MECHANICAL TESTING OF A PHOTOCURED CHOPPED FIBER REINFORCED DENTAL COMPOSITE.

The objective was to validate strength improvements by incorporating chopped fiber into commercial particulate filled visible-light cured dental pastes. Photocurable resin preimpregnated 3-mm high purity quartz fibers were blended into two universal commercial composites, 3M Corp. Z100 and Kerr Corp. XRV at 35 wt% fiber. Four groups, consisting of the Z100 and XRV controls, along with Z100 and XRV both containing fibers, were prepared in a mold 2×2×25-mm then cured at equivalent irradiation intensities monitored by a Demetron Radiometer. Evaluation was accomplished on ten specimens from the four different categories according to ASTM Standard C 1161-94 configuration-A utilizing a fully-articulated four-point bend fixture and 20-mm span. Five samples out of each group were further assessed using a modified Izod Plastic Impact Tester per ASTM D 256-00. Both highly strengthened fiber reinforced composites attained a marginal error of uncertainty for statistical significance over the commercial controls (p=0.001 AVOVA posthoc Newman-Keuls) with maximum bending stress, flexural modulus, work of fracture and Izod impact toughness. From the results, it can be concluded that photocured chopped fiber reinforced composites will produce improvements over particulate filled compounds that can be considered breakthrough.