A digital tongue imaging system for tongue coating evaluation in patients with oral malodour.

OBJECTIVE Several simple visual methods have been developed for assessing tongue coating, but it is difficult to eliminate biases associated with these. The digital tongue imaging system (DTIS) was designed to acquire tongue surface images using a digital camera under controlled conditions, and to calculate tongue coating area. The aim of this study was to evaluate the potential of DTIS for clinical use by comparing it with the Winkel tongue coating index (WTCI). MATERIALS AND METHODS Forty participants with oral malodour were rated on WTCI by two independent examiners, and photographs of their tongues were assessed using the DTIS. The photographs were also rated by the examiners (blinded to in vivo WTCI and DTIS statuses). RESULTS Agreements between in vivo WTCI ratings and DTIS assessments were relatively high at r = 0.561 for one examiner and r = 0.736 for the other (P < 0.01), while agreements between the in vivo WTCI ratings and tongue photograph-based ratings were also high at r = 0.645 for one examiner and r = 0.742 (P < 0.01) for the other. CONCLUSIONS Digital tongue imaging system was found to be highly reliable and as having potential clinical applications. However, the algorithm for determining in vivo tongue coating status requires improvement.