What is the most common failure in constructing porcelain-to-metal restorations?

The most common failure in constructing porcelain-to-metal restorations is attributed to improper metal framework. This refers to how well the metal framework is designed and fabricated to support the porcelain overlay. A faulty metal framework can lead to numerous issues such as misfit, poor retention of the porcelain, and eventually catastrophic failure of the restoration.

The metal framework needs to be accurately shaped and properly adapted to the tooth structure to ensure that it can withstand the masticatory forces and the thermal expansions that occur during the heating and cooling phases of firing the porcelain. If the framework does not fit properly, it can create stress points that may lead to chipping, cracking, or the complete delamination of the porcelain layer from the metal base, leading to a restoration that is unable to function effectively in the patient’s mouth. This highlights the importance of precision in the initial construction of the metal framework in porcelain-to-metal restorations.