CURING DEPTH OF A COMPOSITE VENEERING MATERIAL POLYMERIZED WITH 7 DIFFERENT LABORATORY PHOTO-CURING UNITS

Properties of laboratory-cured composite materials are affected by the type of activation system as well as by the photo-curing unit light s ource. This study examined curing depth of a composite veneering mater ial polymerized by means of various photo-curing units with the aim of evaluating the curing performance of the light sources. A microfilled composite material designed for prosthetic veneer was cured with seve n photo-curing units. The light sources of the units were halogen/fluo rescent, xenon, metal halide, fluorescent, halogen, halogen and mercur y lamps. Exposure periods were 20, 30, 60 and 90 s. The curing depth o f the material was determined using the method described by the Intern ational Organization for Standardization (ISO 4049). Two-factor analys is of variance revealed that the depth of cure was influenced both by the type of curing unit and by the exposure period (P = 0.0001). Among the seven photo-curing units, a metal halide curing unit consistently exhibited the greatest depth of cure. For all units, longer exposure increased the depth of cure.