Comparison of the Effects of Two Topical Fluoride Regimens

were worn for 96 hr by seven adult males who brushed daily with a F-free dentifrice. Test slabs were brushed with a NaF dentifrice 4 x / day or with the same dentifrice 4 x /day and a 0. 02% APF mouthrinse and a 0.4% SnF2 gel which were applied once/day for three days. The natural dentition was also brushed with the NaF dentifrice during both test periods. Microhardness testing was performed on sound enamel, and after acid-softening, intra-oral exposure (IOE), and acid resistance testing (ART) in 0. 01 moliL lactic acid at pH 4. 0 for 24 hr. Control and test slabs were etched with 0.5 mol/L HC104forfrom 15 to 60 sec. The F content was measured with a F electrode and P04 by spectrophotometry. Contact microradiography and image analyses were performed on control and test slabs so that changes in mineral content resulting from treatment could be assessed. Both test