Abstract Objective This study aimed to evaluate the cytotoxicity and synergistic effect of epigallocatechin gallate (EGCG) and fosfomycin (FOSFO) on biofilms of oral bacteria associated with endodontic infections. Methodology This study determined minimum inhibitory and bactericidal concentration (MIC/MBC) and fractionated inhibitory concentration (FIC) of EGCG and FOSFO against Enterococcus faecalis, Actinomyces israelii, Streptococcus mutans, and Fusobacterium nucleatum. Monospecies and multispecies biofilms with those bacteria formed in polystyrene microplates and in radicular dentin blocks of bovine teeth were treated with the compounds and control chlorhexidine (CHX) and evaluated by bacterial counts and microscopy analysis. Toxicity effect of the compounds was determined on fibroblasts culture by methyl tetrazolium assays. Results The combination of EGCG + FOSFO demonstrated synergism against all bacterial species, with an FIC index ranging from 0.35 to 0.5. At the MIC/FIC concentrations, EGCG, FOSFO, and EGCG+FOSFO were not toxic to fibroblasts. EGCG+FOSFO significantly reduced monospecies biofilms of E. faecalis and A. israelli, whereas S. mutans and F. nucleatum biofilms were eliminated by all compounds. Scanning electron microscopy of multispecies biofilms treated with EGCG, EGCG+FOSFO, and CHX at 100x MIC showed evident biofilm disorganization and substantial reduction of extracellular matrix. Confocal microscopy observed a significant reduction of multispecies biofilms formed in dentin tubules with 84.85%, 78.49%, and 50.6% of dead cells for EGCG+FOSFO, EGCG, and CHX at 100x MIC, respectively. Conclusion EGCG and fosfomycin showed a synergistic effect against biofilms of oral pathogens related to root canal infections without causing cytotoxicity.

Abstract The present study evaluated the ability of Bifidobacterium and Lactobacillus species associated with streptococci to increase insoluble extracellular polysaccharide (EPS) production and initial caries lesion progression. Bovine enamel blocks (n = 190; 4 mm x 4 mm) were prepared, selected according to initial surface hardness (SH), and divided into two groups: a) double combinations: S. mutans with Bifidobacterium or Lactobacillus, and b) triple combinations: S. mutans and S. sobrinus with Bifidobacterium or Lactobacillus species. The blocks were exposed to the bacterial associations for 7 days. Subsequently, quantity of EPS from biofilms and caries lesion depth were determined by means of colorimetric and cross-sectional enamel hardness (ΔKHN) analysis. The data were submitted to one-way analysis of variance, followed by the Bonferroni test (p < 0.05). S. mutans with B. animalis or B. dentium produced a higher quantity of EPS; S. mutans + B. animalis led to the highest ∆KHN. S. mutans + S. sobrinus + B. longum induced greater EPS and ∆KHN values. In conclusion, associations of B. animalis and B. longum with streptococci promoted EPS production and caries lesion progression.

Abstract Porphyromonas gingivalis is one of the most important Gram-negative anaerobe bacteria involved in the pathogenesis of periodontitis. P. gingivalis has an arsenal of specialized virulence factors that contribute to its pathogenicity. Among them, fimbriae play a role in the initial attachment and organization of biofilms. Different genotypes of fimA have been related to length of fimbriae and pathogenicity of the bacterium. Objectives The aim of this study was to identify 5 types of fimA genotype strains in smokers and nonsmokers with periodontitis, before and after periodontal therapy. Material and Methods Thirty-one patients with periodontitis harboring P. gingivalis were selected: 16 nonsmokers (NS) and 15 smokers (SM). Clinical and microbiological parameters were evaluated at baseline and 3 months after periodontal treatment, namely: plaque index, bleeding on probe, probing depth, gingival recession and clinical attachment level. The frequency of P. gingivalis and fimA genotype strains were determined by polymerase chain reaction. Results Type I fimA was detected in the majority of SM and NS at baseline, and the frequency did not diminish after 3 months of treatment. The frequency of type II genotype was higher in SM than NS at baseline. After 3 months, statistical reduction was observed only for types II and V fimA genotypes in SM. The highest association was found between types I and II at baseline for NS (37.5%) and SM (53.3%). Conclusion The most prevalent P. gingivalis fimA genotypes detected in periodontal and smoker patients were genotypes I and II. However, the presence of fimA genotype II was higher in SM. Periodontal treatment was effective in controlling periodontal disease and reducing type II and V P. gingivalis fimA.

Abstract Objectives: Addition of chlorhexidine has enhanced the antimicrobial effect of glass ionomer cement (GIC) indicated to Atraumatic Restorative Treatment (ART); however, the impact of this mixture on the properties of these materials and on the longevity of restorations must be investigated. The aim of this study was to evaluate the effects of incorporating chlorhexidine (CHX) in the in vitro biological and chemical-mechanical properties of GIC and in vivo clinical/ microbiological follow-up of the ART with GIC containing or not CHX. Material and Methods: For in vitro studies, groups were divided into GIC, GIC with 1.25% CHX, and GIC with 2.5% CHX. Antimicrobial activity of GIC was analyzed using agar diffusion and anti-biofilm assays. Cytotoxic effects, compressive tensile strength, microhardness and fluoride (F) release were also evaluated. A randomized controlled trial was conducted on 36 children that received ART either with GIC or GIC with CHX. Saliva and biofilm were collected for mutans streptococci (MS) counts and the survival rate of restorations was checked after 7 days, 3 months and one year after ART. ANOVA/Tukey or Kruskal-Wallis/ Mann-Whitney tests were performed for in vitro tests and in vivo microbiological analysis. The Kaplan-Meier method and Log rank tests were applied to estimate survival percentages of restorations (p<0.05). Results: Incorporation of 1.25% and 2.5% CHX improved the antimicrobial/anti-biofilm activity of GIC, without affecting F release and mechanical characteristics, but 2.5% CHX was cytotoxic. Survival rate of restorations using GIC with 1.25% CHX was similar to GIC. A significant reduction of MS levels was observed for KM+CHX group in children saliva and biofilm 7 days after treatment. Conclusions: The incorporation of 1.25% CHX increased the in vitro antimicrobial activity, without changing chemical-mechanical properties of GIC and odontoblast-like cell viability. This combination improved the in vivo short-term microbiological effect without affecting clinical performance of ART restorations.