<title>Determination of the optical parameters of dentin from spatially resolved reflectance and transmittance measurements</title>

Abstract

Measurements of the absolute spatially resolved reflectance and transmittance from dentin slabs were performed using a HeNe laser at λ = 633 mm as source and a CCD camera as detector. Solid phantom slabs were used to test the experimental setup and to enable absolute measurements. The reduced scattering and absorption coefficients were derived by applying a solution of the diffusion theory for a slab geometry as theoretical model. Monte Carlo simulations were used to investigate the validity of the diffusion solution. Compared to other biological tissues large values were found for the reduced scattering coefficient of dry dentin slabs, in which the tubuli were parallel to the slab extension. In addition, we measured a strong dependence of the optical properties on the water content of the dentin slabs. We also found that the anisotropic structure of dentin strongly influences the light propagation and, thus, the derived optical properties.

Equi-intensity distribution of optical reflectance in a fibrous turbid medium

“…In many studies, the tissue sample can be assumed as isotropic, i.e., its optical properties are independent of photon incident directions. However, this is not true in some biological tissues such as muscle [1], skin [2], dentin [3], and white matter [4], where anisotropic fibrous or tubular structures are abundant. For example, Marquez et al [1] found that optical properties of the chicken breast differed significantly when measured parallel or perpendicular to the muscle fiber orientation.…”