their life had a better oral health knowledge(p<0.05). 5. The senior students were more dependent on nicotine(p<0.01), and the number of smoking days(${\beta}=0.407$, p<0.001) and the period of smoking(${\beta}=0.235$, p<0.01) affected their nicotine dependence.

• Journal of the korean academy of Pediatric Dentistry
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• v.49 no.2
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• pp.206-216
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• 2022

This study aimed to investigate the frequency of dental visits after coronavirus disease 2019 (COVID-19) in children and adolescents in comparison to that of adults. The data on the number of dental visits on the basis of different classification and treatment codes for all the age groups were provided by the Health Insurance Review and Assessment Service from January 2017 to December 2020. To reduce the impact of the population change, dental visits per 1000 people was used. After the start of the pandemic, dental visits per 1000 people decreased in all age groups when analyzed for the diseases of pulp and periapical tissues classification code and dental visits per 1000 people decreased over 5 years age groups when analyzed for the pulp treatment code. Regarding the restorative treatment code, visits in the 0 - 19 years age group decreased after the pandemic. Based on the comparison of the number of confirmed COVID-19 cases to that of monthly dental visits by treatment codes, the change rate of pulp and restorative treatments gradually decreased after the waves of the pandemic in February and August 2020 in Korea. Furthermore, dental visits per 1000 people for gingivitis and periodontal disease classification code increased after the pandemic in all age groups. The rate of decrease in dental visits per 1000 people for restorative treatments in children and adolescents was higher than that in adults. The rate of decrease in the number of dental visits for multi-visit pulp treatments showed a rapid decrease as compared to that of 1-visit pulp treatments after the pandemic. This study identified changes in the number of dental visits of children and adolescents after COVID-19 transmission in comparison to that observed in adults.