Bicarbonate-based powder and paste dentifrice effects on caries

The effects of sodium bicarbonate-based powder and paste dentifrices on dental caries and Streptococcus sobrinus recoveries in rats were studied. Three S. sobrinus 6715-13WT infected groups of specific pathogen-free weanling rats, consuming a diet which contains 56% sucrose, were topically treated with either demineralized water, dentifrice paste, or dentifrice powder. Both the paste and powder contained 0.22% (w/w) NaF. All topical treatments were given for one min daily per rat, five days a week. Animals' teeth were swabbed for recovery of 6715-13WT and total recoverable flora. Recoveries of 6715-13WT were 75% lower from both powder-treated and paste-treated dentifrice than from water-treated rats' teeth (p less than 0.001). Total caries scores were 45% lower for the powder-treated and 43% lower for the paste-treated rats than the water-treated ones (p less than 0.01). The major portion of the caries inhibition was evident on smooth tooth surfaces, 68% for powder-treated and 65% for paste-treated by comparison with water-treated animals (p less than 0.01), although a lesser caries reduction was also evident in tooth fissures (sulci). Thus, both powder and paste formulations of a sodium bicarbonate-based dentifrice containing 0.22% NaF equally and potently inhibited caries in rats, challenged bacteriologically and dietarily to develop severe caries.