Comparison of quantitative light-induced fluorescence (QLF) and digital imaging applied for the detection and quantification of staining and stain removal on teeth

Objectives This study compares the use of QLF with digital imaging in the detection and quantification of the development and removal of stain on teeth. Methods Two experimental phases, tooth staining and tooth whitening, conducted in vitro on labial 12 mm2 enamel windows made on ten extracted bovine teeth, developed stains in 6-min cycles (2 min in each solution) using artificial saliva, chlorhexidine and tea solutions and removed them using sodium perborate monohydrate in 2-min cycle monitored at the end of each cycle with QLF (Inspektor Research Systems, NL) and digital photography (Fuji, Japan). The stain values were quantified as ΔQ derived from QLF and ΔE from digital imaging. This was observed by the two methods correlated with Pearson correlation coefficient (r). Regression equations (R2) were also obtained. Results For both staining and stain removal there was a statistically significant (p < 0.01) reverse correlation between ΔQ values for QLF (r = −0.924, R2 = 85.4%) and ΔE values for digital imaging (r = −0.994, R2 = 98.8%), respectively. Conclusion QLF showed a high correlation with digital imaging as a technique for detecting and monitoring tooth stains and tooth whitening in vitro. The potential for QLF with further development as a tool for monitoring staining and whitening of teeth may be possible in vivo in addition to the diagnostic ability for caries detection.