Mutans streptococci remained viable on toothbrush bristles, in vivo, for 44 h.

BACKGROUND: Toothbrushes harbor a high number of cariogenic microorganisms. AIM: To investigate the viability of mutans streptococci (MS) on toothbrushes bristles and the production of extracellular polysaccharide (ECP) related to drying time. DESIGN: Twenty children were submitted to brushing without dentifrice. Toothbrushes were kept at room temperature from 0 to 48 h and then submitted to microbiological processing. The number of MS colonies/biofilms was expressed according to scores: 0=no colonies were detected; 1=1 to 50; 2=51 to 100; 3=over 100. The amount of ECP was evaluated according to scores: 0=absence; 1=ECP recovering until 50% of the surface; 2=ECP recovering more than 50% of the surface. Data were analyzed by Wilcoxon test (alpha=5%). RESULTS: At the periods of 0 to 16 h, the toothbrushes had intense bacterial contamination (score 3). From the 18-h, there was a statistically significant decrease in the MS viability (P=0.0078), with predominance of score 1 on periods of 20 to 44 h. The most detected ECP amount was at 0- and 12-h period (P<0.05) with reduction until 32-h period. CONCLUSIONS: Mutans streptococci remained viable on toothbrushes bristles, in vivo, for 44 h.