• Journal of Korean society of Dental Hygiene
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• v.17 no.1
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• pp.13-25
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• 2017

Objectives: The purpose of this study was to compare colony forming unit (CFU) method and multiplex real-time polymerase chain reaction (MRT-PCR) method for accurate quantitative analysis of bacteria. Methods: We compared the CFU method and the MRT-PCR method, which are still used in Korea, for Prevotella intermedius (P. intermedius), a periodontal disease pathogen selected by MRT-PCR, and Streptococcus mutans (S. mutans), a dental caries causative organism. The subjects of this study were 30 patients who visited the C dental hospital. Results: Total microorganisms in MRT-PCR method were significantly higher in both types of bacteria (p<0.05), since DNA of dead bacteria was also analyzed. This was because the periodontal dise(-) anaerobes, and even dead bacteria contain large amounts of toxic substances called LPS in the extracellular membrane, and fimbriae and pili, which are motility structures, still remain as a strong toxic substance in periodontal tissue. Conclusions: Therefore, in terms of the total amount of bacteria found, the MRT-PCR method will be a useful technique for searching all the bacteria in the oral cavity including live bacteria, as well as sterilization.

• Journal of Korean society of Dental Hygiene
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• v.11 no.5
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• pp.707-715
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• 2011

Objectives : The objective of this study was to assess a level of oral health related quality of life(OHRQoL) for rural communities elderly and to determine the association between OHRQoL and socio-economic position. Methods : The study population was elderly(60+year-old) residents of PyeongChang county, Jeongseon county, Yeongwol county, Gangwon province. A total of 171 people were invited to participate. Oral health related quality of life was measured using the GOHAI. The data were analyzed with Mann-Whitney U test or Kruskal-Wallis test and to assess socio-economic inequalities in OHRQoL(GOHAI), we used multi-variable logistic regression models. We used models adjusting for age, sex, family status factors(Model I) and compared them to models additionally adjusting for stress level(Model II). Results : There were significant differences in lower score of GOHAI at lower age group and live alone group. And we found that lower SES was significantly associated with lower score of OHRQoL. Social gradient in the score of OHRQoL persisted when adjusted for age, sex, family status, stress level. Conclusions : We recommend that oral health promotion program should be developed after due consideration SES for rural communities elderly because OHRQoL of rural communities elderly was low and association between SES and OHRQoL for rural communities elderly.

• Journal of Korean society of Dental Hygiene
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• v.17 no.4
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• pp.657-667
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• 2017

Objectives: The aim of this study was to evaluate the potential of dental erosion by three different types of commercial fermented milk on the enamel surface of bovine teeth. Methods: Forty bovine teeth (four groups of 10) were immersed in fermented milk (experimental groups: liquid type, condense-stirred type and condense-drink type) or mineral water (control group) for 1, 3, 5, 10, 15, 30, 60, 90 and 120 minutes. Enamel surface microhardness was measured before and after treatment with a microhardness tester, and Scanning Electron Microscope (SEM) was used to assess the enamel surface morphology. Results:Changes in enamel surface microhardness (before-after treatment; ${\Delta}VHN$) were significantly different among the four groups (p<0.05). ${\Delta}VHN$ was highest in the liquid type group, followed by the condense-stirred type, condense-drink type, and control groups. The ${\Delta}VHNs$ of three types of fermented milk groups were higher than that of the control group (p<0.05). The liquid type group showed higher ${\Delta}VHN$ than the other two types of condense fermented milk groups (p<0.05). However, there was no significant difference in ${\Delta}VHN$ between the two types of condense fermented milk (p>0.05). The results of SEM observation have shown the most severe surface damage in bovine teeth immersed in the liquid type of fermented milk. Conclusions: In this study, it appears that liquid type fermented milk causes greater development of dental erosion. The physical properties and pH of fermented milk types must be considered for prevention of dental erosion associated with ingestion of fermented milk.

• The Journal of Korean Society for School & Community Health Education
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• v.11 no.2
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• pp.57-69
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• 2010

Objectives: The purpose of this study was to evaluate the effect of nutrition and health-related behavior on quality of life in some adolescents. Methods: The subjects of this study were total 243 middle school students in Deagu, Korea. A self-administrated questionnaires were used to obtain general characteristic, health-related behaviors, nutrition status, and quality of life. The height and weight of participants were measured, then calculated body mass index(BMI). To assess an association between nutrition and health-related behavior and quality of life, an univariate and multivariate analysis were applied using PASW Statistics 18(SPSS Inc, Chicago, USA). Results: As the perceived general health and subjective happiness were better, there were a higher score for all subscales of quality of life. The adolescents, the highest of total intake of energy and overweight, were more likely to have lower quality of life score but there were no statistically significant. Factors related to the adolescents's quality of life were found to be gender, perceived general health, subjective happiness and physical activity. Conclusions: Various factors were related to quality of life in adolescents. To improved the quality of life in adolescent, it is need to develope a physical activity program and counseling of mental condition as well as adequate diet programs.

• The Journal of the Korean Society for Microbiology
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• v.18 no.1
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• pp.23-29
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• 1983

An epidemiological survey was carried out to identify the serotypes of Streplococcus mutans isolated from carious lesions of 65 caries-active subjects(CAS) and sound tooth surfaces of 40 caries-free subjects(CFS). The autoclaved antigen extract was performed on each isolate, and then, serotypes of the isolates were determined in agar-gel immunodiffusion test. The results were as follows: 1. S. mutans was found in 78% of the samples of CAS, and of CFS. The difference of isolation frequency between CAS and CFS was not observed. 2. Only one serotype per single subject was detected in 61% of total samples, in remaining 39% of samples two or more serotypes were detected. 3. In 41.2% of CAS samples plural serotypes of S. mutans were found, whereas 35.5% of CFS samples showed plural serotypes distribution. 4. The most frequently identified serotype in each subject was serotype c; 69.5% of subjects harbored serotype c S. mutans. Serotype d was next most frequently isolated from subjects, comprising 23.2%. 5. Serotype c strain was found in 64.7% of CAS, 77.4% of CFS. 6. Of the isolates from CAS and CFS, serotype c was most commonly found, comprising 48.8%, serotype d was found in 16.3%, serotypes f. e, and g comprising 13.2%, 9.3%, and 7.8% respectively. Serotypes a and b were also found but in far lower frequencies(2.3%, 0.8%). 7. Serotype c strains were more found in CFS than in CAS, but serotypes d and e were more found in CAS.

• Journal of Korean society of Dental Hygiene
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• v.16 no.5
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• pp.783-790
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• 2016

Objectives: The purpose of this study is to evaluate the non-enzymatic antioxidants stabilities in dentifrices by ascorbic acid and tocopherol according to the chemical condition. Methods: For the analysis of two antioxidants, HPLC UV detector system was used. HPLC was performed using sodium sulfate, acetonitrile(ACN), methanol(MeOH) and measuring absorbance at 240-295 nm. To confirm general pH reaction of two compounds, buffer solution was prepared for the analysis. The dentifrice was titrated by pH so as to examine the change of elapsed time in dentifrice. Linearity of calibration curve of two antioxidants was measured. Results: Each compound showed good linearity at optimized wavelength as well as showing good precision. General pH reaction of two antioxidants was examined. Ascorbic acid showed the highest residue(63.23%) at pH 10 and the lowest residue(2.77%) at pH 4. Tocopherol showed the highest residue(55.70%) at pH 7 and the lowest residue(3.31%) at pH 4. As a result of changing elapsed time of antioxidants in dentifrice by pH, components were remained stably at low temperature($39.2^{\circ}F$) and pH 7. Conclusions: It is necessary to keep dentifrice including ascorbic acid and tocopherol, and non-enzymatic antioxidants at pH 7 and low temperature for improving chemical stability.

• The Journal of the Korean dental association
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• v.58 no.2
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• pp.68-82
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• 2020

Running title: Adequacy of dentist supply Objectives: The proper provision of dentists is very important for delivering the dental care that people need. The purpose of this study is to evaluate the adequacy of dentist supply and to predict the proper supply of dentists in Korea for the next 10 years. Methods and materials: Using the data from 2004 to 2017 in the Statictics Korea, the dental needs were measured as days of admission and the annual total dental care hours in 2020, 2023, 2026 and 2030 were predticted using regression analysis. The dental care productivity (average in-office hours) of dentists was analyzed using regression analysis including age, gender, education level and region as a confounder. The annual care hours were predicted according to seven scenarios based on the percentage of women among dentists, post-dentist education levels, the percentage of dentists in the metropolitan area, aging and retirement age. Results: The needed dentist based on the data in the Statictics Korea will be 27, 288 ~ 27, 311 in 2020, 28,104 ~ 28,1785 in 2023, 28,977 ~ 29,124 in 2026, and 30,174 ~ 30,413 in 2030. On the other hand, the number of dentists in Korea will be 26,945 in 2020, 28,813 in 2023, 30,682 in 2026 and 33,173 in 2030. The adequacy index of dentist supply will be -0.01 in 2020 to +0.10 in 2030. Conclusions: Our data showed that dentists will be adequately supplied in Korea for the next 10 years. Overall, the ratio between dentist versus 1,000 Koreans will be increased from 0.5 in 2019 to 0.7 in 2020, which will meet the mean of OECD countries.

• Journal of the Korean Society of School Health
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• v.22 no.1
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• pp.67-72
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• 2009

Purpose: The purpose of this study was to examine the relationship between the toothpaste squeezing methods and the amount of toothpaste that the daycare teachers apply for the children in order to prevent the overuse of fluoride-containing toothpaste among children, and to understand their educational experiences on oral health and their awareness of the right amount of toothpaste used. Methods: The subjects in this study were 87 teachers at 16 different daycare centers in the city of Sokcho, Gangwon Province. They were interviewed to find out whether they had ever received oral health education and whether they were cognizant of the right amount of toothpaste to be used. And a transverse technique and a pea-sized squeezing technique were selected to look for connections between their toothpaste squeezing methods and the amount of toothpaste used by them. Results: 89.7 percent of the daycare teachers investigated taught to preschoolers how to do toothbrushing after they took meals and had a snack. 36.8 percent of the daycare teachers had children squeeze toothpaste on their own. The amount of toothpaste applied by the daycare teachers at a time was 0.58ｇ. When they utilized two other squeezing methods, transverse technique and pea-sized squeezing technique, they used each 0.38 g (p<0.005) and 0.38 g (p=0.405) of toothpaste. Conclusion: To prevent children from being overly exposed to fluoride-containing toothpaste, daycare teachers should learn about the right amount of toothpaste to be used when oral health education is provided, and the transverse technique should be recommended to ensure the use of the proper amount of toothpaste.

• The korean journal of orthodontics
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• v.51 no.5
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• pp.346-354
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• 2021

Objective: To compare the effectiveness of ibuprofen, acetaminophen, and chewing gum for orthodontic pain relief and to assess if chewing gum can be a non-pharmacological alternative for orthodontic pain relief. Methods: The study enrolled 106 patients of both sexes, aged ≥ 12 years, with body weight > 50 kg, and mild-to-moderate dental crowding in the upper arch. After randomization and allocation concealment, the intervention groups were either administered with ibuprofen (400 mg) or acetaminophen (500 mg) or chewed sugar-free chewing gum immediately after initial archwire placement and every 6 hours for 1 week if the pain persisted. The control group did not receive any pain relief. The pain was assessed on a 100-mm visual analog scale at rest and while biting down at T1 (2 hours), T2 (24 hours), T3 (2 days), T4 (3 days), T5 (7 days), and T6 (21 days). Statistical analyses were performed using the Kruskal-Wallis and post-hoc Mann-Whitney U tests (α = 0.05). Results: The chewing gum group experienced more pain relief than the ibuprofen group at while biting down at T3 (p = 0.04) and at rest at T4 (p < 0.001). The chewing gum group reported more pain relief than the acetaminophen and control groups while biting down at T3 (p = 0.03 and p = 0.0006, respectively) and T4 (both p < 0.001). Conclusions: Chewing gum can be a non-pharmacological alternative for orthodontic pain relief at 2 and 3 days after initial archwire placement.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.42
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• pp.30.1-30.7
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• 2020

Background: Dental studies of precocious puberty have focused on examination of jaw and dentition growth. The aim of the study was to analyze the relationship between precocious puberty and maxillary dental developmental abnormalities (DDAs). Methods: This retrospective study was conducted on the Korean patients in whom dental panoramic and hand-wrist radiographs had been taken before they were 15 years of age. The maxillary DDAs were assessed as mesiodens, congenital missing teeth, peg-shape lateral incisors, or impacted teeth. The chronological ages of the control group members were within the normal range of the hand-wrist bone age. Others with a peak luteinizing hormone of ≥ 5 and < 5 IU/L were allocated to central precocious puberty (CPP) and peripheral precocious puberty (PPP), respectively. Results: Of the enrolled 270 patients, 195, 52, and 23 were allocated to the control, CPP, and PPP groups, respectively. The maxillary DDAs were significantly more prevalent in the CPP group than in the other groups. Among those with maxillary DDA, the mesiodens predominated. Age- and sex-adjusted multivariate analysis revealed maxillary DDA (odds ratio, 3.36; 95% CI, 1.60-7.05) and especially mesiodens (odds ratio, 5.52; CI, 2.29-13.28) to be significantly associated with CPP. Conclusions: Maxillary DDAs were significantly more prevalent in the CPP group than in the PPP or control groups. Among the many types of maxillary DDAs, mesiodens was significantly associated with CPP and may be considered a predictor of the development of CPP.