The purpose of this trial is to evaluate the anticaries remineralizing potential of a toothpaste containing 500 ppm fluoride plus fTCP technology relative to a commercially available toothpaste via a double-blind cross-over in situ (or intra-oral) clinical model, whereby approved human participants will wear an orthodontic appliance fitted with an enamel specimen for the duration of a leg (28 days). There will be two test legs.

Inclusion Criteria:

• 30 adult subjects (between 18-50 years of age)

This in situ study will recruit 30 adult subjects (between 18-50 years of age). No potential subject will be excluded from this study, regardless of their gender or racial/ethnic origins. However, it is expected that about 18 (60%) of the 30 subjects in the trial will be women. This distribution will allow for meaningful comparisons between gender groups. We will recruit patients attending the clinics of UTHSCSA dental school clinics, which reflect the ethnic mix of the area the clinics serve. However, majority of subjects will be Hispanic due to the high Hispanic prevalence (57.8%) in San Antonio. Thus, minorities will be included at a similar rate to that in the general population attending for dental care,