This single-center, randomized, double-blind, three-period crossover in situ study evaluated the enamel remineralization potential and fluoride bioavailability of three dentifrices-one fluoride-free negative control, one positive control with 0.243% sodium fluoride, and one investigational dentifrice containing 0.243% sodium fluoride and 20% sodium bicarbonate. Healthy adult subjects wore a palatal acrylic appliance containing demineralized enamel specimens for three 9-day treatment periods, during which in vivo brushing/slurry exposure and ex vivo sucrose challenges were performed. Outcomes included percent surface microhardness recovery (%SMHR) and post-treatment enamel fluoride concentration.

This in situ intraoral appliance (IOA) model evaluates anticaries potential by exposing demineralized enamel specimens to oral conditions while allowing for ex vivo treatment assessments. Subjects wore acrylic palatal appliances containing four enamel specimens covered with steel gauze to promote plaque formation. Each of the three treatment periods lasted nine days and included twice-daily toothbrushing and dentifrice slurry swishing, plus three daily sucrose challenges. A minimum 4-day fluoride-free washout preceded each period. Post-treatment specimens were analyzed for %SMHR and enamel fluoride concentration.

Inclusion Criteria:

• Adults ≥18 years
• Good general and oral health
• Normal unstimulated salivary flow (≥1.5 mL/5 min)
• Functional dentition
• Oral conditions adequate to support the palatal appliance
• Ability to comply with brushing, slurry, appliance wear, and sucrose challenge procedures

Exclusion Criteria:

• Inability to tolerate appliance
• Oral pathology that interferes with participation
• Antibiotic use that violates withdrawal criteria
• Use of fluoride toothpaste during washout
• Participation in another appliance study in the past 4 weeks

The sponsor does not plan to share individual participant data (IPD) from this study. Summary results will be provided as required, but no de-identified datasets or additional supporting documents will be made available.