Optical detection of the potential for tooth discoloration from children's beverages by quantitative light-induced fluorescence technology

Background: Some beverages are known to cause extrinsic staining on the tooth. This study investigated the degree of pigmentation caused by children's acidic beverages, and to confirm the possibility of the quantitative light-induced fluorescence (QLF) technology in assessing staining of the tooth. Methods: Bovine tooth specimens were subjected to an 8-day pH-cycling model, using six children's beverages (experimental groups) and a cola (control group), and a remineralizing solution. Before and after the pH-cycling, white-light and fluorescence images of the enamel surface were photographed with a QLF to evaluate color change (ΔE_after) and fluorescence loss (ΔF_after), respectively. Paired t-test was used to compare the tooth colors obtained before and after the pH-cycling. Spearman correlation analysis was performed to examine the correlation between the ΔE_after and ΔF_after values. Results: Median ΔE_after values of all the beverages ranged from 1.33 to 20.42, showing the greatest value in Koal-Koal Koala™ (KKK, p < 0.001). The ΔE_after was correlated with ΔF_after value negatively (ρ=−0.611, p < 0.001). The median ΔF_after varied by beverages (−38.86–0.00) and KKK caused the greatest value. Conclusions: The cola and 6 children's beverages showed the possibility for discoloration on the tooth. The QLF technology may enable monitoring the discoloration induced on the tooth surface by acidic beverage.