Scattering anisotropy measurements in dental tissues and biomaterials

Abstract

Understanding the behaviour of light propagation in biological materials is essential for biomedical engineering and applications, and even more so when dealing with incoming biomaterials. Many methods for determining optical parameters from biological media assume that scattered light is isotropically distributed over all angles. However, an angular dependence of light scattering may exist and affect the optical behaviour of biological media. The present work seeks to experimentally analyze the scattering anisotropy in different dental tissues (enamel and dentine) and their potential substitute biomaterials (hybrid dental-resin, nano-filled composite, and zirconia ceramic) and comparatively study them. Goniometric measurements were made for four wavelengths in the visible range, allowing a spectral characterization of the materials studied. Previously, for each material, measurements were made with two different sample thicknesses at the same wavelength, checking the behaviour of the angular scattering profile. The asymmetry of experimental phase functions was considered in the recovery of the scattering anisotropy factor. The results demonstrate that the thicker sample yielded a less forwarddirected scattering profile than did the thinner sample. The biomaterials analysed show angular scattering comparable to those of the tissues that they may replace. Comparisons can be made by virtue of the low uncertainties found.

Real-time evaluation of two light delivery systems for photodynamic disinfection of Candida albicans biofilm in curved root canals

“…According to Fernandez-Oliveras and co-workers, enamel and dentin present a different behavior upon irradiation with red light (632.8 nm) [35]. Also, the samples’ thickness directly interferes with light distribution since the thicker they are the more side-scattered light will be.…”

“…To reach the dental apex with the laser tip positioned at the pulp chamber entrance, a forward-directed scattering would be required. However, human dentin presents very strong side light-scattering properties since it consists of a complex inhomogeneous structure of collagen and hydroxyapatite allied to microtubules crossing a large portion of teeth in many different pathways [35]. …”

Simultaneous Measurement of Multiple Scattering Coefficient and Scattering Anisotropy Factor in Dental Demineralization

“…4(b)), which is because sound enamel is transparent in the 1300-1600 nm, the scattering angle is closer to the forward scattering. Fernandez-Oliveras et al, 16 who used visible light in goniometric measurement and demonstrated scattering anisotropy factor in enamel is around 0.92 at 632.8 nm. Darling et al 11 used angular resolved scattering measurements at 1310 nm coupled with Monte Carlo simulations to yield g = 0.96.…”

Optical properties of supra-nano spherical filled resin composites compared to nanofilled, nano-hybrid and micro-hybrid composites

“…These lower values of scattering, and therefore higher T, could be due to the shape of the filler of the supra-nano filled resin composites, opposite to the irregular filler shape found in the rest of the studied materials and to the fact that the refractive index of the filler is close to those of matrix resin of supra-nano resin composites 19,20) . A recent works 21,22) showed, in general terms, that the dental resin composites (nanocomposites and hybrid) and the human enamel exhibit a similar angular scattering behavior. Due to the similarities found between the spectral behavior of the supra-nano filled resin composites and the rest of the studied materials, it could be stated that this resin composite also presents a similar angular scattering behavior with the human enamel.…”