Calcium Prerinse before Fluoride Rinse Reduces Enamel Demineralization: An in situ Caries Study

A calcium (Ca) prerinse before a fluoride (F) rinse has been shown to increase oral F levels. We tested the anticaries effect of this combination in a dose-response in situ caries model. In a double-blind, crossover experiment, 10 volunteers carried enamel slabs in palatal appliances for 14 days, during which they rinsed twice/day with one of four rinse combinations: (1) a placebo prerinse (150 mm sodium lactate) followed by a distilled water rinse (negative control); (2) a placebo prerinse followed by a 250 ppm F rinse; (3) a placebo prerinse followed by a 1,000 ppm F rinse, or (4) a Ca prerinse (150 mm Ca, as calcium lactate) followed by a 250 ppm F rinse. Sucrose solution was dripped onto the slabs 8x/day to simulate a high cariogenic challenge. The percent surface hardness loss (%SHL) was significantly lower in the Ca prerinse used with the 250 ppm F rinse group (%SHL = 38.0 +/- 21.0) when compared with the F rinse alone (%SHL = 59.5 +/- 24.1) and similar to the 1,000 ppm F rinse group (%SHL = 42.0 +/- 18.3). Compared with the 250 ppm F rinse, the Ca pre rinse increased biofilm fluid F only twice (nonsignificant). However, it greatly increased F in biofilm solids (similar to 22x). The Ca prerinse had little effect on loosely or firmly bound enamel F. The results showed an increased level of protection against demineralization by the use of a Ca prerinse, which seems to be caused by the enhancement of F concentration in the biofilm. (C) 2016 S. Karger AG, Basel (AU)