[Slip casting: design and processing].

Abstract

With the "In-Ceram" system ceramic constructions are made without any metallic support. The cosmetic ceramic (Vitadur N) is reinforced by an aluminous oxide framework made with a bio-ceramic containing 85% aluminium. The nature of this bio-ceramic and its use provide the originality of this procedure. In order to make this framework, a replica in special porous plaster is made based on the working model. This replica is plunged into a "barbotine" (aluminous oxide grains in suspension in water) which is deposited on the surface. After modeling this paste with a brush, the totality is dehydrated and brought to 1, 100 degrees C for 2 h without. This still fragile calcination is infiltrated by coloured glass. This second thermal treatment is carried out, after dehydration, at 1,080 degrees for 2 to 4 h, still vacuum. The second heating allows the calcination to become coloured and fill in the porosities. The conventional feldspar ceramic is then placed onto this very resistant (more than 580 MPa flexural strength) and exceptionally well adapted framework. This procedure is remarkable regarding the marginal adaptation, the quality of the aesthetic result, its biocompatibility and its ease in positioning. Moreover, the minimal thickness of the aluminium coping is 4/10 mm on the lingual and 3/10 mm for other sides, which therefore do not require any more laboratory work than what is required for making a ceramo-metallic crown. Clinical follow-up over four years allows it to be stated that the mechanical and aesthetic qualities of the procedure permit the making of: single anterior and posterior units which can be made splinted; anterior maxillary small bridges (3 or 4 units) under normal occlusal conditions; posterior small bridges, under favourable occlusal conditions.