Buffering Capacity and Effects of Sodium Hexametaphosphate Nanoparticles and Fluoride on the Inorganic Components of Cariogenic-Related Biofilms In Vitro

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.

Activity of Sodium Trimetaphosphate Nanoparticles on Cariogenic-Related Biofilms In Vitro

“…Interestingly, the reduction in the TMP particle size led to an additive effect on the pH of the biofilms as even after sucrose exposure, the biofilms treated with 1TMPn and 3TMPn, combined with F, had significantly higher pH than those treated with their microparticulate counterparts and the positive control (1100 ppm F). In fact, such data are in line with those in literature for another phosphate, which demonstrated that the reduction of sodium hexametaphosphate particle size enhanced its buffering capacity [ 29 ]. Such a trend can also be justified by the higher reactivity of nanoparticles over the microparticles, leading to the enhancement of the effects observed for the groups treated with the conventional particles [ 22 , 23 ].…”