The Activity of Calcium Glycerophosphate and Fluoride against Cariogenic Biofilms of Streptococcus mutans and Candida albicans Formed In Vitro.

This study evaluated the effects of calcium glycerophosphate (CaGP), with or without fluoride (F), on dual-species biofilms of Streptococcus mutans and Candida albicans. The biofilms were treated three times with 0.125, 0.25, and 0.5% CaGP solutions, with or without 500 ppm F (NaF). Additionally, 500 and 1100 ppm F-solutions and artificial saliva served as controls. After the final treatment, the microbial viability and biofilm structure, metabolic activity, total biomass production, and the composition of the extracellular matrix composition were analyzed. Regardless of the presence of F, 0.25 and 0.5% CaGP promoted a higher biomass production and metabolic activity increase than the controls (p < 0.05). F-free CaGP solutions reduced bacterial cell population significantly more than the 500 ppm F group or the negative control (p < 0.05). All the groups reduced the proteins, and 0.5% CaGP combined with F led to the highest reduction in the carbohydrate and nucleic acids content of the extracellular matrix (p < 0.05). It can be concluded that CaGP alone affected the number of bacterial cells and, when combined with F, reduced its production of biomass, metabolic activity, and the expression of the extracellular matrix components.

Effects of Sodium Hexametaphosphate and Fluoride on the pH and Inorganic Components of Streptococcus mutans and Candida albicans Biofilm after Sucrose Exposure

In order to improve the anticaries effects of fluoridated products, the supplementation of these products has been considered a promising alternative for caries control. This study evaluated the effects of sodium hexametaphosphate (HMP) and/or fluoride (F) on the inorganic components and pH of Streptococcus mutans and Candida albicans dual-species biofilms. The biofilms were treated 72, 78, and 96 h after the beginning of their formation with 0.25, 0.5, or 1% HMP-containing solutions with or without F (500 ppm, as sodium fluoride). F-containing solutions (500 ppm and 1100 ppm) and artificial saliva were used as controls. The biofilms were exposed to a 20% sucrose solution after the third treatment. Along with the biofilm pH, the concentrations of F, calcium, phosphorus (P), and HMP were determined. HMP, combined with F, increased F levels and decreased P levels in the biofilm fluid compared to that of the solution with 500 ppm F. Exposure to sucrose decreased the concentrations of all ions in the biomass, except for HMP; 1% HMP, combined with F, promoted the highest pH. It can be concluded that HMP affected the inorganic composition of the biofilm and exerted a buffering effect on the biofilm pH.

Effect of sodium hexametaphosphate and fluoride on dual-species biofilms of Candida albicans and Streptococcus mutans.

This study evaluated the effect of sodium hexametaphosphate (HMP), administered alone or in combination with fluoride (F), on dual-species biofilms of Streptococcus mutans and Candida albicans. Biofilms were treated with HMP solutions at 0.25%, 0.5% and 1%, alone or combined with F (0.05%), and compared by evaluating their structure and quantifying the colony-forming units (CFUs), metabolic activity, production of biomass and extracellular matrix components. All HMP-containing solutions were capable of reducing metabolic activity, the biofilm biomass, and the extracellular matrix components. Furthermore, the treatment with 1% HMP/F significantly reduced the CFUs of S. mutans, although it showed no effect on the CFUs of C. albicans, in the dual-species biofilms. In general, the combination of HMP and F influenced all the parameters analyzed from dual-species biofilms, except the CFUs of C. albicans.

Calcium glycerophosphate and fluoride affect the pH and inorganic composition of dual-species biofilms of Streptococcus mutans and Candida albicans.

OBJECTIVES: This study evaluated the influence of calcium glycerophosphate (CaGP), combined with or without fluoride (F), on the pH and concentrations of F, Ca, and P of dual-species biofilms of Streptococcus mutans and Candida albicans, with or without exposure to sucrose. METHODS: The biofilms (n = 9) received three treatments (72, 78, and 96 h after the start of their formation) at three CaGP concentrations (0.125, 0.25, or 0.5%), with or without F at 500 ppm (as NaF). Solutions containing 500 and 1100 ppm F and artificial saliva were also tested as controls. Biofilm pH was measured, and the concentrations of F, Ca, P, and CaGP were determined (solid and fluid phases). In a parallel experiment, after the third treatment, the treated biofilms were exposed to a sucrose solution, and the pH of the medium, F, Ca, P, and CaGP was determined. Data were subjected to two-way ANOVA, followed by Fisher's LSD test (p < 0.05). RESULTS: Treatment with CaGP and 500 ppm F led to the highest pH values and F and Ca concentrations in the biofilm biomass, both with and without sucrose exposure. CaGP without F led to higher Ca and P concentrations in the biofilm fluid. CONCLUSIONS: CaGP increased F, Ca, and P concentrations in the biofilm, and its presence promoted an increase in the pH of the medium, even after exposure to sucrose. CLINICAL SIGNIFICANCE: The present results elucidate the mechanism by which CaGP and F act on biofilms, further interfering with dental caries dynamics.

Effects of Sodium Trimetaphosphate, Associated or Not with Fluoride, on the Composition and pH of Mixed Biofilms, before and after Exposure to Sucrose.

The aim of the present study was to evaluate the influence of sodium trimetaphosphate (TMP), associated or not with fluoride (F), on the concentrations of F, calcium (Ca), and phosphorus (P) and on the pH of mixed biofilms of Streptococcus mutans and Candida albicans, before and after exposure to sucrose. The biofilms received three treatments (72, 78, and 96 h after the beginning of their formation), at three TMP concentrations (0.25, 0.5, or 1%), with or without F at 500 ppm. Solutions containing 500 and 1,100 ppm F as well as artificial saliva were also tested as controls. Biofilm pH was measured and the concentrations of F, Ca, and P were determined (solid and fluid phases). In a parallel experiment, after the third treatment (96 h), the biofilms were exposed to a 20% sucrose solution to simulate a cariogenic challenge and the pH of the medium, F, Ca, P, and TMP were determined. The data were submitted by two-way ANOVA, followed by Fisher's least significant difference test (p < 0.05). Treatment with TMP and 500 ppm F led to higher F concentration in the biofilm fluid. Although TMP did not affect Ca concentrations, biofilms treated with TMP alone presented higher P concentrations. Treatment with 1% TMP and F led to the highest pH values of the biofilm, both before and after the cariogenic challenge. It was concluded that TMP increases F and P in the biofilm and that its presence promotes an increase in the pH of the medium, even after the cariogenic challenge.

Activity of sodium trimetaphosphate, associated or not with fluoride, on dual-species biofilms.

This study aimed to evaluate the effect of sodium trimetaphosphate (TMP), either with fluoride (F) or without fluoride, on dual-species biofilms of Streptococcus mutans and Candida albicans. The 72 h biofilms were treated with 0.25%, 0.5%, or 1% TMP solutions, combined or not with 500 ppm F, and analysed by quantification of viable plate counts, metabolic activity, biomass, and extracellular matrix components. Biofilm structure was evaluated by scanning electron microscopy (SEM). TMP significantly reduced the number of S. mutans cells and biomass only when associated to F. Furthermore, fluoride-free TMP promoted significant reductions in biofilm metabolism, while all the tested solutions decreased the contents of the biofilm matrix compared to untreated groups. Regarding biofilm structure, TMP associated with F led to the formation of a less compact biofilm. It was concluded that TMP alone had a reducing effect, mainly on the metabolism and the extracellular matrix components of the biofilms.

Antimicrobial photodynamic therapy improves the alveolar repair process and prevents the occurrence of osteonecrosis of the jaws after tooth extraction in senile rats treated with zoledronate.

This study evaluated the effects of antimicrobial photodynamic therapy (aPDT) in the alveolar repair of rats with major risk factors for bisphosphonate-related osteonecrosis of the jaws (BRONJ). Senile rats received 0.45 ml of vehicle (VEH and VEH/aPDT) or 0.45 ml of zoledronate (ZOL and ZOL/aPDT) every three days for seven weeks. After three weeks of treatment, the first lower left molar was extracted. VEH/aPDT and ZOL/aPDT were submitted to aPDT on the extraction site at 0, 2 and 4 days postoperatively. Euthanasia was performed 28 days postoperatively and the extraction site was evaluated by clinical, histological, histometric, histochemical and immunohistochemical analysis. ZOL showed tissue repair impairment; lower percentage of newly formed bone tissue (NFBT); higher percentage of non-vital bone tissue (NVBT); fewer mature collagen fibers and increased immunolabeling for tumor necrosis factor (TNFα), interleukin (IL)-1ß and IL-6. ZOL/aPDT showed clinical and histological characteristics of the extraction site, percentage of NFBT and percentage of mature collagen fiber similar to VEH. Percentage of NVBT and immunolabeling for inflammatory cytokines in ZOL/aPDT was lower than in ZOL. Immunolabeling for tartarato-resistant acid phosphatase (TRAP) was lower in ZOL and ZOL/aPDT. aPDT in the dental extraction site improves tissue repair process and prevents the occurrence of BRONJ-like lesions after tooth extraction.

pH changes of mixed biofilms of Streptococcus mutans and Candida albicans after exposure to sucrose solutions in vitro.

OBJECTIVE: This study aimed to standardize an in vitro experimental model able to reproduce the pH changes that occur in dental biofilm under in vivo conditions, using a mixed biofilm of Streptococcus mutans and Candida albicans. DESIGN: Biofilms were developed for 96 h, and exposed to three different concentrations of sucrose (10, 20 or 30%) during 1, 3 or 5 min. The pH was measured before exposure to sucrose, immediately after its removal from the biofilms, and at 1, 3, 5 and 10 min after removal. RESULTS: Sucrose solutions at 10 and 20% required 1 min to significantly reduce the biofilm pH, while for 30% sucrose a significant reduction was already seen immediately after its removal, even for the shortest exposure time. For an exposure of 3 min to 20% sucrose, the biofilm pH attained the critical value for hydroxyapatite dissolution when measured 1 min after sucrose removal, followed by a recovery phase. CONCLUSIONS: A mixed biofilm of S. mutans and C. albicans exposed to a 20% sucrose solution for 3 min exhibited a pattern of pH change similar to that observed in vivo, despite at a higher speed when compared to in vivo conditions.

Interactions between Candida albicans and Candida glabrata in biofilms: Influence of the strain type, culture medium and glucose supplementation.

The relationship among Candida species may be influenced by several factors. Thus, this study evaluated the interactions between Candida albicans and Candida glabrata in biofilms, varying the strain type, culture medium and glucose supplementation. Biofilms were formed for 48 hours in Sabouraud dextrose broth (SDB) or RPMI 1640, supplemented with 0%, 1% or 5% glucose. Each strain of C. albicans was combined with two strains of C. glabrata, generating four biofilm associations, which were quantified by colony-forming units (CFUs), total biomass and metabolic activity. Data were analysed by ANOVA and Tukey's HSD test (α = 0.05). For CFUs, all associations were classified as indifferent for biofilms formed in RPMI 1640, while for SDB the interactions were antagonistic for C. albicans and indifferent for C. glabrata. The association of reference strains resulted in a dual-species biofilm with biomass significantly higher than that observed for each single biofilm developed in SDB. The metabolic activity of dual-species biofilms did not significantly differ from that found for single ones, except for co-culture of the reference strains. Glucose supplementation and culture media had a significant influence on all parameters. In conclusion, the strain type, culture medium and glucose supplementation influenced the interactions between C. albicans and C. glabrata.

Efeito do trimetafosfato de sódio, associado ou não ao fluoreto, na biomassa e fluido do biofilme misto contendo Streptococcus mutans e Candida albicans / Effect of sodium trimetaphosphate, associated or not to fluoride, on biomass and fluid of mixed biofilm containing Streptococcus mutans e Candida albicans

O presente estudo teve por objetivo verificar o efeito do trimetafosfato de sódio (TMP), associado ou não ao fluoreto (F), sobre células cultiváveis, biomassa total, atividade metabólica e composição da matriz extracelular de biofilmes mistos de S. mutans e C. albicans, bem como sobre as concentrações de F, cálcio (Ca) e fósforo (P) (biofilme total e fluido do biofilme) e no pH destes biofilmes formados in vitro. Para ambos os estudos, os biofilmes foram formados em poços de placas de microtitulação, colocando uma suspenção (1x107 células/mL C. albicans + 1x108 células/mL S. mutans) em saliva artificial suplementada com sacarose (0,4%), a qual tinha metade de seu conteúdo renovada a cada 24 horas. Os biofilmes foram tratados três vezes (72, 78 e 96 horas de formação), por um minuto, com soluções contendo TMP (0,25, 0,5 ou 1%) com ou sem 500 ppm F, além de soluções contendo 500 e 1100 ppm F, adotadas como controles positivos. A saliva artificial foi utilizada como tratamento e considerada como controle negativo. Para o estudo mircrobiológico, após o terceiro tratamento foram realizados os testes de quantificação de células cultiváveis (CFU), biomassa total (teste colorimétrico de cristal violeta ­ CV), atividade metabólica (redução de XTT) e quantificação dos componentes da matriz extracelular (proteína, carboidrato e DNA). Todos os ensaios foram realizados em triplicata, em três ocasiões diferentes. Os resultados foram submetidos à análise de variância a um critério, seguida pelo teste Fisher LSD (p<0,05). O TMP apresentou efeito redutor principalmente no metabolismo e nos0020 componentes da matriz extracelular do biofilme. Para o estudo da concentração de F, Ca, e P, após o período de tratamento, estes foram analisados no biofilme total e no fluido do biofilme após a mensuração do pH do biofilme. Em outro conjunto de experimentos, após o terceiro tratamento (96 h de formação de biofilme) o biofilme foi exposto, por 3 minutos, à solução de sacarose a 20%. Esta foi removida e, após 1 minuto, analisou-se o pH do meio e as concentrações de F, Ca, e P tanto na biomassa como no fluido do biofilme. Os dados foram submetidos a análise de variância a dois critérios, seguida pelo teste de Fisher LSD (p<0,05). O tratamento com TMP aumentou a concentração de F e P no fluido do biofilme, além de manter o pH do meio mais próximo do neutro, mesmo após a exposição do biofilme à sacarose. Assim, é possível concluir que o TMP interfere no metabolismo, composição orgânica e inorgânica, bem como no pH do biofilme testado(AU)

The aim of the present study was to verify the effect of sodium trimetaphosphate (TMP), associated or not to fluoride (F), on cultivable cells, total biomass, metabolic activity and composition of the extracellular matrix of mixed biofilms of S. mutans and C. albicans, as well as on the concentrations of F, calcium (Ca) and phosphorus (P) (total biofilm and biofilm fluid) and pH of these biofilms formed in vitro. For both studies, the biofilms were formed in wells of microtiter plates by placing a suspension (1 x 107 cells/mL C. albicans + 1x108 cells/mL S. mutans) in artificial saliva supplemented with sucrose (0,4%), which had half of its content renewed every 24 hours. Biofilms were treated three times (72, 78 and 96 hours of formation), for one minute, with solutions containing TMP (0.25, 0.5 or 1%) with or without 500 ppm F, as well as solutions containing 500 and 1100 ppm F, adopted as positive controls. Artificial saliva was used as treatment and considered as the negative control. For the microbiological study, the following tests were performed: quantification of cultivable cells (CFU), total biomass (colorimetric crystal violet test - CV), metabolic activity (XTT reduction) and quantification of matrix components (protein, carbohydrate and DNA). All assays were performed in triplicate on three different occasions. The results were submitted to one-way analysis of variance, followed by the Fisher LSD?s test (p<0.05). TMP showed a reducing effect mainly on the metabolism and components of the extracellular matrix of the biofilm. For the study of the concentrations of F, Ca, and P, these ions were analyzed in the total biofilm and in the biofilm fluid after treatment with the test solutions and after the pH measurement of the biofilm. In another set of experiments, after the third treatment (96 h of biofilm formation), the biofilms were exposed for 3 minutes to a 20% sucrose solution. This was removed and after 1 minute the biofilms were collected, and the pH of the medium and F, Ca, and P concentrations were determined both in the biomass and in the biofilm fluid. The data were submitted by two-way analysis of variance, followed by Fisher LSD's test (p<0.05). Treatment with TMP increased F and P concentration of the biofilm fluid, and maintained the pH of the medium close to neutral values even after exposure of the biofilm to sucrose. Thus, it is possible to conclude that TMP interferes with the metabolism, organic and inorganic composition and the pH of the biofilm tested(AU)