Microplastic chip occurrence at toothbrush bristle tips:an optical microscopy investigation / 대한구강보건학회지

Objectives@#This study aimed to investigate the presence of microplastic chips at the tips of toothbrush bristles using optical microscopy. @*Methods@#Toothbrushes available in South Korea were tested. We randomly selected 12 toothbrushes, including four domestically produced and eight imported toothbrushes. Toothbrushes with tapered bristle ends were excluded. Toothbrushes with conventional bristle shapes based on visual inspection were included. Three identical toothbrushes were prepared. The outer bristles of each toothbrush were sampled using ScotchTM tape and prepared using a scalpel for optical microscopy.The inspector visually assessed both the bristle diameter and the presence of microplastic chips that remained attached to the ends of the toothbrush bristles under light microscopy (40× magnification). @*Results@#All toothbrush bristles met the criteria for soft bristles (diameters ranging from 0.2 to 0.25 mm). The incidence of microplastic chips varied among toothbrush bristles, ranging from a minimum of 3.6% to a maximum of 86.2%. Notably, toothbrushes with smaller diameter bristles exhibited higher levels of microplastic chips. @*Conclusions@#This study confirmed that the trimming conditions of toothbrush bristles and the occurrence of microplastic chips vary among different toothbrushes. Our findings suggest that toothbrush manufacturers need to improve their manufacturing processes to prevent the generation of microplastic chips during bristle trimming.

Comparison of interdental brush size and label information marketed in Korea / 대한구강보건학회지

Objectives@#This study compares the labeling information on the sizes of interdental brushes marketed in Korea to their actual sizes. Moreover, it analyzes the relationship between the size of the passage hole diameter (PHD), brush diameter, stem diameter, and stem length. @*Methods@#Among the commercially available interdental brushes in Korea, 171 interdental brushes, 3 in each size, were collected from 9 companies. The labels of the collected interdental brushes were researched, and the PHD was measured and compared. The correlation between the passage hole diameter, brush diameter, stem diameter, and stem length was analyzed. Multiple regression analysis was performed to verify the effect of brush diameter, stem diameter, and stem length on the determination of the PHD. @*Results@#The sizes of the interdental brushes were expressed using the ISO labeling or the Small, Medium, Large (S, M, L) labeling and indicated in units of 0.1. The concordance rate of the measured PHD and named PHD was 39.7%. The measured brush diameter, stem diameter, and stem length increased as the interdental brush size increased. There was a significant correlation (P<0.01) between PHD, brush diameter, stem diameter, and stem length. The order of variables with the most to least significant influence on PHD was stem diameter (β=0.528), brush diameter (β=0.404), and stem length (β=0.074). @*Conclusions@#This study shows that the label and actual size of interdental brushes did not match, and the concordance rate between the measured and labeled PHDs was low. Therefore, the interdental brush size labels among manufacturers should be standardized. Moreover, these manufacturers must provide the correct size information for the interdental brushes.

Evaluation of toothpaste abrasivity using acrylic and spectrophotometry / 대한구강보건학회지

Objectives@#This study aimed to develop a method for objectively evaluating toothpaste abrasivity, enabling a direct comparison between different toothpastes. @*Methods@#Nine commercially available toothpaste variants were selected, and 8 mm thick acrylic specimens were allocated to each toothpaste treatment group (n=7). A control group without toothpaste was also included. Specimens and toothbrushes were mounted on the V8 Cross brushing machine, and toothpaste (0.05-0.1 g) was applied for 20 strokes under a 200 g load and 1 Hz speed. The surface wear was measured at an absorbance of 600 nm in a UV-Vis spectrophotometer. Specimens were then photographed with a polarized light microscope, and the gray value of the worn brushed part was obtained through image analysis using Image J software. A one-way ANOVA followed by Bonferroni’s post-hoc test was employed for analyzing absorbance and gray value differences among the toothpaste groups. The correlation between absorbance and gray value was assessed using Pearson’s correlation analysis. @*Results@#Significant differences were noted in absorbance and gray values across the toothpaste groups (P<0.05), and a strong correlation was observed between the absorbance and the values from the images analyzed (r=0.948, P<0.001). The wear rankings based on absorbance and image analysis values were mostly the same. @*Conclusions@#This study introduces a direct and objective method for evaluating toothpaste abrasion, offering users objective information on different toothpaste types.

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.

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.

Prediction of dental caries in 12-year-old children using machine-learning algorithms / 대한구강보건학회지

OBJECTIVES@#The decayed-missing-filled (DMFT) index is a representative oral health indicator. Prediction of DMFT index is an important basis for the development of public oral health care projects and strategies for caries prevention. In this study, we used data from the 2015 Korean children's oral health survey to predict DMFT index and caries risk groups using statistical techniques and four different machine-learning algorithms.@*METHODS@#DMFT prediction models were constructed using multiple linear regression and four different machine-learning algorithms: decision tree regressor, decision tree classifier (DTC), random forest regressor, and random forest classifier (RFC). Thereafter, their accuracies were compared.@*RESULTS@#For the DMFT predictive model, the prediction accuracy of multiple linear regression and RFC were 15.24% and 43.27%, respectively. The accuracy of DTC prediction was 2.84 times that of multiple linear regression. The important feature of the machine-learning model, which predicts DMFT index and the caries risk group, was the number of teeth with sealants.@*CONCLUSIONS@#Using data from the 2015 Korean children's oral health survey, which is considered big data in the field of oral health survey in Korea, this study confirmed that machine-learning models are more useful than statistical models for predicting DMFT index and caries risk in 12-year-old children. Therefore, it is expected that the machine-learning model can be used to predict the DMFT score.

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.

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.

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.

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.

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.

Red fluorescence of oral bacteria is affected by blood in the growth medium / 대한구강보건학회지

OBJECTIVES: Dental plaque emits red fluorescence under a visible blue light near the ultra-violet end of the light spectrum. The fluorescence characteristics of each microorganism have been reported in several studies. The aim of this study was to evaluate changes in red fluorescence of oral microorganisms that is affected by blood in the culture media. METHODS: The gram-positive Actinomyces naeslundii (AN, KCTC 5525) and Lactobacillus casei (LC, KCTC 3109) and gram negative Prevotella intermedia (PI, KCTC 3692) that are known to emit red fluorescence were used in this study. Each bacterium was activated in broth and cultivated in different agar media at 37℃ for 7 days. Tryptic soy agar with hemin and vitamin K3 (TSA), TSA with sheep blood (TSAB), basal medium mucin (BMM) medium, and BMM with sheep blood (BMMB) were used in this study. Fluorescence due to bacterial growth was observed under 405-nm wavelength blue light using the quantitative light-induced fluorescence-digital (QLF-D) device. The red, green, and blue fluorescence values of colonies were obtained using image-analysis software and the red to green ratio (R/G value) and red to total RGB ratio (R/RGB value) were calculated for quantitative comparison. RESULTS: The QLF-D images of the AN, LC, and PI colonies showed red fluorescence in all media, but the fluorescence of all bacteria was reduced in TSA and BMM media, compared with in TSAB and BMMB media. Both the R/G and the R/RGB values of all bacteria were significantly reduced in growth media without blood (P<0.001). CONCLUSIONS: Based on this in vitro study, it can be concluded that red fluorescence of oral bacteria can be affected by growth components, especially blood. Blood-containing medium could be a significant factor influencing red fluorescence of oral bacteria. It can be further hypothesized that bleeding in the oral cavity can increase the red fluorescence of dental plaque.

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.

Red fluorescence of oral bacteria interacting with Porphyromonas gingivalis / 대한구강보건학회지

OBJECTIVES: Dental plaque is composed of 700 bacterial species. It is known that some oral microorganisms produce porphyrin, and thus, they emit red fluorescence when illuminated with blue light at a specific wavelength of <410 nm. Porphyromonas gingivalis belongs to the genus Porphyromonas, which is characterized by the production of porphyrin. The aim of this study was to evaluate red fluorescence emission of some oral microorganisms interacting with P. gingivalis. METHODS: Five bacterial strains (P. gingivalis, Streptococcus mutans, Lactobacillus casei, Actinomyces naeslundii, and Fusobacterium nucleatum) were used for this study. Tryptic soy agar medium supplemented with hemin, vitamin K3, and sheep blood was used as a growth medium. The fluorescence emission of bacterial colonies was evaluated under 405 nm-wavelength blue light using a Quantitative Light-induced Fluorescence Digital (QLF-D) camera system. Each bacterium was cultured alone and co-cultured in close proximity with P. gingivalis. The red/green (R/G) ratio of fluorescence image was calculated and the differences of R/G ratio according to each growth condition were compared using the Mann-Whitney test (P<0.05). RESULTS: Single cultured S. mutans, L. casei and A. naeslundii colonies emitted red fluorescence (R/G ratio=2.15±0.06, 4.31±0.17, 5.52±1.29, respectively). Fusobacterium nucleatum colonies emitted green fluorescence (R/G ratio=1.36±0.06). The R/G ratios of A. naeslundii and F. nucleatum were increased when P. gingivalis was co-cultured with each bacterium (P<0.05). In contrast, the R/G ratios of S. mutans and L. casei were decreased when P. gingivalis was co-cultured with each bacterium (P=0.002, 0.003). CONCLUSIONS: This study confirmed that P. gingivalis could affect the red fluorescence of other oral bacteria under 405 nm-wavelength blue light. Our findings concluded that P. gingivalis has an important role for red fluorescence emission of dental biofilm.

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 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.

Diagnostic predictability of self-reported questionnaire for periodontitis / 대한구강보건학회지

OBJECTIVES: The present study aimed to evaluate the validity of a set of self-reported questionnaires for periodontitis for estimating the prevalence of chronic adult periodontitis in the Korean population. METHODS: The questionnaire is comprised of a total of 14 questions with four summarized concepts including self-diagnosis of oral status, subjective signs related to oral health, smoking and drinking status, and use of auxiliary oral hygiene devices including scaling. The predictiveness of the measures from these self-reported questions was assessed by logistic regression modeling using receiver operating characteristic (ROC) statistics, sensitivity, and specificity. RESULTS: The sensitivity, specificity, and AUC including all questions were 0.571, 0.768, and 0.781, respectively; the sum of sensitivity and specificity was 1.34. To gain robustness, a simplified predictive model was built with six questions. Its results were 0.536, 0.817, and 0.762 for sensitivity, specificity, and AUC, respectively. The sum of sensitivity and specificity was found to be 1.35. CONCLUSIONS: The self-reported questionnaire for periodontitis showed considerable validity, but further study is required to provide optimal validity and predictability.

Evaluation of release of fluoride from dental varnishes marketed in Korea / 대한구강보건학회지

OBJECTIVES: The purpose of this study was to compare the amount and rate of cumulative fluoride released over a period of 4 h from several varnishes marketed in Korea. METHODS: The following six commercial products were studied: cavity shield (CS, 22,600 ppm F), V varnish (VV, 22,600 ppm F), enamel pro varnish (EP, 22,600 ppm F), MI varnish (MI, 22600 ppm F), fluorine care (FC, 22600 ppm F), and fluor protector N (FP, 7700 ppm F). Five samples were collected from each varnish. Further, 10 mg of each varnish were applied onto an acrylic surface (diameter, 5 mm) and then immersed in 20 mL of distilled water at 37degrees C. The fluoride concentration in each sample was then analyzed after 30 min, 1, 2, 3, and 4 h, and after 4 days of exposure. RESULTS: The cumulative amount of fluoride released by FC (5.64+/-1.10 ppm) was significantly higher than that released by other products after 30 min. FC (8.55+/-1.85 ppm) and MI (8.21+/-0.81 ppm) released a significantly higher cumulative amount of fluoride after 4 h. The cumulative rate of fluoride released by FC (47.80+/-9.35%) was significantly higher than that of other products after 30 min. FC (72.44+/-15.68%) and MI (69.54+/-6.88%) showed a higher cumulative fluoride release rate after 4 h. MI sustainably released fluoride after 4 h and demonstrated a high fluoride release rate of 95.76%. CONCLUSIONS: The cumulative amount and rate of fluoride released by several varnishes were statistically significant at each time point. This data can be used by clinicians prior to selection of dental products.

Cost-benefit analysis of a water fluoridation program for 11 years in Jinju, Korea / 대한구강보건학회지

OBJECTIVES: The aim of this study was to estimate the economic costs and benefits of a water fluoridation program in the city of Jinju, Korea. METHODS: In 2009, dental surveys were conducted on 2,315 children aged 6-12 years in Jinju, which had been fluoridated for 11 years. The decayed/missing/filled teeth (DMFT) scores of children in Jinju were compared to the DMFT scores of same-aged children in non-fluoridated small- and medium-sized cities in the fourth Korean National Health and Nutrition Examination Survey conducted from 2007 to 2009 by the Korea Centers for Disease Control and Prevention. The reduced number of decayed permanent teeth by the water fluoridation program was estimated as the difference between the DMFT scores of children in Jinju and those in non-fluoridated small- and medium-sized cities. The economic benefits were estimated by the savings from reduced dental treatment costs by using the reduced number of decayed permanent teeth from the water fluoridation program. All annual costs and benefits were calculated from 1998 to 2009. The social rate and untreated rate of decayed teeth were applied as 3% and 20%, respectively. The annual benefit-cost ratio was estimated by using the annual benefits and cumulative program costs. RESULTS: The economic benefit in 2009 from a water fluoridation program was estimated as 57,496,000,000 Korean Won (KRW), and the cumulative cost in 2009 was estimated as 1,387,000,000 KRW. The net present value in 2009 from a water fluoridation program was 56,109,000,000 KRW. The benefit-cost ratio in 2009 was estimated as 41.4. CONCLUSIONS: The economic benefit of a water fluoridation program in Jinju city was evaluated as excellent.