A method for forming an enhanced image of a tooth comprising: a) obtaining fluorescence image data from the tooth by: (i) directing incident light toward the tooth; (ii) sensing fluorescent emission from the tooth; (iii) storing a fluorescence image data value for each pixel position in the fluorescence image;, b) obtaining reflectance image data from the tooth by: (i) directing incident light toward the tooth; (ii) sensing back-scattered reflectance light from the tooth; (iii) storing a reflectance image data value for each pixel position in the reflectance image; characterised in that the method further comprises c) combining each pixel in the fluorescence image data with its corresponding pixel in the reflectance image data by: (i) subtracting an offset to the reflectance image data value to generate an offset reflectance image data value, wherein the offset approximates a difference in intensity between the fluorescence image data distribution and the reflectance image data distribution; (ii) after subtracting the offset, computing an enhanced image data value according to a difference between the fluorescence image data value and the offset reflectance image data value; and whereby the enhanced image is formed from a resulting pixel array of enhanced image data values. a) obtaining fluorescence image data from the tooth by: (i) directing incident light toward the tooth; (ii) sensing fluorescent emission from the tooth; (iii) storing a fluorescence image data value for each pixel position in the fluorescence image;, (i) directing incident light toward the tooth; (ii) sensing fluorescent emission from the tooth; (iii) storing a fluorescence image data value for each pixel position in the fluorescence image;, b) obtaining reflectance image data from the tooth by: (i) directing incident light toward the tooth; (ii) sensing back-scattered reflectance light from the tooth; (iii) storing a reflectance image data value for each pixel position in the reflectance image; characterised in that the method further comprises (i) directing incident light toward the tooth; (ii) sensing back-scattered reflectance light from the tooth; (iii) storing a reflectance image data value for each pixel position in the reflectance image; c) combining each pixel in the fluorescence image data with its corresponding pixel in the reflectance image data by: (i) subtracting an offset to the reflectance image data value to generate an offset reflectance image data value, wherein the offset approximates a difference in intensity between the fluorescence image data distribution and the reflectance image data distribution; (ii) after subtracting the offset, computing an enhanced image data value according to a difference between the fluorescence image data value and the offset reflectance image data value; and whereby the enhanced image is formed from a resulting pixel array of enhanced image data values. (i) subtracting an offset to the reflectance image data value to generate an offset reflectance image data value, wherein the offset approximates a difference in intensity between the fluorescence image data distribution and the reflectance image data distribution; (ii) after subtracting the offset, computing an enhanced image data value according to a difference between the fluorescence image data value and the offset reflectance image data value; and whereby the enhanced image is formed from a resulting pixel array of enhanced image data values.