Novel hydroxyapatite-based dental composites.

Newly designed composite resins for dental applications have been studied. The matrix phases were based on 2,2 bis-4(2-hydroxy-3-methacryloyloxypropoxy)phenyl propane and a urethane dimethacrylate. Tetrahydrofurfuryl methacrylate was added as a diluent to both dimethacrylates in a proportion of 30 wt%. Heat-cured composite resins were obtained with filler weight fractions of 60% and 67%. After surface treating hydroxyapatite powder with a silane coupling agent, filler contents of 60%, 67% and 80% were employed. These materials were then evaluated for Young's modulus, flexural strength, diametral tensile strength and Vickers hardness. With the exception of Young's modulus, all mechanical properties of the tested materials were significantly improved when a silanized hydroxyapatite filler had been used.