• Journal of the korean academy of Pediatric Dentistry
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• v.36 no.3
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• pp.440-447
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• 2009

This study was performed to compare the wear resistance of sealant and flowable resins for analyzing the effect of flowable resin as a sealant in preventive resin restorations. Specimens were made and Vicker's hardness number and surface roughness were measured. SEM observations of the polished and abraded surfaces were established. Kruskal-Wallis rank test and Mann-Whitney U test at the significant level of ${\alpha}$=0.05 were used. The following results were obtained: 1. The microhardness was decreased among groups in following order: Z350 (3M ESPE, U.S.A), Estelite (Tokuyama Dental, Japan) and Ultraseal (Ultradent, U.S.A). There were significant differences in all groups (p<0.0001). 2. The surface roughness was decreased among groups in following order: Ultraseal XT plus, Palfique Estelite LV and Filtek Z350 flowable. However, there is no statistically significant differences in roughness among Estellite, Z350 and Ultraseal at the significance level of ${\alpha}$=0.05, with p=0.116 3. SEM observation of the unworn and worn surfaces revealed the qualitative differences in the wear appearance among groups. The results in this study indicate that flowable resin is better than sealant in aspect of physical properties.

• Journal of the korean academy of Pediatric Dentistry
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• v.32 no.4
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• pp.634-643
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• 2005

The aim of this study is to evaluate the effects of blue light emitting diode (LED) Light Curing Units (FreeLight 2, L.E.Demetron I, Ultra-Lume 5) on the microhardness of three resin composites (Z250, Point 4, Dyract AP) and to determine their optimal curing time. Samples were made using acrylic molds $(2.0mm{\times}3mm)$ of each composite. All samples were prepared over a Mylar strip placed on a flat glass surface. After composite placement on the molds, the top surface was covered with another Mylar strip and a glass slab was gently pressed over it. The times of irradiation were as follows: Elipar TriLight, 40 s; Elipar FreeLight 2. L.E.Demetron I, and Ultra-Lume 5, 10s, 20s, 40s, respectively. Mean hardness values were calculated at the top and bottom for each group. ANOVA and Sheffe's test were used to evaluate the statistical significance of the results. Results showed that FreeLight 2, Ultra-Lume 5, and L.E.Demetron I were able to polymerize point 4 in 20 seconds to a degree equal to that of the halogen control at 40 seconds. FreeLight 2 and L.E.Demetron I were able to polymerize Z250 in 10 seconds to a degree equal to that of the halogen control at 20 seconds. FreeLight 2 and L.E.Demetron I were able to polymerize Dyract AP in 10 seconds to a degree equal to that of the halogen control at 40 seconds. The commercially available LED curing lights used in this study showed an adequate microhardness with less than half of the exposure time of a halogen curing unit.

• Journal of Korean society of Dental Hygiene
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• v.2 no.2
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• pp.175-186
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• 2002

Fluoride has been one of the most widely studied caries-preventive agents. But the effect of prenatal administration had been controversies for many years. The results showed that there were no influence on reproductive rate of rats with administration of fluoride from 0 to 20 ppm during pregnancy(p>0.05). There was a trend towards slightly increased the mean ash weight in the 1, 5 and 20 ppm groups, as compared with the control group. However, there was no significant differences among groups (p>0.05). The contents of calcium, magnesium and phosphorus in the total bone were increased with the administrated fluoride concentration were increased, but there were no statistically significant differences among groups(p>0.05). The mean fluoride level of 1 ppm group was significantly higher than that of control group, but the concentrations of fluoride in total carcass pups of 5 and 20 ppm groups were significantly less than that of 1 ppm group(p>0.05). The results of this study indicate that the amount of fluoride transferred to the offspring, which may produce anticariogenic effects in the primary teeth of their effects in the primary teeth of their offspring.

• Journal of Korean society of Dental Hygiene
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• v.10 no.1
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• pp.127-140
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• 2010

Objectives : The purpose of this study was to apply team-based learning to dental hygiene students in theoretical oral prophylaxis class, one of required courses geared toward acquiring professional knowledge on preventive public health, as oral prophylaxis was counted among major duties of dental hygienists. It's ultimately meant to compare the effects of team- based learning and expository instruction on the learning motivation and self-directed learning capabilities of learners in order to discuss the effects of team-based learning in dental hygiene education. Methods : The subjects in this study were 60 dental hygiene students at C college. Out of them, 32 students who were freshmen as of 2007 were grouped into an experimental group, and 28 students who were freshmen as of 2006 were selected as a control group. The experimental group was engaged in team-based learning from August 30 to December 6, 2007, and the control group took expository lessons from August 28 to December 8, 2006. Their learning motivation and self-directed learning capabilities were evaluated by using t-test, paired t-test and GLM analysis. Results : The findings of the study were as follows: 1. The experimental group scored better in learning motivation than the control group after they were engaged in team-based learning (p<.001). According to GLM analysis, there was a significant intergroup gap in learning motivation, and the two groups were statistically significantly different in its subfactors involving attention, relevance and confidence(p<.05). 2. The experimental group excelled the control group at self-directed learning capabilities(p<.05), and the team-based learning had a better effect on self-directed learning capabilities than the expository instruction. Conclusions : Given the findings of the study, the team-based learning was more effective than the expository instruction at boosting the learning motivation and self-directed learning capabilities of the students. Therefore revised teaching methods should be prepared in consideration of the characteristics of dental hygiene courses, and the development of new instructional models and educational programs is required as well.

• Journal of Korean society of Dental Hygiene
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• v.11 no.6
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• pp.833-841
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• 2011

Objectives : The purpose of this study was investigation of quality and quantity of nutritional intake related oral health status among Korean elders. Methods : The nutrient intake and the dietary quality was evaluated on the basis of the Dietary Reference Intakes For Koreans(KDRIs). Chi-square test for Complex Samples was used to determine the relationship between oral health and inadequate nutrient intake in Korean elders. The complex samples general linear model was used to test difference of average value difference of nutrient intake percentage compared to dietary reference intake(DRI), energy intake rate from three major nutrients, average mean adequacy ratio(MAR) and index of nutritional quality(INQ) related oral health status. Age, sex and total energy intake was compensated for this analysis. PASW 18 was used for statistical analysis. Results : We could found the difference of the nutrient intake and the dietary quality related oral health status among Korean elders. Especially, Nutrient intake percentage and component ratio of protein among energy intake rate from three major nutrient was lower as oral health status became worse. The percentage of subjects with nutritional intakes under showed highest level in worst oral health status. As oral health status became worse, average mean adequacy ratio(MAR) was lower and the number of nutrient of which index of nutritional quality(INQ) was under 1 was more. Conclusions : From the result above, this study clearly shows the level of oral health affecting the inequalities of eating and the food for the people. And the various propose of oral health policies is needed for vulnerable groups who needs solution to solve the problem of inequality of food distribution where intensive distribution of nutrition problem occurred. Sufficient, safe, and a variety of healthy food intake is a fundamental right of our people. And also, to apply this policy in reality, institutional arrangements and organizations, and specific performing system will be needed.

• Journal of Society of Preventive Korean Medicine
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• v.3 no.2
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• pp.79-89
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• 1999

This study was conducted to investigate the antitoxic component in aqueous extract of Houttuynia cordata $T_{HUNB}$. The results were as follows: Generally, detoxication effects by Houttuynia cordata $T_{HUNB}$ extract increased in proportion to the extract concentrations. When 40mg/kg dosage of Houttuynia cordata $T_{HUNB}$ extract was administered, it showed the highest antitoxic effects in metallothionein induction. After the extract treatment, body weights increased in proportion to the extract concentration. However, after 3 weeks, the body weight decreased insignificantly. From the above results, Houttuynia cordata $T_{HUNB}$ extract increased metallothionein concentration and decreased the toxicity of cadmium in rats.

• Journal of Korean society of Dental Hygiene
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• v.1 no.1
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• pp.63-76
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• 2001

This study was designed to evaluate the effects of music on dental pain and anxiety during ultrasonic scaling. One hundred and twenty five patients visited dental unit of Soonchunhyang University Chunan hospital for scaling were enrolled during August 1999 and February 2000. The patients were allocated randomly into two groups. music (n = 61) and control groups (n = 65). The music group patients listened to self-selected music using an earphone during scaling. Standardized questionnaire were used to assess the subjective denial pain and anxiety before and after scaling in both groups. In music group, more information on music effect was collected. To evaluate changes of physical signs by scaling, blood pressure and pulse were checked by a wrist check oscillometric. The results were as follows: 1. No significant difference in dental pain and anxiety between before and after scaling was observed in music group. However, the music group patients were satisfied with music because of reduction of pain(93.5%) and anxiety(93.4%), 96.7% of music subjects wanted to listen to music in next scaling. 2. While no significant difference in systolic blood pressure before scaling between music and control groups, systolic blood pressure of control group during scaling was significantly higher than that of music group(P<0.05). 3. In multiple logistic regression. the odds ratio(OR) of pain was decreased with age and female patients had higher OR (1.7, p>0.05). Patients with previous scaling experience complained of more dental pain during scaling than patients without experience. Music was not a significant predictor of denial pain during scaling, controlling for possible confounders. 4. While age. music. and scaling experience were not related to dental anxiety during scaling, sex and dental hygiene index were significant predictors of dental anxiety in multiple logistic regression. 5. Both during and after scaling. mean blood pressure of music patients were significantly lower than control patients after controlling for age, sex, and BMI. In conclusion, our data demonstrated that although listening to music did not disappear the dental pain and anxiety. but reduced the intensity of pain and anxiety during scaling. Furthermore, our data imply thai music has a effect of reduction of increasing blood pressure by scaling.

• Journal of Environmental Health Sciences
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• v.34 no.4
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• pp.261-270
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• 2008

Adjusted water fluoridation has been disputed because of its various effects on human health. Previous studies have been concerned with the difference in bone mineral density (BMD) between water fluoridated (WF) and none water fluoridated (NWF) districts. The aim of this study is to examine whether water fluoridation affects BMD. BMD was measured by dual energy X-ray absorptiometry (DXA). 386 adults(174 males and 212 females) in Ansan (WF) district and 399 adults (176 males and 223 females) in Sihwa (NWF) district, participated in this study. The Ansan and Sihwa districts are similar in residential environment and living class. The relationship between serum fluoride concentration and BMD was also examined by analysis of the serum fluoride concentrations from 402 inhabitants of the Ansan district. In females, the BMD of subjects living in Ansan ($0.457{\pm}0.008$) was a little higher than that of Sihwa subjects ($0.446{\pm}0.008$), although it is not significant, after adjusting for BMI, physical activity level, educational achievement, smoking volume, menopause status, and number of births. However, the BMD of Ansan subjects ($0.532{\pm}0.020$) in their forties was statistically higher than that of Sihwa (0.498{\pm}0.019). No relationship was found in males. In residential periods, there was significant difference (Ansan $0.467{\pm}0.013$, Sihwa $0.434{\pm}0.012$, p=0.0125) in the BMD between females of two districts, particularly in the group of over 6 year long-term inhabitants. On the contrary, there was no remarkable difference in males from the two districts. Serum fluoride concentrations in females were associated with BMD, especially in the age group of forties (p=0.0457). No relationship was observed in the male group. Analysis of adult BMD over the age of 20 in a water fluoridated and a none water fluoridated district, confirms more or less a higher BMD in the water fluoridated (WF) district, especially for females. It is assumed that the difference between two districts came somewhat from the effect of water fluoridation.

• Journal of dental hygiene science
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• v.15 no.2
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• pp.202-208
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• 2015

The aim of this retrospective study was to evaluate the relationship between periodontal health condition and the results of a new method such as Cariview which could evaluate the acidity of dental biofilms. Fifty four subjects more than 20 years old were selected for the candidates of this study. The periodontal health conditions of the candidates were divided into 4 groups according to the assessment of X-ray and Quantitative Light-induced Fluorescence-Digital (QLF-D; Inspektor Research Systems BV) images; gingivitis, slight periodontitis, moderate periodontitis, severe periodontitis. The biofilm acidogenicity of each subject was examined using Cariview (All in ONE BIO) according to manufacturer's instruction, and the Cariview score was calculated. The mean differences of Cariview score between 4 groups of periodontal health condition were examined by ANCOVA test with the covariance of decayed, missing, and filled teeth (DMFT) index. As a result, the mean Cariview score was different, however it was not significantly different from the 4 groups (p=0.12). The mean score was the lowest in the gingivitis group ($40.54{\pm}11.01$), and the highest in slight periodontitis group ($57.26{\pm}20.51$). In conclusion, the significant mean differences were not confirmed in Cariview score according to the periodontal health condition.

• Journal of Dental Rehabilitation and Applied Science
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• v.37 no.3
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• pp.123-129
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• 2021

Purpose: The purpose of this study was to investigate antifungal activity of shiitake mushroom yeast and hyphal type of Candida albicans. Materials and Methods: The extract from shiitake mushroom was collected by drying the supernatant after soaking shiitake mushrooms in water or ethanol. The antifungal activity of the extracts against yeast type of C. albicans was investigated by the susceptibility assay using microplate. C. albicans biofilm was formed on 12-well plate using Ham's F-12 medium in CO₂ incubator and treated with the ethanol extract. Furthermore, C. albicans biofilm was formed on denture base resin disk and treated with or without the ethanol extract in the presence of denture cleanser. Live C. albicans in biofilm was counted by cultured colony forming unit value after inoculated on agar plate. Results: Ethanol extract from shiitake mushroom showed stronger antifungal activity against yeast type of C. albicans compared to its water extract. The ethanol extract significantly reduced count of C. albicans in hyphal biofilm (P < 0.05). Also, the ethanol extract showed synergistically antifungal effect with denture cleanser on candidal biofilm on denture base resin disk (P < 0.05). Conclusion: The ethanol extract of shiitake mushroom may be a candidate for preventing candidal stomatitis as well as denture-related stomatitis.