Antimicrobial Effect of Kids Dentifrices on Streptococcus mutans and Lactobacillus acidophilus: An In-Vitro Study

Background and purpose: Dental caries is one of the most common bacterial diseases in childhood. Using proper dentifrice is suggested to reduce the incidence of this disease. The aim of this study was to investigate the antimicrobial effects of different brands of children's dentifrice available in Iran’s market on Streptococcus mutans (PTCC1683) and Lactobacillus acidophilus (PTCC4356) strains. Materials and methods: After culturing standard bacterial strains, different kids dentifrice brands, including Irox, Bath, Misswake, Colgate, Oral-B, Bencer, and Frice were prepared by distilled water in 2 mg/ml and 4 mg/ml and added to pits in cultures medium. Then, the samples were incubated at 37°C for 24-48 hours and diameter of the antibacterial inhibitory haloarchaea was reported in millimeters. T-test was used for statistical analysis. Results: All dentifrices recorded an inhibitory haloarchaea diameter of 3-25 mm (except Bath and Irox at 2 mg/ml against S. mutans, 0 mm). The antibacterial strength of dentifrices was as follows: Oral-B> Colgate> Frice> Bencer> Misswake> Bath> Irox. At 4 mg/ml, the diameter of haloarchaea against L. acidophilus was approximately twice than that of S. mutans. The mean haloarchaea diameter was not significantly different between the control group and dentifrices at 4 mg/ml against S. mutans (P= 0.080). In other conditions, the mean diameter of haloarchaea in dentifrices was lower than that of the control group (P≤0.001). Conclusion: In this in-vitro study, Oral-B and Colgate (sodium fluoride 500 ppm) had the highest antibacterial effect and Bath and Irox (sodium monofluorophosphate 500 ppm) had the lowest antibacterial strength against the studied microorganisms. In addition, except for Bath and Irox, other dentifrices in various concentrations had desirable antibacterial properties.