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The primary objective was to determine if dehydration of demineralized enamel affects fluorescence as measured with QLF. A secondary objective was to evaluate a new QLF camera. Forty 3-mm-diameter enamel specimens were prepared from extracted human teeth. Images were acquired with both an old and new QLF camera after 0, 3, 5, 10, 15, 20, 25, and 30 min of dehydration. Specimens were then equally divided into four demineralization (demin) groups and placed in an in vitro microbial caries model for either 1, 2, 4 or 6 days. QLF images were acquired of the demineralized specimens as described above. The specimens were sectioned in half and the lesion depth measured with confocal laser scanning microscopy. The absolute fluorescence intensity (AF) of all specimens for both sound and demineralized images was determined using QLF software. For the 1-, 2-, 4- or 6-day demin groups, the lesion depth was 1.24B3.93, 14.19B2.41, 19.60B7.97, or 28.97B12.23 Ìm, respectively. AF rapidly decreased during the first 3 min of dehydration for both the sound and demineralized enamel; however the effect appeared to be much more pronounced for the demineralized enamel. AF continued to decrease from 3 to 30 min of dehydration for all groups, although to a lesser extent. The pattern of AF change was very similar among the different demin groups, suggesting that enamel dehydration may not be helpful in differentiating among different-sized active lesions. Overall, the new QLF camera was found to be superior to the old camera and had a higher correlation with lesion depth. |