New In Situ Model Design for Caries and Erosion

This study will test simultaneously and independently two novel in situ models, one for caries and one for erosive tooth wear (ETW), based on the simulation of these dental conditions on enamel specimens placed on 3D-printed mandibular appliances. Caries simulation will be done on the right side (color-coded blue) of the appliance, while ETW on the left side (color-coded red) and their outcomes evaluated independently. The study aims at testing the safety, compliance and F-efficacy (dose-response) of the models. The study will follow a double-blind, single-center, 3-way within-subject crossover design. Treatments will consist of dentifrices, or toothpastes, (1150 ppm F as sodium fluoride, 250 ppm F as sodium fluoride and 0 ppm F/Negative Control) used twice a day.

Inclusion Criteria: * In order to participate subjects must: 1. Provide voluntary, written informed consent; 2. Be between 18 and 65 years old; 3. Understand and be willing, able and likely to comply with all study procedures and restrictions; 4. Be willing and capable of wearing a custom-made removable mandibular appliance 24 hours a day for three (3), three-week treatment periods; 5. Be in good medical and dental health with no active caries or periodontal disease; Note: subjects presenting at screening with caries may continue in the study if their carious lesions are restored prior to beginning treatment 1; and, 6. Have a salivary flow rate in the range of normal values (unstimulated whole saliva flow rate ≥ 0.2 mL/min; gum base stimulated whole saliva flow rate ≥ 0.8 mL/min); 7. Have an adequate number of teeth and space to accommodate the custom-made removable mandibular appliance, as per the study PI/study dentist's discretion. Exclusion Criteria: * No subject may: 1. Be pregnant, intending to become pregnant during the study period or breast feeding; 2. Have any medical condition that could be expected to interfere with the subject's safety during the study period (including temporomandibular disorders); 3. Be taking antibiotics during the study period, or have taken antibiotics in the two weeks prior to the beginning treatment 1; 4. Participated in another clinical study or receipt of an investigational drug within 30 days of beginning treatment 1; 5. Be taking fluoride supplements, required to use a fluoride mouthrinse or have received a professional fluoride treatment in the two weeks preceding specimen placement; or, 6. Have a history of metal allergies.