Binary systems and their nuclear explosions

Peer ReviewedPreprin

In vitro antibacterial effect of carbamide peroxide on oral biofilm

This study compared the effects of carbamide peroxide (CP) and chlorhexidine (CHX) on oral biofilm in vitro. Collagen-coated hydroxyapatite discs were inoculated with subgingival plaque. After 3 weeks, the emergent biofilms were subjected to 1-, 3-, and 10-min exposures of a 1% CHX gel, a 5% CP gel and rinse, and a 10% CP gel and rinse. Subsequently, the biofilms were stained using a two-colour fluorescent dye kit for confocal laser scanning microscopy, and the volume ratio of dead bacteria to all bacteria was analysed. Compared to a non-treated gel control, the active agents killed bacteria on all the discs, with higher concentration and longer exposure times killing more bacteria. The rinse form disrupted the biofilm quicker than the gel form. Overall, 10% CP showed more disruption of biofilm and a greater proportion of killed bacteria than 1% CHX (p<0.05)

Assessment of the cariogenic potential of Streptococcus mutans strains and its relationship to in vivo caries experience

Strains of Streptococcus mutans isolated from the plaque of 6 subjects were studied using an in vitro model to determine whether differences in their cariogenic potential could be detected, and if so, whether the results correlated with the caries experience of the individuals. Each strain was incubated with a bovine enamel slab and 5% (w/v) sucrose for 24‐h periods. The acidogenic potential was assessed by pH measurement and analysis of acid anion production. Microradio‐graphic and microdensitometric assessment of the enamel, together with measurement of the change in calcium concentration of the reaction mixture were used to determine the demineralizing potential of each strain. Significant differences in cariogenic potential were found between some of the strains tested, and correlations were found between 3 of the test parameters and the decayed‐missing‐filled‐surface score of the individuals. The results suggest that the caries experience of individuals may be related, to some extent, to the cariogenic potential of their S. mutans strains