Effects of DCPD/APF application and prolonged exposure to fluoride on caries-like lesion formation in vitro.

The ability of a topical fluoride regimen consisting of a 4-min application of a saturated dicalcium phosphate dihydrate (DCPD) solution followed by a 4-min application of 1.23% acidulated phosphate fluoride (APF) to inhibit caries-like lesion formation in sound enamel was compared to that of a 4-min application of APF. Following the applications, specimens were washed for 24 h in an inorganic wash solution or for 28 days in a wash solution containing 1 ppm fluoride. The mean overall lesion depth for specimens treated with APF and washed for 28 days was significantly greater than that for the group treated with DCPD/APF and washed for 28 days, and for the group treated with APF and washed for 24 h (p less than 0.05). For those specimens washed for 24 h, the mean width of the surface zone was greater (p less than 0.05) for the DCPD/APF group compared to the APF group.