Clinical assessment of oral malodor using autofluorescence of tongue coating

• QLF-D can visualize and detect tongue coating as red fluorescence.
• Tongue fluorescence detected by QLF-D is correlated to the severity of oral malodor.
• IF score can be used to evaluate oral malodor by quantifying tongue coating fluorescence.

ObjectivesThe aim of this study was to evaluate whether a new method using quantitative light-induced fluorescence-digital (QLF-D) was appropriate for the diagnosis of oral malodor by quantifying the fluorescence of tongue coating.MethodsThis study examined 103 healthy subjects who have an oral malodor as a main complaint. The levels of oral malodor were measured by organoleptic scores (OLS) and volatile sulfur compound (VSC) levels. The fluorescent tongue coating images captured by QLF-D were quantified as the integrated fluorescence score (IF score) by multiplying the intensity and area of fluorescence. The correlations between the fluorescence parameters and OLS as well as VSC levels and the diagnostic accuracy of the IF score were evaluated.ResultsThe IF score of tongue coating showed a significant positive correlation with the OLS (r = 0.54, p < 0.01) and the VSC levels (r = 0.49, p < 0.01). This score was significantly differed with the level of oral malodor (p < 0.001), and its AUC was 0.72 in identifying the patient with definite oral malodor (≥OLS 2).ConclusionsA new method quantifying tongue coating fluorescence detected by QLF-D can be used to diagnose oral malodor and assess its severity in the clinical practice.