| 摘要 |
The invention relates to dental constructions such as bridges, crowns and the like which utilize a novel dental alloy as a metal core and porcelain or other tooth simulating material bonded thereto. The dental alloys are composed primarily of nickel, and chromium and contain on a weight percent basis, about 65 to 80 per cent nickel, about 12.0 to 20.0 per cent chromium, and in addition about 3.5 to 5.0 per cent silicon, about 3.0 to 6.0 per cent molybdenum, and about 0.2 to 0.6 per cent boron. More preferably the alloys consist essentially of 71 to 74.3 per cent nickel, 17.5 to 19.5 per cent chromium, 3.9 to 4.5 per cent silicon, about 3.9 to 4.5 per cent molybdenum and 0.3 to 0.5 per cent boron. The alloys have excellent physical properties for dental applications having a fusion temperature with the range of about 2300 to 2450 DEG F (1260 DEG C to 1343 DEG C), a coefficient of expansion of from about 13.6 x 10<-><6> in/in/ DEG C (13.6 x 10<-><6> DEG C<-><1> to about 14.5 x 10<-><6> in/in/ DEG C (14.5 x 10<-><6> DEG C<-><1>), good corrosion resistance when compared with similarly cast gold or other commercial non-precious metal dental alloys and good oxidation resistance. They also have as cast, a tensile strength of at least 80,000 p.s.i., an elongation of about 2.0 to 5.0 per cent, a Rockwell B hardness within the range of about 90 to 100, and good bonding to porcelain. |
