Industrial photochemistry-VI. Light distribution in photopolymerizable composite materials and heterogeneities observed in light sources used for the photoreaction

The use of photosensitive initiators of the polymerization of composite materials used in restorative dentistry has become widespread. Experimental and theoretical studies of hardening mechanisms as a function of chemical reactions leading to reticulation and of the light dispersion due to mineral fillers have been performed. Experimental profiles derived from our study deviate significantly from the classical Beer-Lambert absorption law. They demonstrated the difficulty of obtaining an homogeneous hardness of this material in the cured tooth cavity. At the same time, measurements of the distribution of light intensity at the irradiation surface of commercial sources have been performed. Observed heterogeneities can be explained using a computer assisted simulation taking into account the geometrical characteristics of optical fibers. This effect is reduced by the diffusion of light in the reaction vessel. © 1984.SCOPUS: ar.j