An imaging probe was employed to acquire images from the occlusal surface. It consisted of a 25-mm objective lens, a ½ inch in diameter tube 5” long with a relay lens, a mirror and light delivery optics. A high sensitivity InGaAs (Indium gallium arsenide) imaging camera, Model SU320KTSX (Sensors Unlimited, Princeton, NJ) was used to collect all the images. For comfort and stability, the video camera/handpiece assembly was mounted onto the examiner’s forearm as shown in Fig. 3 and the probes were held by the ½ tube of the probe. Since lesions are detected by differences in optical contrast uniform illumination is critical for NIR imaging. The probe shown in Fig. 3 is placed directly over the tooth and optical fibers coupled to Teflon optical diffusers in two arms directed the NIR light to just above the gingival tissues on the facial and lingual side of the tooth and the mirror directed the light to the imager. The system provided uniform illumination of the crown and the sound enamel was visible as a ring of higher intensity around the central dentin core of the tooth. Occlusal lesions were visible as dark areas in the occlusal pits and fissures. Light was provided by two 1310-nm superluminescent diodes (SLD) from (Optospeed, Zurich, Switzerland), with an output power of 15 mW and a 35-nm bandwidth. The power was determined empirically by experimenting with various settings and the bandwidth was chosen because the use of broadband SLD’s reduces speckle noise and the related image degradation that is common with narrow bandwidth light sources. If it was necessary to remove bubbles on the teeth to be examined, they were gently dried with a stream of air from a dental unit air syringe and video (8-bit) was acquired as the imaging handpiece was passed over the tooth.