Processing and bonding of dental ceramics

This chapter gives readers a concise introduction to ceramic dental biomaterials, draws attention to their surface pretreatment and to silane primers used before cementation, and discusses several findings based on experimental laboratory studies. Chemical aspects related to ceramic materials, their pretreatment (conditioning) and their cementation with resin cements are discussed. Ceramics (porcelains) form a very popular and safe group of restorative materials in contemporary dentistry because of their aesthetics and high biocompatibility and they are discussed elsewhere in this book in detail. Ceramics used in dentistry are mostly based on silicon, Si, a metalloid element that is predominantly found in the form of silica and various silicate minerals in the Earth's crust. No contraindications have been reported for ceramics. Ceramic materials have three major indications: (i) ceramic-metal crowns and fixed partial dentures, (ii) all-ceramic restorations consisting of short-span anterior bridges, onlays, inlays, crowns and veneers (laminates), and (iii) ceramic denture teeth. The chemistry of zirconia, a contemporary dental material of choice, is also discussed. For durable cementation, it is mandatory to acid etch enamel and dentin with ortho-phosphoric acid, H3PO4. On the other hand, the ceramic (porcelain) surface need to be etched with hydrofluoric acid, HF, followed by silanization. Silanes are key primer monomers owing to their special, unique chemistry and are therefore discussed in detail. Some other acidic agents used in dentistry are introduced. Resin zirconia bonding concepts and related laboratory studies finalize this chapter.