CURING DEPTH OF 4 COMPOSITE VENEERING MATERIALS POLYMERIZED WITH DIFFERENT LABORATORY PHOTO-CURING UNITS

Post-curing properties of composite materials are influenced by the ty pe of base monomer, activation system, filler content, and also by the type of light source employed. This study examined curing depth of fo ur composite veneering materials polymerized by means of two different high-intensity photo-curing units for the purpose of evaluating the c uring performance of the combinations of composite material and photoc uring unit. Two microfilled and two hybrid composite materials designe d for prosthetic veneer were assessed. The composite materials were cu red using two photo-curing units, one with a xenon light source and on e with two metal halide light sources, and exposure periods varied fro m 20 to 90 s. Curing depth of the materials was determined with a scra ping technique described by the International Organization for Standar dization (ISO 4049). Three-factor analysis of variance revealed that t he depth of cure was influenced by the type of composite material as w ell as by the photo-curing unit, and also by the exposure period (P = 0.0001). A microfilled composite material (Dentacolor) demonstrated th e greatest depth of cure (4.69 mm) after 90 s irradiation with a metal halide unit (Hyper LII). Of the two photo-curing units, the metal hal ide curing unit consistently exhibited greater depth of cure than the xenon curing unit (Dentacolor XS). Longer exposure increased the depth of cure for all combinations.