A technique for obtaining information regarding a state of periodontal tissue involves deriving a substantially whole curve measure of similarity of an observed bandshape of an isolated spectral component attributed to water within the infrared region. Subtle variations in the bandshape of the water bands have been found to correlate with inflammatory periodontal diseases and using whole curve measures such as weighted integrals or measure of fit parameters these variations can be detected and used to classify periodontal tissues.
