Intra-oral imaging apparatus and/or method embodiments can provide digital dental reflectance images used to identify selected areas of interest (AOI) within a dental region of interest (ROD having selected image characteristics for both hemo-globin's total concentration and oxygenation level. In one embodiment, reflectance images can determine relative total hemoglobin using at least a wavelength band that includes an isobestic wavelength for absorption coefficients of oxyhemoglobin (HbO2) and deoxyhemoglobin (Hb). In one embodiment, intra-oral imaging apparatus and/or method embodiments can use reflectance images of a dental region at least at three wavelengths； a control logic processor for processing the reflectance images to determine relative tHb and its relative oxygenation level and/or identify disease areas having periodontal tissues condition； and a display for displaying periodontal tissues or a visual indication of the areas having selected imaging characteristic determined by the reflectance images.
