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

Abstract 

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 12mm² enamel windows made on ten extracted bovine teeth, developed stains in 6-min cycles (2min 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.

Keywords: QLF, Fluorescence, Digital imaging, Staining, Tooth-whitening