Measurement of Dental Erosion Using Quantitative Light-Induced Fluorescence

The use of Quantitative Light-Induced Fluorescence (QLF) to detect and quantitatively monitor dental caries is now well established, and more recent studies suggest its possible ability to measure dental erosion. Objective: To investigate the ability of QLF to detect and quantify dental erosion, and correlate it with transverse microradiography (TMR). Methods: 13 bovine incisors and 13 human molars were prepared and each tooth was cut into two halves. The slabs were coated with non-fluorescent acid-resistant nail varnish except for an exposed window on buccal surface. Erosion was created by immersing the teeth in agitated orange juice (pH 3.5) at room temperature. Erosion was quantified in one half of each tooth with QLF and in the second half with TMR as follows. After initial 30 minutes (60 minutes for human teeth) of erosive challenge, QLF image was taken from one half of each tooth and fluorescence loss (DQ) quantified, while an enamel section was cut from the second half and microradiographed. This procedure was repeated every 30 minutes for a total period of 300 minutes. From microradiographs the depth of the crater (CD) created by erosion, and the mineral loss, first for the entire eroded lesion (DZ_e) and then for only the demineralised tissue at the lesion base (DZ_b) were determined. Results: Squared Pearson correlation coefficient (r²) indicated a linear correlation between DQ and DZ_e in both bovine teeth (r²=0.98; regression equation, DQ = 0.83 + 0.01DZ), and human teeth (r²=0.99; DQ = -3.52 + 0.01DZ). A stronger correlation was observed between DQ and CD [r²=0.99 (bovine); r²=0.96 (human)], than between DQ and DZ_b [r²=0.81 (bovine); r²=0.79 (human)]. Conclusion: QLF was able to monitor the mineral lost during erosive challenge, due mainly to its ability to measure the change in depth of the crater formed during the erosive attack.