The Effect of a Low Fluoride Delivery System on Bacterial Metabolism, Bacterial Attachment and Caries

摘要

The first goal of the low fluoride delivery system contract was to establish whether the agents to be tested were effective as a result of either inhibiting bacterial growth or killing the bacteria which were found in the oral cavity. These in vitro studies established that SnF2 inhibited bacterial growth at 60 ppm F and killed bacteria at 125 ppm F. The other fluoride agents had these antimicrobial properties at higher concentrations. Hence, at the therapeutic release goal of 1-2 ppm, the effect of fluorides would not be due to killing of the organisms. The next phase of the study was to establish the lowest level of various fluoride solutions which had an effect on the bacterial acid production of Streptococcus mutans, a known cariogenic organism which produces caries by its release of acid. This study also established that the low levels of fluoride proportionately had a greater effect on acid production. Electron dense bodies, identified as tin by electron microprobe, found in bacterial cells exposed to 5 ppm fluroride as SnF2, gives strong indirect evidence that fluorides, even in trace amounts, become concentrated in the bacterial cells. Furthermore, the bacterial cells exposed to 5 ppm SnF2 showed other ultrastructural changes within the cell compatible with altered growth of these cells.