Changes in the optical properties of dental enamel at 1310 nm after demineralization

The first step towards the development of clinically useful optical diagnostic systems is achieving a fundamental understanding of how light propagates through the tooth. The optical properties of dental hard tissue needed to describe light propagation in those tissues have not been determined in the near-IR. Although it is well known that the overall magnitude of light scattering increases due to demineralization of tooth enamel and dentin, the specific nature of those changes, namely quantitative changes in the optical constants and the scattering phase function have not been determined. The objective of this study was to determine the changes in the optical constants and the scattering anisotropy of dental enamel after artificial demineralization at 1310-nm. During the caries process micropores are formed in the lesion due to partial dissolution of the individual mineral crystals. Such small pores are likely to behave as scattering centers, strongly scattering visible and near-IR light. In this study, demineralization increased the scattering coefficient more than two orders of magnitude at 1310-nm and the scattering due to the scattering centers (micropores) is highly forward directed.