This study will be a cross-over single blinded clinical study to evaluate the in vitro fluoride release of three different brands of 5% NaF varnish. The goal of this study is to determine if different formulations of varnish lead to differing amounts of fluoride release. Despite their similar concentrations of NaF (5%), some in vitro data have suggested that they may differ in the amount of fluoride release. Determining fluoride release of these varnishes in vivo is important in assessing both the safety and efficacy of the product.

This study will be a cross-over single blinded clinical study to evaluate the in vitro fluoride release of three different brands of 5% NaF varnish. Subjects will be recruited at the University of Michigan School of Dentistry and will participate in a 15 minute clinical session at the beginning of each study arm, followed by 6 saliva collection recalls. During these sessions a fluoride varnish or placebo will be applied to their teeth, and subsequent salivary samples will be taken 1 hour, 4 hours, 6 hours, 24 hours, and 48 hours after the application. All subjects will receive 3 commercially available varnishes, and a placebo varnish. Between applications there will be a minimum of 2 weeks wash-out period. The goal of this study is to determine if different formulations of varnish lead to differing amounts of fluoride release. Despite their similar concentrations of NaF (5%), some in vitro data have suggested that they may differ in the amount of fluoride release. Determining fluoride release of these varnishes in vivo is important in assessing both the safety and efficacy of the product.

Specific Aims

1. Determine the concentration of fluoride available in the oral cavity at different time periods after the application of three different 5% NaF varnishes as measured in unstimulated human saliva.
2. Compare the different patterns of fluoride release from each of the varnishes by comparing the fluoride concentration in saliva at corresponding time periods .
3. Evaluate the validity of an in vitro model used to measure fluoride release from varnishes.

Percentage difference in fluoride release between the in vivo and in vitro data obtained from the same products will be compared. Because the comparison of different patterns of fluoride release from the varnishes is accomplished by analyzing the fluoride available concentration levels, it was an error to list that secondary aim as a secondary - or indeed any sort of outcome measure. The outcome measure data for "patterns of fluoride release" is exactly that which has been fully disclosed in the Primary Outcome Measure data tables. Therefore the secondary outcome measure previously listed: Compare the different patterns of fluoride release from each of the varnishes, which was really never properly an outcome measure, but an aim, has been deleted, with no loss of data transparency.

Inclusion Criteria:

• All subjects between 18-65 years of age and do not fall under any of the exclusion criteria

Exclusion Criteria:

• Subjects with less than 20 teeth
• Subjects with significant untreated disease to include gum disease, extensive decay, or the need for pre-medication prior to dental treatment
• Pregnant or lactating women
• Subjects with a history of allergy to materials to be used in the study
• Subjects unable to produce adequate saliva for sampling
• Subjects deemed low risk for dental caries (no history of restorative work or presence of caries lesions)
• Subjects unable to be available for all 4 cycles of the study

6 months