The application of ceramics in oral restorations has a history of about 100 years, the earliest use of all-ceramic restorations, due to the poor mechanical strength has not been widely used. 1950s appeared in the porcelain fused to metal technology, the strength of the metal substrate structure and the aesthetic properties of the porcelain combined organically, greatly improving the fracture strength of porcelain crowns, this technology has been widely used in the production of dental restorations This technology is now widely used in the production of oral restorations. The more accurate name for “porcelain teeth” should be porcelain fused to attached full crowns, this technology first needs to be restored teeth for standardized cutting and grinding and take accurate impressions, reproducing an accurate working model. The working model is used to complete the metal crown by metal casting technique, then the low melting point porcelain powder is fused to the metal crown layer by layer through a special process, and finally the shape and color are modified to complete the final porcelain tooth restoration. Porcelain restorations do not fully restore the aesthetics and function of the restored teeth. Especially after the restoration of anterior teeth gingival margin discoloration problem, due to the restoration of the base is metal, affecting the light transmission, and the translucent nature of the natural teeth can make part of the refracted light through the thin gingival margin, so some patients in the porcelain tooth restoration after the gingival margin dark phenomenon, in addition to the many patients on non-precious metal porcelain restorations often occur allergic reaction can also lead to gingival margin discoloration occurs. Functional recovery: due to the relatively high brittleness of porcelain materials, in the chewing process after restoration, if inadvertently biting into hard objects may cause the porcelain layer to fall off, and ultimately affect the restoration effect. All these factors have contributed to the development and application of new all-ceramic crowns with better aesthetic results and higher mechanical strength. All-ceramic crowns and enamel close to the transparency and refractive index, the appearance of the color and natural teeth are not far from each other, can achieve the best aesthetic effect, coupled with its good biocompatibility, and constantly improve the strength and toughness, has been increasingly favored.