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What is Which of the following is not true about DIAGNOdent? and explain in detail?
DIAGNOdent is based on the phenomenon of laser-induced fluorescence of the enamel where porphyrins present in carious tissue fluoresce when stimulated by DIAGNOdent. DIAGNOdent may not provide accurate estimation of caries lesion depth since it is detecting porphyrin fluorescence and not mineral content of enamel crystal structure. 
The Canary System uses energy conversion technology (PTR-LUM) to image and examine the tooth. Pulses of laser light are aimed at the tooth, and the light is then converted to heat (Photothermal Radiometry or PTR) and light (luminescence or LUM), which are emitted from the tooth surface in response to the modulated pulses.