Caries inhibition in rats by a remineralizing toothpaste

We tested the anti-caries properties of a prototype remineralizing toothpaste containing sodium fluoride, soluble phosphate and soluble calcium, similar but not identical to Enamelon Toothpaste in specific pathogen-free Osborne-Mendel rats. A fluoride-free placebo and sodium fluoride-containing Crest Regular were used as negative and positive control toothpastes, respectively. Sixty weanling rats were randomly distributed into groups of 20, all were inoculated with S. mutans 10449S, ate diet 2000, and drank demineralized water. Each toothpaste, contained in coded tubes, was applied to the rats' teeth, once for one minute/day, five days/week. There was no difference in bacterial recoveries from tooth swabs among the groups at either the 22- or 37-day post-inoculation recovery date. After rat sacrifice and defleshing, heads were randomly coded and scored blindly for carious lesions according to Keyes/Larson methods. Only after scoring was completed were the random codes broken and the treatment groups identified. Both the Enamelon-like product and Crest Regular treatments resulted in lower total enamel caries scores than the placebo (p < 0.001). The sum of smooth surface scores was also lower for the fluoride-containing toothpastes than for the placebo (p < 0.001). However, the Enamelon-like product had greater caries inhibitory properties than Crest Regular on sulcal and approximal tooth surface categories (p = 0.004 and p = 0.045, respectively). Therefore, the Enamelon-like product had superior caries inhibiting properties compared to Crest Regular at these tooth areas.