Abstract: A sliding-contact type ceramics article having a high density portion for increasing the mechanical strength of its slide-contact portion with an associated article. A method for manufacturing such a sliding-contact type ceramics article which is characterized in that, at first a compact body having a configuration which is approximate to a final article is molded in such a manner that a slide-contact portion with an associated article is intensively compressed, and then the compact body is grinded to obtain a compact body of a final configuration.

Abstract: An improved investment casting process for producing dental restorations, particularly a dental crown, comprising the steps of fixing a wax pattern onto a truncated cone in a metallic ring having a lining of a cushioning material, pouring an investment material into the space around the wax pattern in the metallic ring, drying the resultant product, melting out the invested wax pattern, curing the resultant product at a temperature of 700.degree. to 950.degree. C for 20 to 150 minutes to give a mold, fixing the mold thus obtained to a centrifugal casting machine and casting a molten chromium-cobalt and/or nickel alloy in the mold maintained at a temperature of 100.degree. to 500.degree. C.