Effect of Restoration Composition, Shade, and Thickness on the Cure of a Photoactivated Resin Cement

This study investigates the effect of selected properties of a restorative material (type, shade, and thickness) on the cure of a photoactivated resin cement. Disks of ceramic and resin‐based restorative materials of two extreme shades were made to provide thicknesses of 0.5 to 3.0 mm in 0.5‐mm intervals. Light transmission was measured through various thicknesses and shades of each restorative material type. The effect of light transmission, as influenced by restorative material type, shade, and thickness on resin cement cure was also determined. Thickness and shade of restorative material had the greatest influence on light transmission. For simulated restoration thicknesses 1.5 mm and greater, Dicor (Dentsply International Inc, York, PA) had greater transmission of light than the other materials, regardless of shade. At equal restorative material thicknesses, light transmission was similar for identical shades of the other three materials. Restoration shade and thickness also had the greatest influence on resin cement cure. Material type, although significant, had only a minor influence. At thicknesses of 1 to 2 mm, Dicor consistently yielded greater resin cement cure values than any other material tested. When considering the ability of restorative materials to transmit light for curing of photo‐activated resin cements, the thickness of the restoration and its shade are much more influential than the choice of restorative material. Dicor provides greater light transmission that results in the ability to photobond restorations of greater thicknesses than the other materials. For restorations greater than 1 mm in thickness, a dual cure or chemical cure resin cement should be used to provide maximal cement properties.