Porcelain is one of the oldest materials used in the dental field. It has the advantages of perfect shade reproduction, chemical and abrasion resistance and biologic compatibility to the oral tissue. The only drawback of dental compatibility to the oral tissue. The only drawback of dental porcelain is the occurrence of brittle fracture. Minute cracks formed on the outer surface of the porcelain crown are the cause of the fracture. These cracks are formed during cooling of the ceramic as a result of low thermal conductivity of the porcelain. Differential dimensional changes of the outside and the internal surface take place inducing the cracks. Tensile stresses on the internal surface of the porcelain lead to cracks propagation and fracture.