Estudio de la actividad antimicrobiana de Xenophyllum poposum sobre microorganismos de la cavidad bucal por el método de difusión radial / Study of the antimicrobial activity of Xenophyllum poposum on microorganisms of the oral cavity by the radial diffusion method

Resumen En este estudio se evaluó la actividad antimicrobiana in vitro de extractos de Xenophyllum poposum sobre microorganismos bucales como Streptococcus mutans, Streptococcus sobrinus, Lactobacillus casei, Actinomyces naeslundii, Actinomyces odontolyticus, Candida albicans y Veillonella sp. Se empleó el método de difusión radial en agar y como controles negativo y positivo de inhibición se emplearon etanol y clorhexidina al 0,12% (Plac out NF®) respectivamente. Los extractos con mayor actividad antimicrobiana fueron el etanólico y el clorofórmico. La diferencia entre ambos no fue estadísticamente significativa (p≥0,05). Tampoco se observó diferencia significativa con respecto a la clorhexidina, excepto sobre Veillonella sp., ya que el extracto etanólico presentó halos de inhibición significativamente menores sobre este microorganismo. Esto es importante ya que Veillonella se considera indicador de salud en relación a la caries dental. En base a esto, el extracto etanólico de Xenophyllum poposum podría ser usado como control químico de la biopelícula dental.

Abstract In this study, the in vitro antimicrobial activity of Xenophyllum poposum extracts on oral microorganisms such as Streptococcus mutans, Streptococcus sobrinus, Lactobacillus casei, Actinomyces naeslundii, Actinomyces odontolyticus, Candida albicans, Veillonella sp. was evaluated. The radial diffusion method in agar was used and 0.12% ethanol and chlorhexidine (Plac out NF®) were used as negative and positive inhibition controls, respectively. The extracts with the highest antimicrobial activity were the ethanolic and chloroform extracts. The difference between the two was not statistically significant (p≥0.05). No significant difference was observed with respect to chlorhexidine, except on Veillonella sp., since the ethanolic extract presented significantly lower inhibition halos on this microorganism. This is important as Veillonella is considered an indicator of health in relation to dental caries. Based on this, the ethanolic extract of Xenophyllum poposum could be used as chemical control of dental biofilm.

Resumo Neste estudo, a atividade antimicrobiana de extratos de Xenophyllum poposum sobre microrganismos orais como Streptococcus mutans, Streptococcus sobrinus, Lactobacillus casei, Actinomyces naeslundii, Actinomyces odontolyticus, Candida albicans e Veillonella sp. Foi utilizado o método de difusão radial em ágar e etanol 0,12% e clorexidina (Plac out NF®) como controles de inibição negativa e positiva, respectivamente. Os extratos com maior atividade antimicrobiana foram os extratos etanólico e clorofórmio. A diferença entre os dois não foi estatisticamente significativa (p≥0,05). Não foi observada diferença significativa em relação à clorexidina 0,12%, exceto em Veillonella sp., uma vez que o extrato etanólico apresentou halos de inibição significativamente menores neste microrganismo. Isso é importante, pois a Veillonella é considerada um indicador de saúde em relação à cárie dentária. Com base nisso, o extrato etanólico de Xenophyllum poposum pode ser utilizado como controle químico do biofilme dental.

The Clinical Pattern and Prevalence of Streptococcus mutans and Streptococcus sobrinus among Adult and Children Patients with Dental Caries

Abstract Objective: To explore the clinical pattern, host factors, and presentation of Streptococcus mutans related to caries incidence among children and adults visiting Universitas Airlangga dental clinic. Material and Methods: This was an observational study with a cross-sectional approach with 50 patients in each group of carious children (6-12 years) and adults (18-35 years). Dental decay samples were taken by sterile excavator, put in a BHI's transport medium, and directly incubated overnight at 37 ºC. The next day, they were sub-cultured microbiologically in Tryptone Yeast Cystine Sucrose Bacitracin (TYCSB) selective medium. Bacterial species and serogroups were examined by PCR. All patient's data were collected from medical records and direct observation. Results: Caries were mostly media type in both children and adults. Oral hygiene (OHIS) in children was higher than in adults but not significantly different according to their DMFT. The highest scores for decay, missed and filled teeth were 16, 8 and 7, with an average of 6.82, 1.22 and 0.63, considered quite high. Conclusion: The prevalence of S. mutans was higher in children's caries than in adults, but among the adult patients the co-incidence of S. mutans and S. sobrinus was associated with higher DMFT. The mutans serotypes e, f, and d were more prevalent among children than adults.

Modeling the Growth of Bacteria Streptococcus sobrinus Using Exponential Regression

Abstract Objective: To build an exponential regression model based on parameter estimation. Material and Methods: We developed a simple mathematical model to simulate the growth of bacteria and the exponential growth is often used to model population growth as such cell growth while the exponential decay is portraying a declining or decreases in the size of the population. An exponential regression method was used to fit the data and estimate growth parameter values Streptococcus sobrinus using statistical software SPSS version 20. Results: Based on the results of the parameter estimates, which is constant are 83.039 and b1 is 0.005 while R-square is 0.952. According to the R-Square results obtained, the model is good and appropriate. Conclusion: The model can be used to find the potential biological parameters, which may be able to predict the treatment outcome. This study helps researchers to understand the specific growth rate(s), which can be used to best grow the organism.

Relationship of Oral Bacterial Load Over One Year of Smoking Cessation / 치위생과학회지

BACKGROUND: Smoking exerts an adverse effect on the periodontal tissue by reorganizing the ecosystem of oral microorganisms and is considered to be an important factor in the development of periodontal disease. Although cross-sectional studies on smokers and non-smokers have been attempted to investigate the microbial differences in periodontal oral cavity, only few studies have been conducted to investigate the changes in oral microorganisms during smoking cessation. The purpose of this study was to investigate the changes of bacteria in saliva and gingival crevicular fluid (GCF) over a period of one year among 11 smokers trying to quit smoking.METHODS: Eleven smokers trying to quit smoking visited the clinic at baseline, two weeks, two months, four months, six months, and 12 months to give saliva and GCF samples. The amounts of 16S rRNA, Porphyromonas gingivalis, Treponema denticola, Prevotella intermedia, Fusobacterium nucleatum subsp. nucleatum, Streptococcus mutans, and Streptococcus sobrinus in saliva and GCF were quantified using real-time polymerase chain reaction TaqMan probe assay. The results were analyzed by nonparametric statistical analysis using Friedman test and Spearman correlation coefficient.RESULTS: After cessation of smoking, the amounts of 16S rRNA corresponding to P. gingivalis, F. nucleatum, P. intermedia, and T. denticola in saliva decreased and then again increased significantly. The amount of F. nucleatum 16S rRNA in GCF decreased significantly after smoking cessation. Positive correlations were observed between 16S rRNA and F. nucleatum and between F. nucleatum and T. denticola in saliva and GCF.CONCLUSION: Even if the number of subjects in this study was small, we suggest that smoking cessation may reduce the total bacterial amount and F. nucleatum in GCF. However, the results regarding changes in the microbial ecosystem due to smoking or smoking cessation were inconsistent. Therefore, further in-depth studies need to be carried out.

Antimicrobial and anti-caries effect of new glass ionomer cement on enamel under microcosm biofilm model

Abstract The occurrence of caries lesions adjacent to restorations is a serious problem in Dentistry. Therefore, new antimicrobial restorative materials could help to prevent recurrent carious lesions. This study evaluated the effect of a new glass ionomer cement (Ion Z) on the viability of a microcosm biofilm and on the development of enamel demineralization. Enamel samples were filled with the following materials (n=9): A) Ion-Z (FGM Ltda); B) Maxxion R (FGM Ltda); C) Ketac Fil Plus (3M ESPE) and D) no restoration (control). The samples were then exposed to human saliva mixed with McBain saliva (1:50) containing 0.2% sucrose for 14 days. The live and dead bacteria were quantified by fluorescence using a confocal laser-scanning microscope. The enamel demineralization was analyzed using transverse microradiography (TMR). The data were submitted to ANOVA/Tukey or Kruskal-Wallis/Dunn test (p<0.05). Ion Z induced a higher percentage of dead bacteria (60.96±12.0%) compared to the other groups (Maxxion R: 39.8±6.7%, Ketac Fil Plus: 43.7±9.71% and control 46.3±9.5%). All materials significantly reduced the average mineral loss compared to control (Ion-Z 25.0±4.2%vol, Maxxion R 23.4±8.0%vol, Ketac Fil Plus 30.7±7.7 and control 41.2±6.6%vol). Ion-Z was the only material able to significantly improve the mineral content at the surface layer (Zmax: 63.5±18.2%vol) compared to control (38.9±11.3%vol). Ion-Z shows antimicrobial potential, but its anti-caries effect was similar to the other materials, under this model.

Resumo A ocorrência de lesões de cárie adjacentes a restaurações é um sério problema na Odontologia. Portanto, novos materiais restauradores antimicrobianos poderiam ajudar a prevenir as lesões cariosas recorrentes. Este estudo avaliou o efeito de um novo cimento de ionômero de vidro (Ion Z) sobre a viabilidade de um biofilme microcosmo e o desenvolvimento da desmineralização do esmalte. Amostras de esmalte foram restauradas com os seguintes materiais (n=9): A) Ion-Z (FGM Ltda); B) Maxxion R (FGM Ltda); C) Ketac Fil Plus (3M ESPE) e D) sem restauração (controle). As amostras foram submetidas a uma mistura de saliva humana com saliva de McBain (1:50) contendo sacarose a 0,2% por 14 dias. As bactérias vivas e mortas foram quantificadas por fluorescência usando um microscópio confocal de varredura à laser. A desmineralização do esmalte foi analisada usando microradiografia transversal (TMR). Os dados foram submetidos aos testes ANOVA/Tukey ou Kruskal-Wallis/Dunn (p<0,05). O Ion Z induziu uma porcentagem mais elevada de bactérias mortas (60,96 ± 12,0%) comparado aos outros grupos (Maxxion R: 39,8 ± 6,7%, Ketac Fil Plus: 43,7 ± 9,71% e controle 46,3 ± 9,5%). Todos os materiais reduziram significativamente a perda mineral média em relação ao controle (Ion-Z 25,0 ± 4,2% vol, Maxxion R 23,4 ± 8,0% vol, Ketac Fil Plus 30,7 ± 7,7% vol e controle 41,2 ± 6,6% vol). O Ion-Z foi o único material capaz de melhorar significativamente o conteúdo mineral na camada superficial (Zmax: 63,5 ± 18,2% vol) em comparação com o controle (38,9 ± 11,3% vol). Ion-Z mostrou potencial antimicrobiano, mas seu efeito anti-cárie foi semelhante aos outros materiais, sob este modelo.

Antimicrobial Effect of Polyphenon 60 against Streptococcus mutans and Streptococcus sobrinus

Polyphenon 60 refers to the mixture of catechins present in green tea. The aim of this study was to investigate the antimicrobial activities of polyphenon 60 against 4 strains of Streptococcus mutans and 2 strains of Streptococcus sorbrinus, which are the major causative bacteria of dental caries. The minimum bactericidal concentration (MBC) values of polyphenon 60 for S. mutans and S. sobrinus were determined and the effect of biofilm formation inhibition of that was evaluated. The MBC value of polyphenon 60 against the bacterial strains was 2.5 mg/ml except for one particular strain, S. mutans KCOM 1128 for which the value was 1.25 mg/ml. The results of biofilm formation inhibition assay revealed that polyphenon 60 inhibited biofilm formation more than 90% at a concentration of 2.5 mg/ml. It was apparent that polyphenon exhibited biofilm formation inhibition activity along with bactericidal effect against S. mutans and S. sobrinus. Therefore, it is proposed that polyphenon 60 as one of the components of bactericidal agents could be useful in developing oral hygiene products, toothpaste or gargling solution.

Study of Bacteria Associated with Dental Caries Using a 3 Tone Disclosing Agent / 대한소아치과학회지

The aim of this study was to determine the efficacy of a 3 tone plaque disclosing gel in assessing the risk of caries related to the population of Streptococcus mutans, Streptococcus sobrinus, and Lactobacillus spp. quantified using a quantitative real-time polymerase chain reaction (qRT-PCR).15 healthy children of ages 9 – 12 years were randomly examined. The 3 tone plaque disclosing gel was applied on teeth surfaces, which changed the color to pink or red, blue or purple and light blue. Plaque was divided into 3 groups based on staining. Genomic DNA from each sample was subjected to a qRT-PCR assay for quantitative detection of target bacteria. The Kruskal-Wallis test was conducted for correlation between the color of plaque and the number of bacterial species.The levels of S. mutans, S. sobrinus, and Lactobacillus spp. were significantly different in the plaque samples of the 3 groups (p < 0.05). The proportion of S. sobrinus to S. mutans showed correlation to the color of plaque.The different color-dyed plaque was related to the number of acidogenic bacteria. The 3 tone plaque disclosing gel could be used as one of the indicators to assess the clinical risk of caries associated with the population of S. mutans, S. sobrinus, and Lactobacillus spp.

Antimicrobial Effect of Acanthopanax sessiliflorum Fruit Extracts against Selected Oral Bacteria / 치위생과학회지

This study aimed to evaluate the antimicrobial effects of Acanthopanax sessiliflorum fruit (ASF; Ogaza) extracts on Streptococcus mutans and Streptococcus sobrinus, which are agents that cause dental caries, and on Streptococcus mitis and Streptococcus salivarius, the microbial flora of the oral cavity. The ASF extracts obtained using 70% ethanol were fractionated in the order of ethyl acetate and n-Butanol, concentrated under reduced pressure, and lyophilized to give powdery solvent extracts. The antimicrobial activity of ASF extracts from each solvent was examined using the disk diffusion method. As a result, only those extracts obtained using an ethyl acetate solvent showed antimicrobial activity. These extracts were selected, and the minimum inhibitory concentration was measured by disk diffusion method at various extract concentrations. Results showed a minimum inhibitory concentration of 32 mg/ml. The viable cell count was measured to confirm the minimum bactericidal concentration. Results showed a minimum bactericidal concentration of 64 mg/ml. In the cytotoxicity test using normal human dermal fibroblast cells, the absorbance value of the test group was similar to that of the control group at 0.64, 1.28, and 6.4 mg/ml. The bacteria and their colonies were examined using a scanning electron microscope. Boundaries between the antimicrobial activity region and non-antimicrobial activity region were observed around the paper disk, which was immersed in the extract with 32 mg/ml concentration. Bacterial colonization was not observed in the area with antimicrobial activity. This finding suggests that ASF extracts can inhibit the growth of some microorganisms in the oral cavity, in addition to the effects of these extracts known to date. In particular, ASF extracts may be used as a preparation for preventing dental caries by adding the extract to the toothpaste or oral mouthwash.

Salivary density of Streptococcus mutans and Streptococcus sobrinus and dental caries in children and adolescents with Down syndrome

Abstract Streptococcus mutans and Streptococcus sobrinus are strongly associated with dental caries. However, the relationship between oral streptococci and dental caries in children with Down syndrome is not well characterized. Objective To assess and compare dental caries experience and salivary S. mutans, S. sobrinus, and streptococci counts between groups of Down syndrome and non-Down syndrome children and adolescents. Material and Methods This study included a sample of 30 Down syndrome children and adolescents (G-DS) and 30 age- and sex-matched non-Down syndrome subjects (G-ND). Dental caries experience was estimated by the number of decayed, missing, and filled teeth in the primary dentition and the permanent dentition. Unstimulated whole saliva samples were collected from all participants. The fluorescence in situ hybridization technique was used to identify the presence and counts of the bacteria. The statistical analysis included chi-square, Student's t-test and Spearman's correlation. Results The G-DS exhibited a significantly higher caries-free rate (p<0.001) and a lower S. mutans salivary density (p<0.001). No significant differences were found in the salivary densities of S. sobrinus or streptococci between the groups (p=0.09 and p=0.21, respectively). The salivary S. mutans or S. sobrinus densities were not associated with dental caries experience in neither group. Conclusion The reduced dental caries experience observed in this group of Down syndrome children and adolescents cannot be attributed to lower salivary S. mutans densities, as determined with the fluorescence in situ hybridization technique.

Antimicrobial effect of Prunus mume extracts against cariogenic bacteria / 대한구강보건학회지

OBJECTIVES: This study was conducted to determine whether Prunus mume extracts have an antimicrobial effect against Streptococcus mutans (S. mutans) and Streptococcus sobrinus (S. sobrinus). METHODS: The study used crushed and dried Prunus mume, to which 80% methanol was added to obtain extracts. The extracts then underwent a demarcation process, sequentially using hexane, chloroform, and ethyl acetate, all of which have different polarities, followed by a reduction in pressure . The disc diffusion method was then used to measure the clear zone diameter to identify the antimicrobial effect of Prunus mume extracts using the different solvents. The methanol extracts that presented antimicrobial activity against S. mutans and S. sobrinus were then selected, and their optical densities (3, 6, 9, 12, and 24 h after cultivation) were measured to identify growth retardation effects based on extract concentration (0.01, 0.1, 1, and 5 mg/ml). RESULTS: A clear zone was observed in methanol and ethyl acetate for S. mutans when the antimicrobial effect of Prunus mume extracts of each solvent against oral microorganisms was measured via the disc diffusion method. A clear zone was observed in hexane, chloroform, methanol, and ethyl acetate, when the extracts were tested for antimicrobial activity against S. sobrinus. The extract concentration of 1 mg/ml retarded growth with a statistical significance (P<0.05) from 6 h onwards, as determined when the optical density was measured hourly and the growth curves of S. mutans and S. sobrinus were plotted. CONCLUSIONS: Prunus mume extracts retarded the growth of S. mutans and S. sobrinus with increase in time and concentration. Therefore, Prunus mume extracts hold the potential to be used for developing an oral antimicrobial agent to control dental caries.

Characterization and antimicrobial efficacy of Portland cement impregnated with silver nanoparticles

PURPOSE: This study investigated the effects of silver nanoparticle (SN) loading into hydraulic calcium silicate-based Portland cement on its mechanical, antibacterial behavior and biocompatibility as a novel dental bone substitute. MATERIALS AND METHODS: Chemically reduced colloidal SN were combined with Portland cement (PC) by the concentrations of 0 (control), 1.0, 3.0, and 5.0 wt%. The physico-mechanical properties of silver-Portland cement nanocomposites (SPNC) were investigated through X-ray diffraction (XRD), setting time, compressive strength, solubility, and silver ion elution. Antimicrobial properties of SPNC were tested by agar diffusion against Streptococcus mutans and Streptococcus sobrinus. Cytotoxic evaluation for human gingival fibroblast (HGF) was performed by MTS assay. RESULTS: XRD certified that SN was successfully impregnated in PC. SPNC at above 3.0 wt% significantly reduced both initial and final setting times compared to control PC. No statistical differences of the compressive strength values were detected after SN loadings, and solubility rates of SPNC were below 3.0%, which are acceptable by ADA guidelines. Ag ion elutions from SPNC were confirmed with dose-dependence on the concentrations of SN added. SPNC of 5.0 wt% inhibited the growth of Streptococci, whereas no antimicrobial activity was shown in control PC. SPNC revealed no cytotoxic effects to HGF following ISO 10993 (cell viability > 70%). CONCLUSION: Addition of SN promoted the antibacterial activity and favored the bio-mechanical properties of PC; thus, SPNC could be a candidate for the futuristic dental biomaterial. For clinical warrant, further studies including the inhibitory mechanism, in vivo and long-term researches are still required.

Characterization and antimicrobial efficacy of Portland cement impregnated with silver nanoparticles

PURPOSE: This study investigated the effects of silver nanoparticle (SN) loading into hydraulic calcium silicate-based Portland cement on its mechanical, antibacterial behavior and biocompatibility as a novel dental bone substitute. MATERIALS AND METHODS: Chemically reduced colloidal SN were combined with Portland cement (PC) by the concentrations of 0 (control), 1.0, 3.0, and 5.0 wt%. The physico-mechanical properties of silver-Portland cement nanocomposites (SPNC) were investigated through X-ray diffraction (XRD), setting time, compressive strength, solubility, and silver ion elution. Antimicrobial properties of SPNC were tested by agar diffusion against Streptococcus mutans and Streptococcus sobrinus. Cytotoxic evaluation for human gingival fibroblast (HGF) was performed by MTS assay. RESULTS: XRD certified that SN was successfully impregnated in PC. SPNC at above 3.0 wt% significantly reduced both initial and final setting times compared to control PC. No statistical differences of the compressive strength values were detected after SN loadings, and solubility rates of SPNC were below 3.0%, which are acceptable by ADA guidelines. Ag ion elutions from SPNC were confirmed with dose-dependence on the concentrations of SN added. SPNC of 5.0 wt% inhibited the growth of Streptococci, whereas no antimicrobial activity was shown in control PC. SPNC revealed no cytotoxic effects to HGF following ISO 10993 (cell viability > 70%). CONCLUSION: Addition of SN promoted the antibacterial activity and favored the bio-mechanical properties of PC; thus, SPNC could be a candidate for the futuristic dental biomaterial. For clinical warrant, further studies including the inhibitory mechanism, in vivo and long-term researches are still required.

Effect of dietary sugars on dual-species biofilms of Streptococcus mutans and Streptococcus sobrinus – a pilot study / Efeito dos açucares da dieta em biofilme dupla espécie de Streptococcus mutans e Streptococcus sobrinus – um estudo piloto

Introduction: Frequent consumption of sugars and the presence of Streptococcus mutans and Streptococcus sobrinus are correlated with higher caries experience. Objective: The aim of this pilot study was to elucidate the effect of different fermentable carbohydrates on biomass formation and acidogenicity of S. mutans and S. sobrinus biofilms. Material and method: Single and dual-species biofilms of S. mutans ATCC 25175 and S. sobrinus ATCC 27607 were grown at the bottom of microtiter plates at equal concentrations for 24 h at 37 °C under micro-aerobic atmosphere. Carbohydrates were added at 2% concentration: maltose, sucrose, glucose and lactose. BHI Broth (0.2% glucose) was used as negative control. Acidogenicity was assessed by measuring the pH of spent culture medium after 24 h, immediately after refreshing the culture medium and for the next 1 h and 2 h. Crystal violet staining was used as an indicator of the total attached biofilm biomass after 24 h incubation. Data were analyzed by two-way ANOVA followed by Bonferroni post hoc test. Significance level was set at 5%. Result: All carbohydrates resulted in higher biomass formation in single- and dual-species biofilms when compared to the control group. Sucrose, lactose and maltose showed higher acidogenicity than the control group in both single- and dual-species biofilms after 24 h. Conclusion: These findings indicate that the type of biofilm (single- or dual-species) and the carbohydrate used may influence the amount of biomass formed and rate of pH reduction.

Introdução: O consumo frequente de açucares e a presença de Streptococcus mutans e Streptococcus sobrinus estão correlacionados com maior experiência de cárie. Objetivo: Elucidar o efeito de diferentes carboidratos fermentáveis na biomassa e acidogenicidade de biofilmes formados por S. mutans e S. sobrinus. Material e método: Biofilmes única e dupla- espécie de S. mutans ATCC 25175 e S. sobrinus ATCC 27607 em concentrações iguais cresceram no fundo de placas de microtitulação por 24 h a 37 °C em microaerofilia. Maltose, sacarose, glicose e lactose foram adicionados a 2%. BHI caldo (0.2% glicose) foi usado como controle negativo. Acidogenicidade foi avaliada por meio da medição do pH do meio de cultura após 24 h, imediatamente após troca de meio e nas próximas 1 h e 2 h. Coloração por cristal violeta foi usada como indicador do total de biomassa aderida, após 24 h de incubação. Os dados foram analisados por teste ANOVA two way e Teste de Bonferroni. O nível de significância foi de 5%. Resultado: Todos os carboidratos resultaram em maior formação de biomassa em ambos os tipos de biofilme (única ou dupla- espécie), quando comparado ao grupo controle. Sacarose, lactose e maltose mostraram maior acidogenicidade que o grupo controle após 24 h nos biofilmes única ou dupla-espécie, apenas após 24 h. Conclusão: Os achados indicam que o tipo de biofilme (única ou dupla- espécie) e o tipo de carboidrato usado podem influenciar tanto na quantidade de biomassa formada quanto na taxa de redução do pH.

Influence of surface roughness on oral streptococcal adhesion forces to dental filling materials / 华西口腔医学杂志

<p><b>OBJECTIVE</b>This study is to determine the common oral streptococcal adhesion forces by using composite resin and glass ionomer cement (GIC) with different degrees of surface roughness via atomic force microscopy (AFM) analysis. The influence of surface roughness on bacterial adhesion force is also discussed.</p><p><b>METHODS</b>Polishing and grinding were applied to obtain 300, 200, 100, and 10 nm surfaces of light-cured composite resin and GIC samples. Surface topography was assessed by AFM analysis. Initial colonizers (Streptococcus sanguinis and Streptococcus mitis) and cariogenic bacterial strains (Streptococcus mutans and Streptococcus sobrinus) were used to obtain bacteria-modified AFM probes. The force-distance curves were also measured by AFM analysis to determine the adhesion forces of bacteria on the surfaces of the composite resin and GIC. Material surface roughness was analyzed using ANOVA, and adhesion forces were subjected to nonparametric analysis (Kruskal-Wallis test). Comparison among groups was performed by Dunn's test. Material surface roughness and bacterial adhesion forces were subjected to correlation analysis.</p><p><b>RESULTS</b>Bacterial adhesion forces increased with increasing material roughness. The adhesion forces of the four bacterial species reached the maximum on the material surface of 300 nm. The adhesion force of Streptococcus mutans increased from 0.578 nN to 2.876 nN on GIC surfaces with 10 and 300 nm roughness. The adhesion forces of the four species on the surface of the composite resin were stronger than that of GIC. The initial colonizers exhibited stronger adhesion forces to different materials than the cariogenic strains. Intergroup differences were evident on the 200 and 300 nm material surfaces.</p><p><b>CONCLUSIONS</b>The surface roughness of the material significantly affected the bacterial adhesion forces, and a significant linear correlation existed between both factors. The bacterial adhesion forces of the GIC were lower than that of the composite resin. Furthermore, surface roughness exhibited less influence on the cariogenic strains than that on the initial colonizers.</p>

Development of Quantitative Real-Time PCR Primers for Detection of Streptococcus sobrinus

The purpose of this study was to develop Streptococcus sobrinus-specific qPCR primers based on the nucleotide sequence of the RNA polymerase β-subunit gene (rpoB). The specificity of the primers was determined by conventional polymerase chain reaction (PCR) with 12 strains of S. sobrinus and 50 strains (50 species) of non-S. sobrinus bacteria. The sensitivity of the primers was determined by quantitative real-time PCR (qPCR) with serial dilutions of the purified genomic DNAs (40 ng to 4 fg) of S. sobrinus ATCC 33478(T). The specificity data showed that the S. sobrinus-specific qPCR primers (RTSsob-F4/RTSsob-R4) detected only the genomic DNAs of S. sobrinus strains with a detection limit of up to 4 fg of S. sobrinus genomic DNA. Our results suggest that the RTSsob-F4/RTSsob-R4 primers are useful in detecting S. sobrinus with high sensitivity and specificity for epidemiological studies of dental caries.

Antimicrobial Effect of Coptidis rhizome Extract against Mutans Streptococci and Periodontopathogens

The purpose of the study was to investigate the antimicrobial activity of the methanol extract of Coptidis rhizome against the type strains of cariogenic bacteria, Streptococcus mutans and Streptococcus sobrinus, and the periodontopathogens, Porphyromonas gingivalis, Prevotella intermedia, Treponema denticola and Aggregatibacter actinomycetemcomitans. The antimicrobial activities of the crude extract and the methanol extract fractions of Coptidis rhizome separated by silica gel chromatography were evaluated by determining the minimal bactericidal concentration (MBC) values, using the microdilution method. The cell viability test of the extracts of Coptidis rhizome on the KB cells was also studied by methyl thiazolyl tetrazolium (MTT) assay. Our results showed that the 11th fraction (F11) of the methanol extract had the greatest antimicrobial activity against the tested bacteria, with no associated cytotoxicity on the KB cells, upto a concentration of 50 microg/ml. These results suggest that the silica gel chromatography fraction F11 of the methanol extract of Coptidis rhizome, could be useful in the development of oral hygiene products as an antimicrobial agent for the prevention of dental caries and periodontal diseases.

Effects of Yili dark bee propolis on oral cariogenic biofilm in vitro / 华西口腔医学杂志

<p><b>OBJECTIVE</b>To evaluate the effects of Yili dark bee propolis on the main cariogenic biofilm and mechanisms.</p><p><b>METHODS</b>Susceptibilities to the ethanolic extract of propolis against Streptococcus mutans (S. mutans), Streptococcus sobrinus (S. sobrinus), Streptococcus sanguis (S. sanguis), Actinomyces viscosus (A. viscosus), and Actinomyces naeslundii (A. naeslundii) were analyzed by crystal violet stain method to determine the minimum biofilm eradication concentration (MBEC). The biofilm was initially cultivated for 24 h. Subsequently, the propolis groups with different concentration MBEC and initial pH 7.0 were cultured for 24 h. Moreover, the pH value was measured to evaluate the acid-producing ability of the tested plaque biofilm. The effects of propolis on the insoluble extracellular polysaccharide synthesis of S. mutans biofilm were evaluated by anthrone method.</p><p><b>RESULTS</b>The MBEC of Yili propolis on S. mutans, S. sobrinus, S. sanguis, A. viscosus, and A. naeslundii were 6.25, 1.56, 3.13, 0.78, and 0.78 mg.mL-1, respectively. Propolis could decrease the ΔpH of the tested plaque biofilm, and the differences between the control and propolis groups were statistically significant (P<0.05). At MBEC, propolis could reduce the ability of S. mutans in synthesizing insoluble extracellular polysaccharides.</p><p><b>CONCLUSION</b>Yili propolis demonstrate remarkable eradicative effects on the cariogenic plaque biofilm, showing inhibition of the synthesis of biofilm-produced acids and insoluble extracellular polysaccharides.</p>

Analysis of caries susceptibility factors during transition from caries-free to caries in three-year-old children / 中华口腔医学杂志

<p><b>OBJECTIVE</b>To investigate the changes of caries susceptibility factors during the transition from caries-free to caries in three-year-old children.</p><p><b>METHODS</b>The study included 144 caries-free children aged 34-38 months. All participants underwent clinical examination and full-mouth supragingival plaque collection.Survey of children's oral health behaviors involving feeding habits and oral health care was also taken from children's parents of all participants. The children were reexamined 6 and 12 months later. According to the potential changes of caries status in twelve months follow up, all the participants were divided into three groups: caries-free group (caries free children in twelve months follow up), caries at 6-month group (children who were found with caries or cavities fillings at six months review) and caries at 12-month group (children who were caries free at six months but found with caries or cavities fillings at twelve months). Streptococcus mutans (Sm)and Streptococcus sobrinus (Ss) loads were compared among the three groups by real time fluorescence quantitative polymerase chain reaction (FQ-PCR).</p><p><b>RESULTS</b>One hundred and thirty children completed twelve months review, the dropout rate was 9.7% (14/144). At the end of twelve months follow up, the number of children in caries-free group, caries at 6-month group and caries at 12-month group was 58, 44 and 28 respectively. The changes of oral behavioral habits in caries-free group, caries at 6-month group and caries at 12-month group during twelve months follow up were not significantly different (P > 0.05). At baseline, the frequency of sweets consumption and eating sweets before sleeping in caries-free group was significantly lower than that in caries at 6-month group and caries at 12-month group (P < 0.001). At baseline, the quantity of Sm and Ss in caries at 6-month group[copy number of Sm: (6.33 ± 2.21)×10(3), copy number of Ss: (1.99 ± 0.45)×10(3)] was significantly higher than that in the caries-free group[copy number of Sm: (5.81 ± 2.43)×10(3), copy number of Ss: (1.34 ± 0.53)×10(3)] (P < 0.05). There was no significant difference in the quantity of Sm and Ss in the caries-free group and caries at 12-month group(P > 0.05). At six months, the quantity of Sm and Ss in caries at 12-month group was significantly higher than that in the caries-free group although both groups of children were caries-free at six months (P < 0.05).</p><p><b>CONCLUSIONS</b>The quantity of Sm and Ss increased six months before the caries onset in three-year-old children.High frequency sweets consumption and eating sweets before sleeping were important susceptibility factors for caries onset in the future.</p>

Synergistic effect of xylitol and ursolic acid combination on oral biofilms

OBJECTIVES: This study was designed to evaluate the synergistic antibacterial effect of xylitol and ursolic acid (UA) against oral biofilms in vitro. MATERIALS AND METHODS: S. mutans UA 159 (wild type), S. mutans KCOM 1207, KCOM 1128 and S. sobrinus ATCC 33478 were used. The susceptibility of S. mutans to UA and xylitol was evaluated using a broth microdilution method. Based on the results, combined susceptibility was evaluated using optimal inhibitory combinations (OIC), optimal bactericidal combinations (OBC), and fractional inhibitory concentrations (FIC). The anti-biofilm activity of xylitol and UA on Streptococcus spp. was evaluated by growing cells in 24-well polystyrene microtiter plates for the biofilm assay. Significant mean differences among experimental groups were determined by Fisher's Least Significant Difference (p < 0.05). RESULTS: The synergistic interactions between xylitol and UA were observed against all tested strains, showing the FICs < 1. The combined treatment of xylitol and UA inhibited the biofilm formation significantly and also prevented pH decline to critical value of 5.5 effectively. The biofilm disassembly was substantially influenced by different age of biofilm when exposed to the combined treatment of xylitol and UA. Comparing to the single strain, relatively higher concentration of xylitol and UA was needed for inhibiting and disassembling biofilm formed by a mixed culture of S. mutans 159 and S. sobrinus 33478. CONCLUSIONS: This study demonstrated that xylitol and UA, synergistic inhibitors, can be a potential agent for enhancing the antimicrobial and anti-biofilm efficacy against S. mutans and S. sobrinus in the oral environment.

Effects of adjunctive daily phototherapy on chronic periodontitis: a randomized single-blind controlled trial

PURPOSE: The purpose of this randomized single-blind controlled trial was to elucidate the clinical and antimicrobial effects of daily phototherapy (PT) as an adjunct to scaling and root planing (SRP) in patients with chronic periodontitis. METHODS: The study was conducted from December 2013 to May 2014 at Ewha Womans University Mokdong Hospital, Seoul, Korea. Forty-one patients with mild to moderate chronic periodontitis were randomly divided into two therapeutic groups in a 1:1 ratio: SRP+PT and SRP (control) groups. All participants underwent full-mouth SRP. PT was performed thrice a day for a month by using electric toothbrushes with embedded light-emitting diodes. Plaque index, gingival index, probing pocket depth (PPD), clinical attachment level (CAL), and bleeding on probing were assessed before (baseline) and four weeks after (follow-up) the treatment. Aggregatibacter actinomycetemcomitans, Porphyromonas gingivalis, Tannerella forsythia, Treponema denticola, Prevotella intermedia, Fusobacterium nucleatum, Parvimonas micra, Campylobacter rectus, Eikenella corrodens, Streptococcus mutans, and Streptococcus sobrinus levels were detected by a real-time polymerase chain reaction at the same points in time. RESULTS: The clinical parameters improved in both the groups. At the follow-up assessment, PPD was significantly decreased in the SRP+PT group (P=0.00). Further, PPD and CAL showed significantly greater changes in the SRP+PT group than in the SRP group (PPD, P=0.03; CAL, P=0.04). P. gingivalis and T. forsythia levels decreased in this group, but no significant intergroup differences were noted. CONCLUSIONS: Adjunctive PT seems to have clinical benefits, but evidence of its antimicrobial effects is not sufficient. Long-term studies are necessary to develop the most effective PT protocol and compare the effectiveness of PT with and without exogenous photosensitizers.