Assessment of dental-caries using optical coherence tomography

We employed OCT imaging technique to study the human teeth infected with the caries lesion in fit and fissure. A time domain OCT system using a rapid-scanning optical delay line enabled high speed imaging of extracted teeth. The OCT images presented the morphological feature and caries-involved area of the dental structure with a high resolution of ~14 μm. The OCT images could be utilized to diagnose the disease, while a signal along the axial direction could provide quantitative analysis of the disease based on the reflectivity differences in the specimen. We investigated the influence of caries in human teeth with several imaging tools such as light illuminating exam, digital intra-oral radiography and electron probe micro analyzer, which provided the distributions of chemical compositions, mainly calcium and phosphate in hard tissues. The biochemical changes acquired from EPMA and the morphological features acquired from OCT in the early stage of caries were compared and analyzed to present more objectively practical index for translating the degree of caries.