Diagnostics of tongue coating using autofluorescence

A clinical study of possibilities and limitations

Abstract

In the present study, the VELscope® autofluorescence device was used in addition to the Winkel Tongue Coating Index (WTCI) to evaluate tongue coating; a corresponding index was developed for evaluation with VELscope®. The distinct orange fluorescence of the tongue dorsum caused by autofluorescent bacterially colonized areas motivates halitosis patients to optimize tongue hygiene. The tongue dorsum of 100 volunteers (35 males, 65 females, average age 51 years) was photographed with and without the autofluorescence device. On the computer, all tongue photographs were divided into sextants. These pictures were evaluated randomly by six investigators (5 inexperienced and the experienced head of the halitosis consultation hour). Both methods localized the highest coating density in the mid posterior area of the tongue. Significant differences were found between the WTCI and the VELscope® Index (p < 0.001). While WTCI was more sensitive in discriminating between absence and presence of sparse coating, VELscope® imaging was relatively insensitive to sparse coating, but better detected dense coating than did WTCI. For both methods, inexperienced and experienced examiners achieved comparable results (kappa coefficient without VELscope® 0.654, with VELscope® 0.672). The VELscope® device can complement tongue coating diagnosis, but it cannot replace the Winkel Tongue Coating Index.