HENE-LASER LIGHT-SCATTERING BY HUMAN DENTAL ENAMEL

Knowledge of the optical properties of tooth enamel and an understandi ng of the origin of these properties are necessary for the development of new optical methods for caries diagnosis and the measurement of to oth color. We measured the scattering intensity functions for HeNe-las er light of 80- to 100-mu m-thick human dental enamel slabs. The asymm etry factors were calculated to be g = 0.68 at 633 nm. By measuring th e collimated beam attenuation, we determined the scattering coefficien t to be s = 6.6 mm(-1). From Fraunhofer diffraction patterns, obtained from transmission of the laser beam, we calculated the periodicity of the prismatic structure as 5.4 mu m. We present a model containing sc attering by crystals and by prisms. It shows that the prisms are the m ost important scatterers but that the crystals are responsible for the back-scattering.