Oral health condition according to distribution of periodontopathic bacterial complex / 대한구강보건학회지

OBJECTIVES: The purpose of this study was to evaluate the association between the distribution of periodontopathic bacteria and oral conditions.METHODS: Stimulated saliva was collected from 162 adults aged 60 years and above. The prevalence and amount of periodontopathic bacteria in the saliva were analyzed using real-time PCR. Pocket depth and clinical attachment loss were examined to evaluate the oral conditions of the subjects. Patients who had at least one tooth surface involved, with a pocket depth ≥4 mm or clinical attachment loss ≥5 mm were classified as having periodontal disease.RESULTS: The detection rates of most bacteria in the orange and green complexes were more than 90%, while those of P. gingivalis and T. forsythia in the red complex were 58.6% and 61.7%, respectively. The number of bacteria in the red complex positively correlated with each other. There were no significant differences in the number of types of red complex bacteria in the saliva and the distribution of residual number of teeth and periodontal disease (P>0.05). On the other hand, the number of remaining teeth in subjects with higher bacterial density were more than those with lesser bacterial density. In addition, the occurrence of dental disease differed significantly depending on the number of P. gingivalis and T. forsythia.CONCLUSIONS: The relative amount of periodontopathic bacteria is important in the occurrence of periodontal disease, and the number of these bacteria positively correlated with each other.

Effects of Diospyros kaki peel, Momordica charantia, and Canavalia gladiata extracts on the cariogenic traits of Streptococcus mutans / 대한구강보건학회지

OBJECTIVES: The purpose of this study is to determine methods of dental caries prevention by investigating the use of compounds of Diospyros kaki (D. kaki) peel, Momordica charantia (M. charantia), and Canavalia gladiata (C. gladiata) extracts to limit the cariogenic traits of Streptococcus mutans (S. mutans), such as their ability to proliferate and adhere to the tooth surface. METHODS: Broth microdilution and the agar spreading assay were used to determine the antimicrobial effect and minimum inhibitory concentration (MIC) of S. mutans extracts. In order to identify the adhesive ability of S. mutans at varying concentrations, culture plates were first stained with 1 ml of 0.01% crystal violet for 15 minutes at room temperature, and then eluted with 1 ml of EtOH:Acetone (8:2) solution for 15 minutes in a 37℃ incubator. Eluted solutions were then evaluated by use of a spectrophotometer at 575 nm. RESULTS: Experiments were conducted in order to investigate the effectiveness of D. kaki peel, M. charantia, and C. gladiata extracts on limiting the proliferation of S. mutans. The MIC was measured as an indication of whether the antibacterial activity of D. kaki peel, M. charantia, and C. gladiata extracts had a significant bacteriostatic effect on S. mutans. M. charantia extract was effective for growth inhibition on S. mutans at a minimum concentration of 0.25%. From the adhesion ability assay, M. charantia extract had an anti-adhesive effect. CONCLUSIONS: These results indicate that M. charantia extract demonstrates antibacterial activity and has an anti-adhesive effect on S. mutans. Due to these properties, M. charantia extract may be used to prevent dental caries.

Effects of a whitening strip combined with a desensitizing primer on tooth color / 대한구강보건학회지

OBJECTIVES: The purpose of this study was to evaluate the efficacy of a 2.9% hydrogen peroxide (HP) whitening strip with a desensitizing agent as a primer. METHODS: This study was approved by the Institutional Review Board of Kyungpook National University Hospital. A total of 144 subjects (mean age: 21.7 years) were recruited after they provided informed consent for participation in the study. All participants used the whitening strip and primer for 1.5 h a day for 14 days. ShadeEye-NCC and Vita classical shade guide were used to determine the color changes, with respect to baseline, after 1, 3, 5, 7, and 14 days. A self-administered questionnaire was used to collect data on satisfaction after bleaching and irritating symptoms during the 14 days. All collected data were analyzed with repeated measures ANOVA and one-way ANOVA using SPSS 20.0 for windows. RESULTS: Brightness (ΔL*) was significantly higher in groups 2 and 3 than in the control group after 3 days of the experiment. Chroma (Δb*) started to decrease in groups 2 and 3, compared to control, after 1 day. Perceived symptoms of irritation were significantly lower in groups using the strip combined with the desensitizing primer than in the control group. Satisfaction after bleaching was higher in the experimental groups than in control. CONCLUSIONS: The HP whitening strip with a desensitizing agent as a primer is clinically effective in bleaching human enamel after 3 days of use. It also reduces the prevalence of gingival irritation.

Validity and reliability of a questionnaire for evaluating periodontal disease / 대한구강보건학회지

OBJECTIVES: The purpose of this study was to develop a self-administered questionnaire survey to determine its validity and reliability as well as to improve the instructions for measurement of periodontal disease during oral examination for reliably calculating the prevalence of periodontal disease. METHODS: The data obtained was analyzed using SPSS 20.0 and the WINSTEPS program that employs the Rasch model to evaluate validity and reliability of the instrument. RESULTS: We developed a self-administered questionnaire survey consisting of 14 questions based on NHANES. We confirmed the reliability by testing and re-testing the questionnaire survey using selfadministered methods. The average Kappa index obtained was 0.73, which indicated a relatively high reliability. CONCLUSIONS: Reliability and validity of the self-administered assessment tool for periodontal disease developed for the local situation/circumstances of Korea is suitable to be applied for oral examination of a large population. Moreover, the questionnaire survey for periodontal disease could be used to acquire data for constructing a database for oral health policy development.

Relationship between periodontal status and chronic obstructive pulmonary disease / 대한구강보건학회지

OBJECTIVES: The aim of this study was to examine the relationship between periodontal health and chronic obstructive pulmonary disease (COPD) in a Korean population. METHODS: The Community Periodontal Index (CPI) data of 7,264 subjects, aged over 25 years, who participated in the Fourth Korea National Health and Nutrition Examination Survey was used to assess the periodontal status of the population. Severity of COPD in the subjects was classified according to the Global Initiative for Chronic Obstructive Lung Disease (GOLD) definition. RESULTS: Subjects with more severe COPD were more likely to have severe periodontal disease. After adjustment for gender, age, monthly income, education, economic activity, and occupation, the odds ratio of COPD was 1.18 (95% Confidence interval [CI], 0.63-2.21) for severe periodontal disease in the study sample. When stratified by smoking status, the odds ratio of current smokers was 0.92 (95% CI, 0.41-2.05) and that of non-smokers was 1.29 (95% CI, 0.64-2.59). CONCLUSIONS: Periodontal health was not significantly related to the severity of the COPD, even though smoking was a common risk factor. This is the first study examining the relationship between periodontal health and COPD in a Korean population. Studies that further investigate the causal relationship between the two are recommended.

Impact of amalgam removal on urinary mercury concentration in children: a pilot study / 대한구강보건학회지

OBJECTIVES: This pilot study aimed to evaluate the effect of dental amalgam, a restorative material, on children by measuring the mercury concentration in the urine as well as the number of teeth filled with dental amalgam. METHODS: Twenty children enrolled in grades 1-4 of two elementary schools in Daegu participated in this study. One trained dentist performed oral examinations and removed amalgam restorations from the teeth with a high and low speed handpiece. In order to measure the urinary mercury concentrations, urine samples were collected from all participants at baseline and immediately and 24 hours after removal of the dental amalgam restorations. RESULTS: The mean number of teeth from which the amalgam restorations was removed was 9.8 while the mean urinary mercury concentrations at baseline, immediately, and 24 hours after removal of dental amalgam restorations were 2.66, 2.76, and 2.76 microg/g creatinine, respectively. The mean urinary mercury concentration increased consistently after amalgam restoration removal. For those participants whose removed amalgamated surfaces were more than 11, the mean urinary mercury concentration immediately after amalgam restoration removal and 24 hours after removal increased consistently but showed no significant difference. CONCLUSIONS: This study demonstrated that dental amalgam restoration was related to urinary mercury concentration, and these findings present a possibility of mercury accumulation in the body. Therefore, we suggest future longitudinal studies to ensure the safety of children exposed to mercury by establishing criteria for amalgam removal.

Comparison of mRNA expression of gtf genes and adhesive ability of xylitol-sensitive and -resistant Streptococcus mutans by xylitol-treated concentrations / 대한구강보건학회지

OBJECTIVES: Xylitol is an effective anticarious natural sugar substitute, by inhibiting the virulence of Streptococcus mutans (S. mutans). However, long-term xylitol consumption leads to an emergence of the xylitol-resistant (XR) strains. This study aimed to confirm the general characteristics, mRNA expression of gtf genes, and adhesive ability of the xylitol-sensitive (XS) and XR S. mutans , by xylitol-treated concentrations. METHODS: S. mutans KCTC3065 was maintained in TYE medium, containing 0.4% glucose with 1% xylitol for 30 days at 37degrees C, 10% CO2 to form XR strain and the same procedures, without xylitol, were repeated for the formation of XS S. mutans. Both XS and XR were cultured by xylitol-treated concentrations (0%, 0.1% and 1%), then, general characteristics, such as growth and acid production, mRNA expression of gtf genes and adhesive ability were analyzed. RESULTS: Xylitol reduced the cell growth of XS S. mutans in a dose-dependent manner, but did not reduce the XR. Xylitol inhibited acid production of XS in a dose-dependent manner. However, it did not inhibit that of XR. Xylitol reduced the gtfB and gtfD mRNA expression of the XS S. mutans, which the genes synthesized soluble and insoluble extracellular polysaccharides, but not reduced that of the XR. By a microtiter plate assay, biofilm formation was more reduced in the XR strains, which means biofilm's adhesive ability of XR S. mutans was lower than that of the XS. CONCLUSIONS: These results indicate that a lower level of adhesive ability for XR S. mutans is related with mRNA expression level of gtf genes, which suggested that the XR strains may be less cariogenic than that of the XS.

Gene expression profile analysis of xylitol-sensitive and xylitol-resistant Streptococcus mutans in 0.5% glucose containing TYE media using DNA chip / 대한구강보건학회지

OBJECTIVES: Streptococcus mutans (S. mutans) is the major causative bacteria in dental caries. Xylitol is an effective anticarious natural sugar substitute by inhibiting the virulence of S. mutans. However, long-term xylitol consumption leads to the emergence of the xylitol-resistant S. mutans (XR). The aim of this study is to analyze the difference of gene expression profile of xylitol-sensitive S. mutans (XS) and XR in 0.5% glucose containing TYE media, using a DNA chip. METHODS: S. mutans KCTC3065 was maintained in 0.5% glucose and 1% xylitol containing TYE media, during 30 days at 37degrees C 10% CO2 to form XR. The same procedures without xylitol were repeated for the formation of XS. Both XS and XR were cultured in 0.5% glucose with or without 1% xylitol containing TYE media overnight and total RNA was extracted. RNA from XS was labeled with Cy-3 dye as control, and XR were labeled with Cy-5 as references. DNA chip was hybridized for 18-20 h at 42degrees C. RESULTS: A total of 277 genes of DNA chip data were significantly increased or decreased in XR. There is a total of 174 XR up-regulated genes in 0.5% glucose and 1% xylitol containing TYE media, and a total of 103 down-regulated genes. For compare with results of DNA chip, 11 in up-regulated genes and 10 in down-regulated were verified by RT-PCR. The most abundant increased genes in XR were related to cell envelope, cellular processes, DNA metabolism, transcription, and protein folding and stabilization. The decreased genes in XR were related to amino acid biosynthesis, toxin production and resistance, energy metabolism, ribosomal proteins synthesis, and signal transduction. CONCLUSIONS: These results indicate that the difference of gene expression profile of XS and XR may be in existence. In particular, results of this study for XR up-regulated genes have a lot of similarities with the already published xylitol-related researches and other functional studies.

Analysis of Cellular Changes Resulting from Forced Expression of Dickkopf-1 in Hepatocellular Carcinoma Cells / Journal of the Korean Cancer Association, 대한암학회지

PURPOSE: Recent studies have shown that Dickkopf-1 (DKK-1) is overexpressed in some tumors, including hepatocellular carcinoma. However, the role of increased DKK-1 in these tumors is not known. In this study, the DKK-1 expression in hepatocellular carcinoma (HCC) cell lines was evaluated and the effect of DKK-1 overexpression in HCC cell lines was studied. MATERIALS AND METHODS: The expression of DKK-1 in hepatocellular carcinoma cell lines was evaluated by RT-PCR. Stable cell lines that overexpressed DKK-1 were established. Cell growth, adhesion, migration and invasion assays were performed. RESULTS: RT-PCR analysis showed that 5 out of 8 HCC cell lines expressed DKK-1. The forced expression of DKK-1 suppressed the growth of cells and increased the population of cells in the sub-G1 phase. In addition, DKK- 1 reduced the cellular adhesion capacity to collagen type I and fibronectin, and it increased migratory capacity. However, overexpression of DKK-1 did not increase the invasion capacity of the HCC cell line. CONCLUSION: Collectively, our data suggest that overexpression of DKK-1 affects the biology of HCC cells.

Cloning of BNIP3h, a member of proapoptotic BNIP3 family genes

Apoptosis is regulated by interaction of antiapoptotic Bcl-2 family proteins with various proapoptotic proteins, several of which are also members of the Bcl-2 family. BNIP3 (formerly NIP3) is a proapoptotic mitochondrial protein classified in the Bcl-2 family based on limited sequence homology-3 (BH3) domain and COOH-terminal transmembrane domain. Sequence comparison of BNIP3 has indicated that there are several BNIP3 human homologs of this protein, like BNIP3L, Nix and BNIP3. We have cloned a new member of BNIP3 family from the cDNA library prepared from human dermal papilla cells and designated as BNIP3h. BNIP3h shows substantial homology with other BNIP3 family proteins. BNIP3h induced apoptosis from 24 hours after transfection in MCF7 cell lines and its apoptosis inducing activity is extended until 72 hours after transfection.