Effects of bicarbonate-based dental powder, fluoride, and saccharin on dental caries and on Streptococcus sobrinus recoveries in rats.

The effects of NaHCO3-based dental powder containing NaF and sodium saccharin on dental caries and Streptococcus sobrinus recoveries in rats were studied. Weanling specific-pathogen-free Osborne-Mendel (SPFOM) rats were inoculated with S. sobrinus 6715-13WT. One of six infected groups was topically treated with either demineralized water (DW), a dental powder suspended such that there was 1 part solid per 2 parts DW, 0.073% NaF, 0.5% Na-saccharin (Nas), or a combination of NaF and Nas at the same concentrations. NaF-supplemented DW (at 10 ppm F-) was provided to the 6th group of infected rats as a positive treatment control, but this group was otherwise untreated. A seventh but uninfected group was topically treated with DW. All topical treatments were given once for one min daily per rat, for five days per week. Animals' teeth were swabbed for recovery of 6715-13WT and total recoverable flora. At 37 days after start of treatment, S. sobrinus recoveries were lower only for those rats topically treated with the dental powder (p less than 0.05) by comparison with recoveries from the infected, topical DW-treated group. Caries scores, however, were 42% lower for the groups receiving the dental powder (p less than 0.005), 30% lower for those treated with the combined NaF-Nas (p less than 0.005), and 47% lower for the NaF-supplemented drinking water group (p less than 0.005). The dental powder effects, like those for the combined NaF-Nas and NaF drinking water, were evident on both smooth and fissure tooth surfaces. Both the 10 ppm F- drinking water and the dental powder significantly (p less than 0.005) reduced fissure caries scores below the level elicited by the indigenous mutans-free flora in the DW-treated uninfected rats; however, these reduction were not significantly different from one another. Thus, the 10 ppm F- drinking water and the dental powder equally inhibited not only the S. sobrinus-attributable component of caries but probably also the component of caries attributable to the indigenous oral flora.