Porcelain fracture of metal-ceramic tooth-supported and implant-supported restorations: A review

Metal-ceramic restorations are widely used in den-tistry with a high degree of general success. However, fracture of these restorations does occur and usually frustrates both the dentist and the patient. Objective: This literature review discusses the factors that may lead to the fracture of these restorations whether they are tooth-supported or implant-supported with the aim of making dentists and technicians aware of these factors to avoid them. Factors reviewed include: tech- nical factors, dentist-related factors, inherent mate- rial properties, direction, magnitude and frequency of applied loads, environmental factors, screw-retained implant-supported restorations, and posterior canti- levered prostheses. Material and Methods: A net- based search in “Pubmed” was performed and com- bined with a manual search. The search was limited to articles written in English. Conclusions: the pub- lished literature revealed that the factors predispos- ing to fracture of metal-ceramic restorations may be related to the technician, dentist, patient, environ- ment, design of the restoration, or to inherent struc- ture of ceramics and others. However, if the dentist and technician understand these factors and respect the physical characteristics of the materials, most of those are avoidable.