| 摘要 |
1,271,157. Artificial teeth. CERAMCO INDUSTRIAL PRODUCTS CORP. 28 April, 1969, No. 21616/69. Heading A5R. [Also in Divisions C3 and C7] Dental prostheses are formed from a putty comprising 2-25 micron metal powder and a binder comprising one of ammonium caseinate, ammonium stearate, pectin, hexamine, ethyl cellulose, anthracene, triacetyl starch, dulcin, carbazole and tetraphenyl ethylene and one of propylene glycol, water, eugenol, light paraffin oil, butyl acetate, butyl benzoate, diacetone alcohol and dibutyl phthalate, the putty being formed into the required shape e.g. by carving over a die and then sintered. In the formation of a coping for a dental crown the putty of gold or a gold alloy is applied to a die 14 in the shape of the tooth (Figure 2) and shaped to thickness by carving with a spatula. The die is a ceramic and is coated with mica in nitrocellulose to ease the stripping of the moulding. The assembly is prefired at 800‹-1200‹F, sintered at 1860‹F and then the sintered moulding is released from the die. To correct for shrinkage, a collar of the putty may be applied to the base of the die 14, the sintered moulding replaced on the die and embedded in the putty collar and then resintered. Au, Pt and RL powders may be mixed with silver resinate and a binder, the resinate decomposing during sintering to form Ag. Alternatively silver resinate may be applied to the sintered moulding which is then refired. An alloy of Au-Pt-Pd-Ag with or without 2-5% Si or Al may be used and liquid phase sintering may be applied to the following alloys. Ti-Ni 4:1 ratio Au-Pd-Pt-Ag-Si 80:5:5:5:8 ratio Fe-Ni-Bi-Sn 40:50:6:4 ratio In-Ni 3:7 ratio Fe-Cr-In-Sn 80:20:3:3 ratio Ag-Au-Si 45:50:8 ratio Ag-Au-Al 50:45:8 ratio The metal powders may be replaced by the oxides, hydroxides or organic metallic compounds which are reduced to metal on sintering. |
