Eskander M E, Jabbar F A
Crown and Bridge Department, Faculty of Oral and Dental Medicine, Cairo University.
Egypt Dent J. 1993 Jul;39(3):453-6.
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.
陶瓷是牙科领域使用的最古老材料之一。它具有色泽再现完美、耐化学腐蚀和耐磨以及与口腔组织生物相容性好等优点。牙科陶瓷唯一的缺点是易发生脆性断裂。烤瓷冠外表面形成的微小裂纹是断裂的原因。这些裂纹是由于陶瓷冷却过程中瓷的低导热性而形成的。瓷冠内外表面发生不同的尺寸变化从而产生裂纹。瓷内表面的拉应力导致裂纹扩展和断裂。
