Porcelain-fused restoration

Progressive dental reconstructions within the life-time of a patient, and in particular the use of different alloys for total or partial dentures, for dental fillings, for porcelain-fused restorations, and transcutaneous implants, generate unavoidable oral polymetallism. Indeed, two alloys of different composition have different electric potentials and inevitably induce corrosion and subsequently the release of metal ions into the human organism (Bundy 1994 Homez et al. 2000). 

In this section, the effects of chemical strengthening using ion exchange by paste method on the hardness and fracture toughness of dental porcelains with different microstmctures are shown. Table 1 shows descriptions of five porcelain powders used in this study, two recommended to be used as veneering materials for alumina cores (V and Ob) and three recommended for porcelain fused-to-metal restorations (C, D, and B), containing wide variation of leucite fraction (0 to 22 vol%). 

J. B. Quinn, G. D. Quinn, V. Sundar, Fracture Toughness of Veneering Ceramics for Porcelain Fused to Metal (PFM) and Zlrconia Dental Restorative Material, J. Res. NIST, 115... 

Gold alloys for porcelain-fused-to-metal dental restorations, R. German, Gold Bull, 1980, 13, 57. 

Platinum has many uses in dentistry. Pure platinum foil serves as the matrix in the constmction of fused-porcelain restorations. Platinum foil may be laminated with gold foil for cold-welded foil restorations. Platinum wire has found use as retention posts and pins in crown and bridge restorations. Heating elements and thermocouples in high-fusing porcelain furnaces are usually made of platinum or its alloys (see Platinum-GROUP metals). 

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