COLOR AND TRANSLUCENCY CHANGES DURING AND AFTER CURING OF AESTHETIC RESTORATIVE MATERIALS

Objectives, This study was conducted to evaluate various types of cont emporary resin composites and glass ionomer restorative materials for color differences that occur during light curing and after submersion in water. Additionally, translucency was evaluated through the use of a translucency parameter for each of these materials at these times. M ethods. A translucency parameter was calculated from observed colors o f 2 mm thick layers of light, medium and dark shades of popular restor ative materials on black and white backings. The colors of these mater ials were also calculated, based on Kubelka-Munk theory, for layers on a B2 shade backing. Repeated measures analyses of variance were used to identify statistically significant factors for color differences an d translucency parameters. Results. A statistically significant intera ction was found between the products, shades and time intervals or tim es studied for both color difference and translucency parameter. There is relatively high variability in both lightness and translucency cha nges among these popular products, with some products increasing and o thers decreasing in these parameters with curing and subsequent water submersion. Significance. Kubelka-Munk theory can be used to calculate the color of a layer of material on a backing other than those used t o determine the Kubelka-Munk coefficients, thereby increasing the effi ciency of research into the optical properties of esthetic restorative materials. The relatively large optical changes which occur as popula r esthetic restorative materials are cured and subsequently submersed in water indicate that these changes should be taken into account duri ng any initial clinical appearance match at placement of the unset mat erial.