In situ methods of evaluating the potential of a test composition to inhibit demineralization of the tooth enamel and/or to promote remineralization of acid-softened enamel using quantitative light fluorescence (QLF), e.g., by using an intra-oral appliance comprising tooth substrates to permit application of test composition to the substrate when in the mouth and erosive challenge when outside the mouth, and measuring the degree of mineralization or demineralization of the tooth substrate by in the presence and absence of treatment with the test composition.
