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The indications for posterior bonded porcelain restorations overlap those for direct and indirect posterior resin composite restorations, which have been described.
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These restorations are indicated when there is an overriding desire for esthetics and all margins can be placed on enamel.
Materials 1. Feldspathic porcelain 2. Hot pressed ceramics 3. Machinable ceramics for CAD/CAM system Feldspathic Porcelain Inlays and Onlays These porcelains are partially crystalline minerals (feldspar, silica, alumina) dispersed in a glass matrix. Porcelain restorations are made from finely ground ceramic powders that are mixed with distilled water or a special liquid, shaped into the desired form, then fired and fused together to form a translucent, material that looks like tooth structure. Currently, many ceramic inlays and onlays are fabricated in the dental laboratory by firing dental porcelains on refractory dies. The fabrication steps for fired ceramic inlays and onlays can be summarized as follows: 1. After tooth preparation, an impression is made and a "master" working cast is poured of die stone. 2. The die is duplicated and poured with a refractory investment capable of withstanding porcelain firing temperatures. The duplication method must result in the master die and the refractory die being accurately interchangeable. 3. Porcelain is added into the preparation area of the refractory die and fired in an oven. Multiple increments and firings are necessary to compensate for sintering shrinkage . 4. The ceramic restoration is recovered from the refractory die, cleaned of all investment, and seated on the master die and working cast for final adjustments and finishing. The major disadvantage of this technique is its technique sensitivity. Although some technicians can routinely fabricate these restorations with excellent marginal integrity, many dentists complain of problems with fit and strength. Inlays and onlays fabricated
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