1. A method for identifying one or more tooth regions, comprising: generating a first threshold image from a first image of a tooth by selecting intensity data values higher than a first predetermined threshold value c 1 ; generating a second threshold image from a second image of the tooth by selecting intensity data values higher than a second predetermined threshold value c 2 , wherein the first image is a grayscale fluorescence image of the tooth and the second image is a grayscale reflectance image of the tooth; generating a preliminary tooth regions image that defines at least a first tooth region from the intersection of the first and second threshold images; generating a reference binary image from the first image by selecting intensity data values higher than a third predetermined threshold value c 3 , wherein threshold value c 3 exceeds threshold value c 1 ; generating a refined tooth regions image from the at least the first tooth region in the preliminary tooth regions image, wherein the at least the first tooth region is connected to objects in the reference binary image; processing the refined tooth regions image and generating a processed refined tooth regions image, wherein generating the processed refined tooth regions image includes removing small areas and filling holes resulting from the thresholding operation; and displaying, storing, or transmitting the refined tooth regions image.