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Changes in Lactate and Other Ions in Plaque and Saliva After a Fluoride Rinse and Subsequent Sucrose Administration



Gerald L. Vogel, Z Zhang, Laurence C. Chow, A L. Galvin


The relative importance of the various proposed mechanistic effects of fluoride on the changes in oral ion concentrations associated with caries progression and remission are not fully elucidated. This is partially due to the fact that attempts to examine these concentrations is confounded by factors such as the potential synergistic or antagonistic interactions between these mechanisms and the delivery and clearance of both the fluoride rinse and the cariogenic substrate. Recently two studies have separately addressed some of these factors. The purpose of this study was to examine the ionic composition of human plaque and saliva after a fluoride rinse and a subsequent sucrose application, and to interpret the results using these previous observations. Subjects (n = 13) accumulated plaque for 48 h, and then rinsed with a high potency 228 ppm controlled release two component fluoride rinse or received no rinse. Sixty minutes later upper and lower molar plaque samples and 1-minute saliva samples were collected. The subjects then rinsed with 10 mass % sucrose and 7 min later, a second set of plaque and saliva samples were collected. Fluid obtained from these samples by centrifugation was then for pH, free calcium, phosphate, organic acids and fluoride analyzed using micro techniques. Results showed that in spite of a very high plaque fluid and salivary fluoride concentration in the treated samples; only a modest effect (about a 20 mole % decrease) on post sucrose plaque lactate production, or enamel saturation was observed 7 min after the sucrose rinse. However, a somewhat larger effect ( 0.3 unit) effect on pH was observed. Sucrose rinsing produced a pH mediated increase in free calcium, but net decrease in phosphate and fluoride, which, apparently in view of the previous studies showing a pH mediated increase in the latter ions, was due to salivary clearance or diffusive loss into the water phase of the rinses. Similarly the site distribution of all ions appeared to be not only controlled by these factors (clearance and pH) but also by salivary pooling as well as pooling of fluoride and sucrose rinse components (including water). Although this study demonstrated that many of the mechanisms suggested for fluoride cariostasis can be observed in vivo in plaque and saliva, the oral distribution of rinse components (fluoride, sucrose and water), as well as the clearance of ions into these components require further study if a comprehensive understanding of the relative importance these mechanisms is to be obtained.
Caries Research


caries, fluoride, labile ions, plaque, saliva


Vogel, G. , Zhang, Z. , Chow, L. and Galvin, A. (2002), Changes in Lactate and Other Ions in Plaque and Saliva After a Fluoride Rinse and Subsequent Sucrose Administration, Caries Research, [online], (Accessed April 14, 2024)
Created January 1, 2002, Updated February 19, 2017