Effect of different application frequencies of CPP-ACP and fluoride dentifrice on demineralized enamel: a laboratory study.

PURPOSE: To evaluate the effect of different application frequencies of dentifrices containing CPP-ACP and fluoride on enamel demineralization inhibition using a pH cycling model. METHODS: A total of 120 enamel blocks obtained from permanent human third molars were divided into eight groups according to the treatment and number of times that the dentifrice slurry was applied (three or five times): Control--Dentifrice without Fluoride (CO3 and CO5); Fluoride Dentifrice (FD3 and FD5--commercial dentifrice 1100 ppm as NaF); MI Paste (MP3 and MP5--Recaldent) and MI Paste Plus (MPP3 and MPP5--Recaldent 900 ppm as NaF). The specimens were alternately soaked in a demineralizing solution for 6 hours and in a remineralizing solution for 18 hours for 5 days. The treatments were applied three or five times for 60 seconds after the de-remineralization period. The dentifrice slurries were prepared with deionized water, in a 1:3 proportion (wt%). Demineralized enamel changes were analyzed by surface microhardness (SMH) and 3D-profilometry. Data were analyzed by two-way and one-way ANOVA and Tukey's HSD post hoc test (α = 0.05). RESULTS: The percentage change of SMH (%SMH) was similar for all treatment groups except between MP5 < CO3 and CO5 (P < 0.05). The enamel samples treated with CCP-ACP topical paste showed smoother surfaces than those of control and fluoride dentifrice.