Effects of curcumin-mediated antimicrobial photodynamic therapy associated to different chelators against Enterococcus faecalis biofilms.

BACKGROUND: The aim of this study was to evaluate curcumin-mediated antimicrobial photodynamic therapy (aPDT) action combined or not with ethylenediaminetetraacetic acid (EDTA) and hydroxyethylidene bisphosphonate (HEBP) on Enterococcus faecalis biofilms. METHODS: Enterococcus faecalis biofilms were grown on dentin bovine discs in brain heart infusion (BHI) medium with 1% glucose, in aerobic conditions at 37°C for 7 days. Then, they were randomly distributed to one of experimental conditions, as follows: control, 75 J.cm-2 LED, 600 µmol.L-1 curcumin, 17% EDTA, 18% HEBP, 600 µmol.L-1 curcumin plus 75 J.cm-2 LED, 600 µmol.L-1 curcumin plus 17% EDTA, 600 µmol.L-1 curcumin plus 18% HEBP, 600 µmol.L-1 curcumin plus 17% EDTA and 75 J.cm-2 LED or 600 µmol.L-1 curcumin plus 18% HEBP and 75 J.cm-2 LED. The viability of microorganisms and the vitality of biofilms were determined by colony forming unit counts and confocal scanning laser microscopy (CSLM), respectively. Statistical analysis was conducted by Kruskal Wallis and Dunn's post-hoc tests (α = 0.05). RESULTS: The results showed that all combinations of aPDT with chelators significantly reduced the viability of microbial cells and the vitality of biofilms in comparison to control, even when considering deeper layers of biofilms. CONCLUSION: The combination of curcumin with EDTA and HEBP similarly improved the effect of aPDT on E. faecalis biofilms.

Cytotoxic effect and apoptosis pathways activated by methylene blue-mediated photodynamic therapy in fibroblasts.

Antimicrobial photodynamic therapy (aPDT) has been used as an adjuvant treatment of oral infections as a minimal intervention clinical approach. Its antimicrobial efficacy was demonstrated in several studies; however, there is a lack of evidence on its cytotoxic effect on mouse fibroblasts (NIH/3T3). The aim of this study was to evaluate the cytotoxicity and apoptotic pathways of methylene blue-mediated aPDT on mouse fibroblasts. Cells were treated with 0.1 or 1.0 mg.L-1 methylene blue (MB), and 0.075 or 7.5 J.cm-² LED at 630 nm. Cell viability was examined by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) and crystal violet (CV) assays, while cDNA expression for Bax, Bad, Bcl-2, VDAC-1, cytochrome C and Fas-L was assessed by qRT-PCR (1, 3, 6 and 24 h). The differences between groups were detected by Kruskal-Wallis and post-hoc Dunn's tests for MTT and CV assays, and by ANOVA and post-hoc Tukey test for qPCR (P < 0.05). The combination of 1.0 mg.L-1 MB and 7.5 J.cm-² LED significantly reduced the cellular viability, whereas MB and LED alone were innocuous to fibroblasts. MB-mediated aPDT increased the expression of cytochrome C and Fas-L after 3 h, and Bax/Bcl-2, Bad/Bcl-2, and VDAC-1 after 6 h from treatment. Based on these results, MB-mediated aPDT induced cytotoxicity on mouse fibroblasts, with consequent activation of Bcl-2 apoptosis signaling pathways. Further studies are needed to determine the adequate parameters of aPDT to inactivate microorganisms without damaging fibroblasts.

The effectiveness of curcumin-mediated antimicrobial photodynamic therapy depends on pre-irradiation and biofilm growth times.

BACKGROUND: The aim of this study was to determine the influence of distinct pre-irradiation times (PIT) of curcumin on the effectiveness of antimicrobial photodynamic therapy (aPDT) against intact dentin caries biofilms grown for 3 or 5 days. METHODS: The microcosm biofilms grew on non-fluorescent glass blocks immersed in McBain medium with 1% sucrose, using microaerophilic conditions at 37 °C for 3 or 5 days. The biofilms were treated by the association of 600 µmol.L-1 curcumin using different pre-irradiation times (1, 2 or 5 min) combined with 0 or 75 J.cm-2 blue LED. Then, the vitality of biofilms was determined by confocal scanning laser microscopy (CSLM), after being stained with the mixture of ethidium bromide and fluorescein diacetate. Statistical analysis was performed by two-way ANOVA and post-hoc Tukey tests, after arcsine transformation (P < 0,05). RESULTS: In comparison to control, curcumin alone (PIT = 5 min) and all combinations of curcumin and LED reduced significantly the vitality of 3-day biofilms. Distinctly, only curcumin plus LED using PITs of 2 or 5 min were effective in reducing the vitality of 5-day biofilms. CONCLUSION: Curcumin-mediated aPDT significantly decreased the vitality of intact dentin caries microcosms grown during 3 or 5 days, although successful treatments of 5-day biofilms required longer PITs in comparison to their counterparts.

Curcumin-mediated antimicrobial photodynamic therapy reduces the viability and vitality of infected dentin caries microcosms.

BACKGROUND: To our knowledge, there is a lack of evidence on the effect of Antimicrobial Photodynamic Therapy (aPDT) by the application of curcumin against complex biofilms of dental caries lesions. This study aimed to evaluate the viability, vitality, and acid metabolism of infected dentin caries microcosms treated with curcumin-mediated aPDT. METHODS: After microcosm biofilms growing anaerobically on bovine dentin disks immersed in McBain medium with 1% sucrose at 37 °C for 5 days, the biofilms were treated by the association of DMSO water solution or 600 µmol L-1 curcumin with 0, 37.5 or 75 J cm-2 blue LED (455 nm). Then, the colony-forming units (CFU) counts of total microorganisms, total streptococci, mutans streptococci, and total lactobacilli were determined by plating. The lactic acid concentration was analyzed by enzymatic spectrophotometry method, while the vitality of intact biofilms was evaluated by confocal laser scanning microscope (CLSM). Statistical analysis was performed by Kruskal Wallis and post-hoc Dunn's tests (P < 0.05). RESULTS: Curcumin alone did not affect the viability of microorganisms and the vitality of intact biofilms. However, 75 J cm-2 LED alone decreased the total microorganisms and total lactobacilli counts. The combination of curcumin and LED reduced significantly the counts of all microorganism groups and the vitality of intact biofilms. Differences were not observed between the lactic acid concentrations of distinct groups. CONCLUSIONS: Therefore, curcumin-mediated aPDT was effective in reducing the viability and the vitality of infected dentin caries microcosms, without interfering in their acidogenicity.

The Brazilian validation of a health literacy instrument: the newest vital sign.

OBJECTIVE: This study aimed to perform the cross-cultural adaptation and validation of the NVS for Brazilian Portuguese. MATERIAL AND METHODS: Two hundred and fifty adults responded to the adapted version of the NVS, the Brazilian version of the Rapid Estimate of Adult Literacy in Dentistry (BREALD-30), ten questions of the National Functional Literacy Index (NFLI), and a questionnaire about demographic and oral health-related aspects. Statistical analysis determined the internal consistency, stability, difficulty of items, and convergent/discriminant/predictive validities of the NVS. p < .05 was considered significant. RESULTS: The NVS displayed a good internal consistency (Cronbach's alpha = 0.79) and a fair stability (ICC = 0.57; 0.39-0.70 95% CI). Seventy-two percent of participants answered the easier question (#5) correctly, whereas only 28.4% were successful in responding the most difficult question (#1). The convergent validity of the NVS was demonstrated by its significant correlation with the BREALD-30 (Rs = 0.601, p < .001) and NFLI (Rs = 0.544, p < .001). The observation of higher NVS scores among health professionals, white and more educated people confirmed the discriminant validity of the instrument. Moreover, health literacy was a significant predictor of self-reported oral health and reason for dental utilization. CONCLUSION: The NVS demonstrated adequate psychometric properties to be applied in Brazilian oral health epidemiological surveys.

The in vitro effect of Antimicrobial Photodynamic Therapy on dental microcosm biofilms from partially erupted permanent molars: A pilot study.

BACKGROUND: Antimicrobial Photodynamic Therapy (aPDT) could enhance the prevention of dental caries lesions in pits and fissures of partially erupted molars, by killing microorganisms from complex dental biofilms. This pilot study aimed to evaluate the effect of Antimicrobial Photodynamic Therapy (aPDT) on the viability of specific microorganism groups of dental microcosm biofilms from occlusal surfaces of first permanent molars in eruption. METHODS: Dental microcosm biofilms grown on bovine enamel blocks, from dental plaque collected on occlusal surfaces of a partially erupted lower right first permanent molar, with McBain medium plus 1% sucrose in anaerobic condition at 37 °C for 72 h. The experiments were performed in eight groups: L-P- = no treatment (control), L18.75P- = 18.75 J/cm2 LED, L37.5P- = 37.5 J/cm2 LED, L75P- = 75 J/cm2 LED, L-P+ = 200 mM TBO, L18.75P+ = 200 mM TBO + 18.75 J/cm2 LED, L37.5P+ = 200 mM TBO + 37.5 J/cm2 LED, and L75P+ = 200 mM TBO + 75 J/cm2 LED. The counts of total microorganisms, total streptococci and mutans streptococci were determined on selective media agar plates by colony-forming units per mL. The log-transformed counts were analyzed by Kruskal-Wallis and post-hoc Dunn's test (P < 0.05). RESULTS: The counts of all microorganisms treated in the group L75P+ were statistically lower than those treated in L-P-. The aPDT promoted a significant reduction of microorganisms, with a trend of dose-dependent effect. CONCLUSION: TBO-mediated aPDT was effective in reducing the viability of specific microbial groups in dental microcosm biofilms originated from occlusal of permanent molars in eruption.