ABSTRACT
This work assessed the influence of the amount of dentifrice and fluoride (F) concentration in the product on the pH and inorganic components of Streptococcus mutans and Candida albicans dual-species biofilms. The biofilms were treated with suspensions of fluoride dentifrices containing 550 or 1100 ppm of F (550 F or 1100 F, respectively) administered at comparable intensities: (i-1) 550 F/0.08 g or 1100 F/0.04 g; (i-2) 550 F/0.16 g or 1100 F/0.08 g; and (i-3) 550 F/0.32 g or 1100 F/0.16 g. A placebo dentifrice (without NaF, 0.32 g) was used as a negative control. After the last treatment, the biofilm pH was measured and the F, calcium (Ca), and phosphorus (P) concentrations were determined. Data were subjected to an ANOVA/Kruskal-Wallis test, and a Student-Newman-Keuls test. The highest biofilm pH and F concentrations (biomass and fluid) were observed for 1100 F at i-3. Overall, 1100 F resulted in F levels similar to 550 F for i-1 and i-2. In addition, 550 F applied at i-2 and i-3 led to higher F in the biomass/fluid compared to 1100 F applied at i-1 and i-2, respectively. In biomass, the lowest Ca concentrations were observed for 1100 F at i-3. The conclusion drawn is that the treatment intensity holds greater significance as a parameter compared to the concentration of F or the amount of dentifrice when considered individually.
ABSTRACT
Despite the remarkable effects of sodium hexametaphosphate nanoparticles (HMPnano) on dental enamel de-/re-mineralization processes, information on the effects of these nanoparticles on biofilms is scarce. This study assessed the effects of HMPnano, with or without fluoride (F), on the inorganic components and pH of Streptococcus mutans and Candida albicans dual-species biofilms. Solutions containing conventional/micro-sized HMP (HMPmicro) or HMPnano were prepared at 0.5% and 1%, with or without 1100 ppm F. A 1100 ppm F solution and pure artificial saliva were tested as positive and negative controls, respectively. The biofilms were treated three times and had their pH analyzed, and the concentrations of F, calcium, phosphorus, and HMP in the biofilm biomass and fluid were determined. In another set of experiments, after the last treatment, the biofilms were exposed to a 20% sucrose solution, and the biofilm pH and inorganic components were evaluated. The 1% HMPnano solution with F led to the highest biofilm pH, even after exposure to sucrose. The 1% HMPnano solution without F led to significantly higher phosphorus concentrations in comparison to all other groups. It can be concluded that 1% HMPnano and F influenced the biofilm pH, besides affecting most of the inorganic components of the dual-species biofilms.
ABSTRACT
This study evaluated the effects of micrometric or nano-sized sodium hexametaphosphate (HMPnano), combined or not with fluoride (NaF, 1100 ppm), on dual-species biofilms of Streptococcus mutans and Candida albicans. Biofilms were treated with solutions containing the polyphosphates at 0.5% or 1.0%, with/without fluoride (F), in addition to positive and negative controls. Biofilms were analysed by colony-forming units (CFU) counting, metabolic activity, production of biomass, composition of extracellular matrix, and structure. 1% HMPnano + F led to the lowest S. mutans CFU, while C. albicans CFU counts were not affected by any solution. 1% HMPnano led to the lowest metabolic activity, except for 1% HMPnano + F. All solutions promoted reductions in biofilm biomass compared to controls. Also, 1% HMPnano + F promoted the lowest concentrations of carbohydrates in the biofilm matrix, besides substantially affecting biofilms' structure. In conclusion, HMPnano and F promoted higher antibiofilm effects compared with its micrometric counterpart for most of the parameters assessed.
