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Changes in the hydration state of the enamel, sound or deficient, would change some of its optical qualities, such as its light scattering and, subsequently, its fluorescence. In this study, the rate of fluorescence loss in incipient enamel lesions with different kinds of surface layers was measured while gradually dehydrating. Incipient enamel lesions were prepared in vitro and assigned into one of three groups: group A was kept humid to serve as a control, group B was exposed to a remineralizing solution, group C was exposed to the same solution + 5 min daily fluoride treatment (30% wt of 1,000 ppm NaF dentifrice slurry). After 10 weeks, enamel fluorescence was measured for all the lesions immediately after removal from the liquids, and once every min for 10 min, thereafter once every 5 min until 30 min. All the groups showed a rapid drop in fluorescence after a few minutes. The time elapsed before the lesions reached a steady fluorescence level was 2.4±0.5, 2.7±0.5 and 6.0±1.1 min for groups A, B, and C, respectively. There was a significant difference between groups A and B and group C (p<0.01). It was concluded that different approaches of remineralization resulted in different patterns of porosity in the surface layer of enamel lesions, thus, changing its physical properties. Such findings should be considered when planning a prophylactic or therapeutic treatment of incipient enamel lesions, also when evaluating the response to that treatment, since the porosity of the surface layer of incipient lesions has been reported to play a significant role in the remineralization process. Supported by the Swedish Patent Revenue Research Fund. |