Amount and Distribution of Extracellular Polysaccharides in Dental Microbial Plaque

Abstract

Extracellular polysaccharides (EPS) in human dental plaque were investigated in relation to fluoride concentration in drinking water under both natural and experimental conditions. In a low-fluoride area (0.2 ppm F^––) the level of EPS amounted to 15.2% and in a fluoridated area (1.0 ppm F^––) to 10.3% of the dry weight of samples (a significant difference). Under experimental conditions (after mouth-rinsing with fluoride-sucrose solutions), a significant influence of F^–– on the level of EPS could only be observed at a concentration of 10.0 ppm. The ratio of water-soluble and alkali-soluble fractions was approximately 60:40 in both natural and experimental plaques.

Predominant Plaque Flora of Tanzanian Children Exposed to High and Low Water Fluoride Concentrations

“…This is in agreement with the conclusions which can be made on the basis of previous human and animal studies [Jordan et al, 1969;De Stoppelaar et al, 1969;Myers and Handelman, 1971;Englander and Keyes, 1966]. Broukal and Zajicek [1974] have dem onstrated that total extracellular polysac charide is reduced by approximately one third in plaque from subjects exposed to 1 ppm relative to no fluoride in the drinking water. The fact that rinsing with sucrose so lutions containing fluoride had a similar ef fect only at a fluoride concentration of 10 ppm might have indicated that a long term effect, i.e.…”

“…However, the re sults of the present study do not seem to support this explanation (table V). Since Carlsson and co-workers [Carlsson et al, 1969;Carlsson, 1960] have shown that both glucosyltransferase and levansucrase are highly insensitive to fluoride, the most reasonable explanation to the findings of Broukal and Zajicek [1974] appears to be an enhanced degradation of EPS under the influence of fluoride as recently suggested by Schachtele [1977].…”

Distribution and Forms of F in Saliva and Plaque

“…Enzymes responsible for synthesis of ex tracellular glucan and fructan from sucrose are insensitive to F [Carlsson et ai, 1969;Carlsson, 1970], although Bowen and Hew itt [1974] observed reduction in growth and increase in fructose-glucose ratios in extra cellular polysaccharides produced by strains of S. mutans when grown on media contain ing 70 ppm F. No statistically significant ef fect of water-borne F was found on percen tages of S. mutans and S. sanguis in the studies of de Stoppelaar et al [1969], How ever, total extracellular polysaccharide was stated in one report to be reduced by ap proximately one third in plaque from a fluo ridated area [Broukal and Zajicek, 1974] although rinsing with sucrose solution con taining 0.2, 1.0 and 10 ppm F reduced the extracellular polysaccharide only at the highest concentration. Loesche et al [1973] found that following topical application with an acidulated phosphate fluoride gel, the percentage of S. mutans, but not S. san guis, in plaques of 15 out of 17 children aged 15-16 years was reduced for at least 12 weeks.…”

In vivo Plaque Formation on Enamel Surfaces Treated with Topical Fluoride Agents

“…There are several ways of explaining this behavior. Firstly it is possi ble that the high levels of F (100 ppm) re leased from the soluble, dissolving and disintegrating CaF^ layers may interfere with the bacterial metabolism of organ isms already adsorbed to the CaFj layer, reducing the production of glucans and thus reducing plaque accumulation rates \Grdn et al, 1969;Broukal and Zajicek, 1974]. Bowen and Hewitt [1974] have shown that the glucan/fructan ratio is re duced significantly in the extracellular polysaccharides produced by Streptococ cus mutans organisms in the presence of 70 ppm fluoride.…”