Abstract: Apparatus and method for imaging a tooth. The apparatus includes: illumination means arranged to generate first and second infra-red light; and image data acquisition means arranged for receiving infra-red light originating from the illumination means and returned from an illuminated tooth. The image data acquisition means includes infra-red pixel sensor means responsive to said returned infra-red light to generate image pixel values for a first image of the illuminated tooth using first infra-red light and for a second image of the illuminated tooth using second infra-red light. The apparatus further includes data processing means to use one or more image pixel values of the first image to calculate a first reflectance value, and to use one or more image pixel values of the second image to calculate a second reflectance value, and to determine from the first and second reflectance values a measure of the degree of enamel lesion (Se) and/or dentin lesion (Sd) present in the part.