This application claims the priority of Japanese Patent Application No.5-62294(62294/1993) filed Mar. 23, 1993 and No. 5-245715(245715/1993) filed Sep. 30, 1993, which are incorporated herein by reference.
In a facing crown for an artificial front tooth, a tooth color hard resin is formed and bonded on a facing portion of a metal frame so as to get a natural appearance. But a bonding force between the hard resin and the metal frame is far from perfect. In order that the hard resin may be bonded firmly on the facing portion of the metal frame, a rugged outer surface is formed on the facing portion of the metal frame by use of retention beads, and then the rugged surface is plated with tin. By utilizing the retention beads, the surface area of the facing portion can be enlarged. And by tinning, the bonding strength of the formed material can be improved.
In spite of the combination of the retention beads and the tinning, however, the bonding strength between the hard resin and the facing portion of the metal frame is not sufficient. According to circumstances, there is a possibility that the formed material made of hard resin will peel off. In order to improve the strength of the bond between of the hard resin and the metal frame, a bonding strength accelerator such as a 4-methacryloxyethyl trimellitate anhydride will be applied before forming the hard resin on the facing portion of the metal frame. But in spite of using the bonding strength accelerator, the strength of bonding between the hard resin and the facing surface of the metal frame is not satisfactory.
This invention has been originated for overcoming the above difficulties. culties. A purpose of this invention is to provide a surface treatment material for a metallic base of an artificial tooth and a surface treatment process using such surface treatment material with high bonding strength between the facing portion of the metallic base and a hard resin formed on the metallic base.