Shinichi Ukon

Studies on photopolymerized crown and bridge resin. Part 1. Physical properties of Dentacolor.

Light activated composite resin, Dentacolor, was examined on chemical composition, polymerization characteristics and bonding to a metal and adhesive resin cement in order to confirm the dental application of it. For bonding, the surface of metal, Au-Ag-Pd alloy, was treated as follows; a) retention beads added, b) retention beads+alumina sand blasting+tin electroplated+adhesive resin cement (Panavia EX), c) alumina sand blasting+tin electroplated+adhe sive resin cement.The results were summarized as follows;1) Dentacolor consists of 31 wt% of urethane dimethacrylate with a small amount of other methacrylate (unknown) and 69 wt% of composite filler (inorganic phase 47 wt%).2) The surface hardness of the cured product of Dentacolor was little affected by a position of a specimen in a photo-irradiation apparatus (Dentacolor XS) and a shade of Dentacolor, however, conversion of polymerization, which was presumed by its hardness of a vertical plane, was relatively high in the center of a flask.3) Compared with heat cured composite resin (Isosit), the surface hardness, wear resistance and solubility in water of Dentacolor were nearly equal, but the bending strength and water sorption were slightly lower than those of Isosit.4) The bonding strength of Dentacolor when another layer was put on the surface of its cured product was comparatively high (170 kg/cm2) and its value was little affected by the irradiation time to the first layer.5) The bonding strength of Dentacolor to the metal was increased with the surface treatment of the metal except for the method a)(170-180 kg/cm2).6) After thermal cycling, a good improvement of marginal sealing was shown by the surface treatment of the metal except for the method a)