| 摘要 |
This invention relates to biomechanical devices comprising a liquid sinterable metallic alloy, characterized by a multi-phase, composite microstructure of isolated spherical grains approximately 50 microns in diameter distributed in an essentially nonporous matrix. The dental prosthetic divices include full-cast crowns, copings, pontics, inlays, onlays, and bridges. Other devices include reconstructive and orthopedic pieces. The ceramic portion of an alloy-ceramic assembly for the dental prosthetic device comprises the steps of: (a) forming an impression of the prepared dental surface; (b) mixing a siliceous abutment die material having a thermal expansion between room temperature and 600 DEG C, greater than that of the alloy of step (f) between room temperature and 600 DEG C that is from about 0.008 mm/mm to 0.015 mm/mm and a physical expansion between zero and about 0.03 mm/mm; (c) filling the impression with the abutment die material to form a die preform; (d) separating the preform from the impression; (e) firing the abutment die material at a temperature below 1500 DEG C to form a solid die having a replica of the surface; (f) covering the replica surface with a powdered metal alloy having an expansion coefficient between room temperature and 600 DEG C between 0.004 mm/mm and 0.015 mm/mm; (g) firing the alloy/replica composite under vacuum at a temperature between 900 DEG C and 1400 DEG C to form a coping of the single crown by sintering. Whereby the separation between the die and the alloy coping is from about 2 to about 25 microns. |
