Standard methods of carries detection, such as visual examination combined with tactile explorer response and radiographs, are associated with limitations including failure in detection of early bacterial activity inside fissures, below the surface of the tooth or underneath the surfaces of restorations. To overcome these limitations, a new diagnostic technique, known as the quantitative light-induced fluorescence (QLFTM), has been rolled out.
The QLFTM technique, which works on the principle of fluorescence promises to offer additional visual information for early detection of carries and bacterial activity. The QLFTM technique allows visual contrast of sound and carious enamel and dentin. Several studies have proven that QLFTM is superior to standard processes of carries detection. Use of QLFTM helps in early lesion detection (depicted by green fluorescent light) and follow-up of these lesions may help in determining whether demineralization or remineralization is occurring in the teeth. The QLFTM technique also allows detection of bacterial activity, which can be identified by the presence of red fluorescence from white spots of demineralization. This red fluorescence corresponds to the progression of lesion to a state where the enamel has become so porous that bacterial metabolites (if not the bacteria themselves) can penetrate the lesion.