Clinical Study to Evaluate Remineralization Using an in Situ Model.

This Phase III, randomized, single-center, triple-blind, crossover clinical study will evaluate the remineralization efficacy of three dentifrices on artificially induced initial enamel caries lesions. The research will involve 30 healthy participants aged 18 to 70 years who meet strict inclusion criteria. The experimental design will utilize an in situ model where participants will wear custom-made removable mandibular intraoral appliances containing four human enamel blocks with pre-formed artificial caries lesions. These lesions will be created laboratory-side using an acidified gel demineralization system before the blocks are mounted into the appliances. The study will follow a nine-week timeline, divided into three 14-day experimental phases separated by 7-day washout periods to eliminate carryover effects, totaling 8 visits. During the treatment phases, subjects will be randomly assigned to a sequence of three test products: a test dentifrice with 750 ppm MFP, a positive control with 1450 ppm MFP, and a fluoride-free negative control. Each participant will receive a soft-bristle toothbrush and the assigned toothpastes. The primary outcome will be the change in integrated mineral loss measured by transverse microradiography (TMR). Baseline mineral loss will be established from a slice of each block before intraoral exposure and compared to post-treatment analysis of the adjacent tissue. Secondary outcomes will include changes in lesion depth and fluorescence loss parameters assessed via Quantitative Light-induced Fluorescence (QLF). Statistical analysis will be performed using a linear mixed-effects ANCOVA model to confirm the hypothesis that the 750 ppm MFP dentifrice promotes significantly greater remineralization than the negative control, with effects lower than or comparable to the high-fluoride positive control.