Risk factors related to periodontal health of adolescents / 대한구강보건학회지

Objectives@#The purpose of this study was to investigate the risk factors related to periodontal health in middle school and high school adolescents. @*Methods@#This study was conducted using data from the Sixth Korean National Health and Nutrition Examination Survey (KNHANES, 2013-2015). Among the 22,948 participants in the Sixth KNHANES, 1,222 participants (aged 12-18 years) who completed the systemic and oral health examinations and questionnaires were included in this study. Independent variables related to demographic socioeconomic status and oral health-related behaviors were the following: age, gender, household income, frequency of daily toothbrushing, smoking, alcohol drinking, annual dental visit, and periodontal treatment. The dependent variables were the prevalence of gingival bleeding or calculus and the number of sextants with gingival bleeding or calculus. @*Results@#Among the total participants, 34.1% were diagnosed with prevalence of gingival bleeding or calculus, and periodontal health was found to be at its worst at 17 years of age (41.6% of participants). Moreover, household income, alcohol drinking, annual dental visits, and frequency of daily toothbrushing were related to prevalence and the number of sextants with gingival bleeding or calculus. The adjusted odds ratio (aOR) for prevalence of gingival bleeding or calculus by alcohol consumption, toothbrushing less than twice per day, and number of DMFT were 5.00 (95% CI: 2.24-11.18), 2.21 (95% CI: 1.21-4.04), and 1.09 (95% CI: 1.02-1.17), respectively. @*Conclusions@#To prevent periodontal disease among adolescents, it is necessary to improve oral health-related behavior and its associated factors and continuous oral health education.

Preventive effect of a 18-year water fluoridation program for dental caries in a rural area of Korea / 대한구강보건학회지

Objectives@#The water fluoridation program in Hapcheon township area has been implemented since 2000. This study aimed to evaluate the caries-preventive effect of water fluoridation on permanent teeth after implementation of an 18-year community water fluoridation program in a suburban area. @*Methods@#A survey was conducted in 2018 with 359 subjects, aged 8, 10, and 12 years, residing in the Hapcheon township area. In this prospective cohort study, the data on caries prevalence obtained from 671 subjects, aged 8, 10, and 12 years, in 2000, when the community water fluoridation program was initiated in the township, were used as a cohort to evaluate the caries-preventive effect after 18 years. The caries-preventive effect of community water fluoridation on permanent teeth was estimated by comparison of the adjusted DMFT scores between the program and the control group, and between the pre- and post-program data after 18 years. The confounding factor, mean number of fissure-sealed teeth, was adjusted to estimate the caries-preventive effect of fluoridation on permanent teeth. @*Results@#Based on the results of the surveys conducted in Hapcheon-eup in 2000 and 2018, the mean number of fissure-sealed permanent teeth was 2.24 in 2000 and 1.38 in 2018. The mean DMFT scores of subjects aged 8, 10, and 12 years in 2018, adjusted for fissure-sealed permanent teeth in the fluoridated area, were significantly lower than those reported by the 2018 Korea National Children’s Oral Health Survey. In addition, the mean values of the adjusted DMFT scores of subjects aged 8, 10, and 12 years in 2018, after the 18-year fluoridation program, were significantly lower than those reported in 2000, the year the fluoridation program was initiated. @*Conclusions@#Community water fluoridation has a high caries-reducing effect; thus, the reintroduction of water fluoridation program is desirable to prevent dental caries.

Preventive effect of a 18-year water fluoridation program for dental caries in a rural area of Korea / 대한구강보건학회지

Objectives@#The water fluoridation program in Hapcheon township area has been implemented since 2000. This study aimed to evaluate the caries-preventive effect of water fluoridation on permanent teeth after implementation of an 18-year community water fluoridation program in a suburban area. @*Methods@#A survey was conducted in 2018 with 359 subjects, aged 8, 10, and 12 years, residing in the Hapcheon township area. In this prospective cohort study, the data on caries prevalence obtained from 671 subjects, aged 8, 10, and 12 years, in 2000, when the community water fluoridation program was initiated in the township, were used as a cohort to evaluate the caries-preventive effect after 18 years. The caries-preventive effect of community water fluoridation on permanent teeth was estimated by comparison of the adjusted DMFT scores between the program and the control group, and between the pre- and post-program data after 18 years. The confounding factor, mean number of fissure-sealed teeth, was adjusted to estimate the caries-preventive effect of fluoridation on permanent teeth. @*Results@#Based on the results of the surveys conducted in Hapcheon-eup in 2000 and 2018, the mean number of fissure-sealed permanent teeth was 2.24 in 2000 and 1.38 in 2018. The mean DMFT scores of subjects aged 8, 10, and 12 years in 2018, adjusted for fissure-sealed permanent teeth in the fluoridated area, were significantly lower than those reported by the 2018 Korea National Children’s Oral Health Survey. In addition, the mean values of the adjusted DMFT scores of subjects aged 8, 10, and 12 years in 2018, after the 18-year fluoridation program, were significantly lower than those reported in 2000, the year the fluoridation program was initiated. @*Conclusions@#Community water fluoridation has a high caries-reducing effect; thus, the reintroduction of water fluoridation program is desirable to prevent dental caries.

Molecular epidemiology and characterization of Streptococcus mutans strains in Korea / 대한구강보건학회지

OBJECTIVES: We investigated the characteristics of Streptococcus mutans in the national culture collection from Korea. Twenty-nine (dental plaque, n=27; endodontic infections, n=1; blood, n=1) isolates were included in this study.METHODS: Antimicrobial susceptibilities were tested using the disk diffusion test. Multilocus sequence typing (MLST), serotyping, and collagen-binding genes were used for polymerase chain reaction (PCR) and direct sequencing. A collagen-binding (to assess the adhesion properties) assay was performed. S. mutans demonstrated high susceptibility to antimicrobial agents. Differences in collagen-binding abilities of the cnm-positive and -negative groups were compared using the Mann-Whitney U test (P<0.05).RESULTS: MLST analyses revealed 25 sequence types (STs), 17 of which (ST213-ST229) contained new alleles. The strains were classified into four serotypes with the c type encompassing 79.3% of all strains, while the e, f, and k types representing 6.9% each. Analysis of the cnm and cbm genes, which encode the two surface adhesin components of S. mutans, revealed three cnm-positive strains, each displaying greater adhesion ability than those of the cnm-negative strains.CONCLUSIONS: This study highlights the presence of a wide variety of S. mutans genotypes in Korea. These findings may provide useful information regarding the pathogenesis of infectious diseases, such as dental caries.

In vitro fluoride release from five different fluoride varnishes / 대한구강보건학회지

OBJECTIVES: This study aims to compare the fluoride-release between different fluorine varnish under in vitro experimental conditions.METHODS: In this study, 5 fluoride varnish products distributed in Korea were selected. V-varnish™ (Vericom, Korea: VV), CavityShield™ (3M ESPE, USA: CS), Clinpro™ White varnish™ (3M ESPE, USA: CP), MI Varnish™ (GC, Japan: MI), and Fluor Protector (Ivoclar Vivadent, Liechtenstein: FP). For the in vitro study, 10 mg of each fluoride varnish was thinly applied to the same area of the specimen. The specimen was then immersed in 3 ml of distilled water at consistent intervals to confirm fluoride release. Nine specimens per group were used. Fluoride ion electrodes were used to measure the fluoride concentration of the solution. The Kruskal-Wallis nonparametric test was performed to compare between each experimental group, and the Wilcoxon signed-rank nonparametric test was performed to compare experimental groups over time. The significance level for a Type I error was set at 0.05. All statistical analyses were performed using SPSS 25.0 (IBM Co., Armonk, NY, USA).RESULTS: In vitro experiments showed that the amount of fluoride released from MI was higher than the other groups during the first 12 hours after application. However, the amount of fluoride released from CP and CS was higher than MI as the immersion time increased over 12 and 20 hours, respectively. The fluoride release from FP was the lowest at all measurement points.CONCLUSIONS: The results of this study showed that the remaining fluoride effect from rosin type fluoride varnishes was higher than liquid type fluoride varnishes. There were differences in the residual fluoride concentrations despite each fluoride varnish having the same fluoride content.

Elucidating the relationship of gingivitis and dental calculus with the periodontal health of 12-year-old children / 대한구강보건학회지

OBJECTIVES: This study aimed to investigate factors related to the periodontal health of 12-year-old children.METHODS: In 2015, the Korean Children's Oral Health Survey from the Ministry of Health & Social Welfare conducted a nationwide representative sample comprised of 23,702 12-year-old children. The calibration-trained dentists examined the gingivitis and dental calculus of the children taking into consideration of the Löe and Silness gingival index to diagnose gingivitis with a modified gingivitis scale. We used questionnaires to collect data from the children on dental treatments, the experience of dental pain and gingival bleeding, self-perceived oral health, and oral health behaviors. Data were analyzed using a complex samples Chi-square test, general linear model, and logistic regression. Significance was determined at P < 0.05.RESULTS: The prevalence of gingivitis was higher among males (OR 1.57), among children with poor perception (OR 1.19), dental calculus (OR 3.68), or gingival bleeding experience (OR 2.00), and among children not using dental floss (OR 1.69) or tongue cleaner (OR 1.90). The prevalence of dental calculus was higher among children with gingivitis (OR 3.82) and among children who had not visited a dental clinic in the preceding year (OR 1.31). However, dental calculus was lower among children with a higher frequency of daily toothbrushing (OR 0.75), intake of cariogenic foods (OR 0.90), or a higher DMFT index (OR 0.91).CONCLUSIONS: Children with dental calculus and gingival bleeding who did not visit a dental clinic in the preceding year also had a higher prevalence of gingivitis and dental calculus. The prevalence of children's dental calculus was lower among children with a high frequency of daily toothbrushing.

Association between components of metabolic syndrome and periodontitis in Korean adults aged 35–79 years / 대한구강보건학회지

OBJECTIVES: The purpose of this study was to investigate the association between the components of metabolic syndrome (MetS) (waist circumference, hyperglycemia, hypertriglyceridemia, low levels of high-density lipoprotein cholesterol, and hypertension) and periodontitis in Korean adults aged 35–79 years. METHODS: In this study, data from the Sixth Korean National Health and Nutrition Examination Survey (KNHANES, 2013–2015) were analyzed. Among the 22,948 participants of the Sixth KNHANES, 8,314 participants, who were aged 35–79 years and had completed all systemic and oral health examinations and questionnaires, were included in this study. Confounding variables associated with the demographics and socioeconomic status and systemic and oral health-related behaviors were age, gender, household income, the educational level, smoking and drinking habits, the physical activity status, and frequency of daily toothbrushing. The independent variables were components of MetS, and the dependent variable was periodontitis. RESULTS: Periodontitis was diagnosed in 37.0% of the participants. The incidence of periodontitis among participants with MetS was 47.9%. The incidences of periodontitis among participants with three, four, and five components of MetS were 44.8%, 50.0%, and 56.2%, respectively. The odds ratio (OR) for periodontitis among participants with MetS was 1.43 (95% confidence interval [CI]: 1.27–1.61). The participants with three, four, and five components of MetS showed a significantly higher OR for periodontitis than those with no components of MetS (three components, OR=1.18, 95% CI: 1.02–1.36; four components, OR=1.34, 95% CI: 1.14–1.59; five components, OR=1.68, 95% CI: 1.29–2.20). CONCLUSIONS: A higher number of components of MetS augments the OR of periodontitis.

Impact of incivility experienced by dental hygienists on organizational achievement-as a mediating effect of emotional exhaustion / 대한구강보건학회지

OBJECTIVES: Workplace incivility is experienced by dental hygienists, who perform a variety of tasks and roles in dentistry. Therefore, to enhance the performance of dental and medical institutions, it is necessary to identify dental hygienists experiencing incivility that affects the organizational performance. METHODS: Over a two-month period from May 1 to June 30, 2015, dental hygienists from 30 dental and medical institutions in Busan, the North and South Gyeongsang Provinces, Daegu, Seoul, and the Gyeonggi Province were convenience sampled. Data, from a total of 344 participants, were analyzed using the SPSS and AMOS statistical analysis software. RESULTS: Emotional exhaustion had a partial mediating effect on the relationship between patient incivility and job performance, a full mediating effect in relation to job satisfaction, and a partial mediating effect on the association with turnover intention. Meanwhile, emotional exhaustion had a full mediating effect on the relationships between superior incivility and job performance, as well as turnover intention, while a partial mediating effect in relation to job satisfaction. CONCLUSIONS: An in-depth review of interventions that can enable a mutually respectful working environment, and promote a healthy culture among dental hygienists in dental and medical institutions is needed.

Evaluation of oral health-related quality of life in orthodontic patients using the modified Oral Impact on Daily Performance (OIDP) questionnaire / 대한구강보건학회지

OBJECTIVES: This study evaluated oral health-related quality of life (OHQoL) before and after orthodontic treatment (orthodontic-tx) using the modified Oral Impact on Daily Performance (OIDP) questionnaire. METHODS: Ninety-six subjects (32 males, 64 females; 48 ranging between 12–17 years, 48 ranging between 18–29 years) who completed orthodontic-tx in two dental clinics in Busan from May to December 2013 participated in this study. The participants self-reported their OHQoL on the Korean translated version of the OIDP before and during orthodontic-tx when the brackets were removed from their teeth. The OHQoL was again measured 1 month later. The visual analogue scale (VAS) from 0 (never) to 10 (definitely yes) was used to quantify the OHQoL. The physical, psychological, and social effects of the orthodontic-tx on daily performance were analyzed according to age and gender. RESULTS: The OHQoL score was lower during the orthodontic-tx (7.49±0.19) than before (5.51±0.18), but the final OHQoL score, after orthodontic-tx (9.39±0.07), was higher than the score before treatment. The trend was the same over all sub performances. Before orthodontic-tx, the OHQoL score related to psychological performance (6.98±0.22) was the lowest compared to physical and social performance. During orthodontic-tx, the scores related to physical performance, especially in the older (0.7 times) and female (0.62 times) groups, decreased the most compared to before treatment. Psychological performance, especially in the older (1.81 times) and female (1.66 times) groups, increased the most after orthodontic-tx. CONCLUSIONS: This study confirmed that orthodontic-tx affects the OHQoL according to age and gender. Specific approaches, classified by age and gender, are needed to improve the quality of life of orthodontic dental patients.

Caries reduction effect of permanent teeth from community water fluoridation program for 17 years in Jinju city / 대한구강보건학회지

OBJECTIVES: The community water fluoridation program was implemented in 1998 in Jinju city. The aim of the present study was to evaluate the effect of this 17-year community water fluoridation program on caries reduction in permanent teeth. METHODS: Evaluation surveys were conducted in 2015 on subjects aged 8, 10, 12, and 15 years in Jinju city. The examined dental data were compared with that of subjects of the same age groups living in the medium-sized cities from the 6th Korea National Health and Nutrition Examination Survey (KNHANES) (2013–2015). The total number of subjects was 1,026 in Jinju city and 453 in the control group. The odds ratio of caries experience rate and untreated tooth rate on permanent teeth in Jinju city compared to control group was estimated based on the differences in DMF and untreated teeth rates after adjusting for gender, age, and mean number of fissure-sealed teeth. The effect of community water fluoridation program on caries reduction in permanent teeth was estimated by the differences in adjusted DMFT scores between the program and control groups. RESULTS: The odds ratio of caries experience rate and untreated tooth rate on permanent teeth in Jinju city compared to control group was estimated as 0.501 and 0.178, respectively. The effect of community water fluoridation program on caries reduction in permanent teeth was estimated as 40.0%. CONCLUSIONS: These results suggested that the effect of community water fluoridation program on caries reduction in permanent teeth in Jinju city was so high that similar programs should be developed in other regions in Korea.

Fluoride content of bottled water available in South Korea / 대한구강보건학회지

OBJECTIVES: The market for bottled water is increasing steadily in South Korea. Bottled water contains several naturally occuring minerals, such as calcium, magnesium, sodium, and fluoride. Fluoride is proven to be effective in preventing dental caries. In South Korea, the maximum permissible concentration of fluoride is 2 ppm for bottled water and 1.5 ppm for tap water. The aim of this study was to investigate the fluoride content of different commercially available brands of bottled water in South Korea, and compare the measured fluoride concentration to the concentration written on the label of each brand of bottled water. METHODS: Twenty-seven of the 59 different brands of bottled water produced in South Korea were investigated in this study. Three bottles of each brand were purchased from supermarkets, marts, and convenience stores in each region of Korea in August 2016. For each bottled water brand, the fluoride content was measured three times using a fluoride-ion selective electrode (Orion ionplus Fluoride Electrode 9609, Orion Research, USA). The calibration curve was generated using 0.2 and 2 ppm standard solutions, and confirmed using a 1 ppm standard solution. RESULTS: The mean fluoride content of the 27 brands of bottled water was 0.374±0.332 mg/L (range=0.040 to 1.172 mg/L). The fluoride content was labeled by the manufacturer, on each of the tested brands of bottled water. In eight brands, the labeled fluoride content differed from the experimental data. The minimum to maximum fluoride content measured from 10 brands showed a variation of 0.3 mg/L or more when compared to the labeled fluoride content. CONCLUSIONS: This study investigated the fluoride content of various brands of bottled water produced in South Korea and compared the measured fluoride levels with fluoride information on the bottle labels. To ensure that consumers are suitably informed regarding their exposure to fluoride, correct labelling of fluoride content in bottled water is important.

Ethanol changes atpB gene expression and proton permeability in Streptococcus mutans / 대한구강보건학회지

OBJECTIVES: As a first step to study the anticaries effect of ethanol alone, we investigated the effects of ethanol on the expression levels of the atpB gene and proton permeability of Streptococcus mutans in suspension cultures. METHODS: S. mutans UA159 was grown in brain heart infusion medium at either pH 4.8 or 6.8. The total extracted RNA was reverse-transcribed into cDNA using a Superscript™ First-Strand Synthesis System. The resulting cDNA and negative controls were amplified by ABI PRISM 7700 real-time PCR system with SYBR Green PCR Master Mix. For proton flux assay, bacterial suspensions were titrated to pH 4.6 with 0.5 M HCl, and then additional 0.5 M HCl was added to decrease the pH values by approximately 0.4 units. The subsequent increase in pH was monitored using a glass electrode. Ten percent (v/v) butanol was added to the suspensions at 80 min to disrupt the cell membrane. RESULTS: In a concentration-dependent manner, ethanol alone not only decreased the growth rate of S. mutans and the expression of the atpB gene but also increased the proton permeability at both pH 4.8 and 6.8. CONCLUSIONS: These findings suggest that ethanol has the potential for an anticaries ingredient. We believe that ethanol may be used together with fluoride and/or other cariostatic agents in order to develop better anticaries toothpastes and/or mouthrinses.

Periodontal health status of adolescents aged 15 years in Jinju city / 대한구강보건학회지

OBJECTIVES: The purpose of this study was to evaluate the periodontal status of adolescents aged 15 years in Jinju city. METHODS: The study subjects were 506 adolescents aged 15 years in Jinju city. We investigated the prevalence and severity of periodontal disease using the Community Periodontal Index (CPI) recommended by the WHO. Data on the frequency of daily tooth-brushing were collected through self-reported questionnaires. The information obtained on both the periodontal health status and frequency of daily toothbrushing of adolescents in Jinju city was compared with the data from the 6th Korea National Health and Nutrition Examination Survey 2013-2015 (KNHANES-VI). The software utilized in the analysis was SPSS version 23. Statistical significance was set at P < 0.05. RESULTS: The rate of healthy periodontal status in Jinju city was lower compared to KNHANES-VI (57.7% versus 63.7%). The rate of gingival bleeding in Jinju city and KNHANES-VI was 11.3% and 10.8%, respectively. The rate of calculus in Jinju city and KNHANES-VI was 31.0% and 25.6%, respectively. The rates of gingival bleeding and calculus were not significantly different between Jinju city and KNHANES-VI. The healthy periodontal segments in Jinju city were more than those in KNHANES-VI (5.43 versus 5.25). The bleeding periodontal segments in Jinju city were less than those in KNHANES-VI (0.25 versus 0.45). However, the periodontal segments with calculus in Jinju city were not significantly different from those of KNHANES-VI (0.31 versus 0.30). The frequency of daily tooth-brushing in Jinju city was more than that in KNHANES-VI (2.67 versus 2.47). CONCLUSIONS: These findings suggest that appropriate oral health education should be widely conducted to promote periodontal health in adolescents.

Survey of Oral Health Education Effects in Twenties / 대한소아치과학회지

The purpose of this study was to improve efficacy of oral health education in children and adolescents based on the experience and perception of oral health education in young adults who graduated from high school within 10 years.Questionnaires were given to 412 people, and among them, 388 completed survey forms were selected. The questionnaire included categories which examined one's experience and perception of oral health education, oral health knowledge, dental history, and oral health behavior.The results showed that the respondents perceived elementary school as the most effective period of oral health education. Oral examination with direct explanation was the most preferred method of oral health education, but web search was the main source of oral health information. And knowledge of fluoride and sealant about caries preventive effect was still lacking. Considering these results, oral examination with direct explanation and web search would be useful to improve efficacy of oral health education in children and adolescents.

Comparison of traditional dental plaque indices with real stained plaque area / 대한구강보건학회지

OBJECTIVES: The aim of this study was to compare Plaque Percent Index (PPI), calculated by Patient Hygiene Performance Index (PHPI), Rustogi's modification of the Navy Plaque Index (RMNPI), and the Quigley & Hein Plaque Index (QHPI), with visual assessment. METHODS: Ninety-six subjects, aged between 30–65 years, were examined; twenty subjects were included in the final analysis. The subjects' teeth were stained and photographed. Dental coloring and intraoral camera photography were performed by a single examiner. The oral images obtained were analyzed using Image J to measure the area of dental plaque. The values of PHPI, RMNPI, and QHPI were calculated twice. Statistical analyses were performed using descriptive statistics, chi-square test, and Pearson's correlation coefficient. RESULTS: The results of the correlation analyses of PPI with PHPI, QHPI, and RMNPI were as follows: for PHPI, the correlation coefficient (r)=0.584; for QHPI, r=0.689; and for RMNPI, r=0.729. Further, the kappa indices of PHPI, QHPI, and RMNPI were 0.810, 0.677, and 0.590 respectively. CONCLUSIONS: Among RMNPI, QHPI, and PHPI dental plaque indices, RMNPI and QHPI showed a high degree of correlation with the actual stained dental plaque area; on the other hand, PHPI showed the highest kappa index.

The caries preventive effect on permanent teeth adjusted for number of fissure-sealed teeth and surfaces from 6-year community water fluoridation program in Geoje City / 대한구강보건학회지

OBJECTIVES: The water fluoridation program has been implemented since 2008, in a region of Geoje City. This study aimed to evaluate the effectiveness of the water fluoridation program on caries prevention in the permanent dentition. METHODS: Evaluation surveys were conducted on 8-, 10- and 12-year-old children in the fluoridated and non-fluoridated regions of Geoje City, in 2015. The survey included 834 children from the fluoridated regions and 703 from the non-fluoridated regions. The data obtained from the survey were analyzed using the IBM SPSS statistical package version 23.0. The effectiveness of community water fluoridation in caries prevention was estimated by the differences in the decayed, missing, filled teeth (DMFT) and decayed, missing, filled surfaces (DMFS) scores, between the program and control groups. The mean numbers of fissure-sealed teeth and surfaces were adjusted to reduce their confounding effect. RESULTS: The mean DMFT and DMFS scores (0.69 and 0.91, respectively) of 10-year-olds from the fluoridated regions, after adjusting for the numbers of fissure-sealed teeth and surfaces, were significantly lower than those of the 10 year olds (DMFT: 0.95, DMFS: 1.32) from the non-fluoridated regions. The effectiveness of water fluoridation on caries prevention in the permanent dentition, estimated based on the differences in the mean DMFT and DMFS scores, adjusted for the number of fissure-sealed teeth and surfaces, between the program and control groups of 10-year-old children, was 27.4% and 31.1%, respectively. CONCLUSIONS: These results suggest that the effectiveness of water fluoridation on caries prevention in the permanent dentition, in Geoje City was so high that this program should be implemented in other regions in Korea as well.

The growth inhibitory effect of some vegetable oils on Streptococcus mutans and Lactobacillus casei / 대한구강보건학회지

OBJECTIVES: The purpose of this study was to evaluate the growth inhibitory effects of some vegetable oils on Streptococcus mutans (S. mutans) and Lactobacillus casei (L. casei). METHODS: Two bacterial strains and 5 kinds of test solutions (3 experimental groups: orange essential oil, olive oil, soybean oil; 1 positive control group: chlorhexidine solution; 1 negative control group: broth medium) were used in this study. S. mutans and L. casei pellets were exposed to 1 ml of one of the test solutions for 1 minute. Then, the treated bacterial cells were incubated in fresh broth medium for 0, 4, 8, 16, and 24 hours. The optical density of the broth medium was measured using an ELISA reader at 620 nm. A nonparametric Kruskal-Wallis test (with Mann-Whitney U tests) was performed to compare the change in optical density between different groups at different time points. RESULTS: Bacterial growth was significantly inhibited in all experimental groups compared to the negative control group. The growth of L. casei was less affected by experimental oils than that of S. mutans. Orange essential oil had the maximum growth inhibitory effect on S. mutans up to 8 hours, similar to that in the positive control group (P<0.01). Experimental oils had greater growth inhibitory effect on L. casei than chlorhexidine solution. CONCLUSIONS: This in vitro study confirmed the growth inhibitory effect of some vegetable oils on S. mutans and L. casei. Rising of the mouth using these vegetable oils is expected to have an anti-plaque effect, but additional clinical studies are needed to confirm this.

Caries-preventing effects of a suburban community water fluoridation program on permanent dentition after adjusting for the number of fissure-sealed teeth / 대한구강보건학회지

OBJECTIVES: The aim of this study is to evaluate the effect of suburban community water fluoridation programs on preventing caries in permanent teeth. METHODS: In 2012, surveys were administered to children aged 8, 12, and 15 years residing in fluoridated Habcheon township area. Samples collected during the national survey in 2012 from children of the same age residing in non-fluoridated township areas were used as the control, and the caries prevalence data from this sample were used to estimate the caries preventive effect in the studied regions. This study included 457 subjects from the Habcheon township area and 1,792 in the control group. The data obtained from the survey were analyzed using the IBM SPSS statistical package version 21.0. The caries preventive effect exerted by fluoride in the community water supply was determined by calculating the differences in the DMFT and DMFS indices between the study and control groups. The cofounders of the mean number of fissure-sealed teeth and surfaces were controlled to estimate the effectiveness of caries prevention. RESULTS: The odds ratio of subjects with no dental caries in the fluoridated region was 0.75 compared to that in the control group. The mean DMFT scores or DMFS scores adjusted for the number of fissuresealed teeth or tooth surfaces were lower than those in the control group. The caries prevention fraction was estimated to be 23.4% based on the difference in the adjusted mean DMFT scores between the control and study groups. CONCLUSIONS: These results suggest that fluoridation of the community water in the suburban area was highly effective in preventing dental caries in permanent teeth, and therefore, this community water fluoridation program should be implemented in other regions in Korea.

The pH-dependent effects of combining ethanol with fluoride on proton permeability in Streptococcus mutans / 대한구강보건학회지

OBJECTIVES: The aim of this research was to determine the pH-dependent changes in F-ATPase activity and proton fluxes in Streptococcus mutans (S. mutans) as induced by varying the concentration of fluoride ±10 mM (0.058% (v/v)) ethanol. METHODS: S. mutans UA159 was grown in Brain Heart Infusion medium at pH 4.8, 6.8, or 8.8. The F-ATPase assay was initiated by the addition of ATP, and stopped by adding 10% trichloroacetic acid. For the proton flux assay, bacterial suspensions were titrated to pH 4.6 with 0.5 M HCl, and then 0.5 M HCl was added to decrease the pH values in units of approximately 0.4 pH. The subsequent increase in pH was monitored using a glass electrode. To disrupt the cell membrane, 10% (v/v) butanol was added to the suspensions after 80 minutes. RESULTS: At all pH levels, fluoride ±10 mM ethanol not only decreased F-ATPase activity but also increased the proton permeability of S. mutans. The largest effects were observed at pH 4.8. Ethanol enhanced these effects only at pH 4.8. CONCLUSIONS: A very low concentration of ethanol enhanced the action of fluoride on F-ATPase activity and the proton permeability in S. mutans at acidic pH levels. We expect that low concentrations of ethanol may be used together with fluoride and/or other anticaries agents to develop more effective anticaries preparations.

Residents' opinions on the introduction of water fluoridation program in the district of Namdong water treatment plant, Incheon Metropolitan City / 대한구강보건학회지

OBJECTIVES: This study details a survey taken to ascertain the residents' opinions on the introduction of a community water fluoridation program (WFP) at the water treatment plant in the district of Namdong, Incheon Metropolitan City. METHODS: This cross-sectional study was conducted by a specialized institution and was based on a public opinion poll. The views of 1,000 adults who had lived in the district where tap water was supplied by the Namdong water treatment plant, Incheon were collected over a 1-year period. The dependent variable was the assent of the WFP. The independent variables were demographic and socioeconomic characteristics (sex, age, education, residence period, and income), awareness of WFP, drinking and cooking water, and decisional organization of WFP introduction. Statistical analysis was performed using chi-squared test with SPSS statistics 23.0 (SPSS Inc., Chicago, IL, USA). Variables related to the approval of the WFP were analyzed using a multivariate logistic regression model. One hundred and twenty-seven respondents who selected 'doesn't matter' were excluded. The significance level was set at α=0.05. RESULTS: The responses citing approval for the introduction of WFP comprised 58.7%, while the 'dissent' group accounted for 28.6%, and 12.7% stated that it does not matter. Respondents citing approval who were in the age group beyond fifties accounted for 66.0%; further, 67.6% of respondents aware of the WFP were in favor of the approval for WFP introduction. The decision to undertake water fluoridation was favored by the Regional Head and city council. There were no significant differences in the assent of WFP based on the respondents' sex, education level, job, and drinking and cooking water. The strongest correlation was observed between the awareness of WFP and the approval rate for WFP. CONCLUSIONS: To promote the introduction of WFP, active measures are required for educating people regarding effectiveness of caries prevention and safety of WFP.