Can porcelain-fused-to-metal (PFM) crowns develop dental caries?

Porcelain teeth can lead to tooth decay. If the margin of a porcelain-fused-to-metal (PFM) crown is excessively long, it may cause congestion of the surrounding oral soft tissues, resulting in gingival recession and exposure of the cervical region of the tooth. Food debris and soft plaque can damage teeth and promote dental caries. Due to microleakage at the interface between the porcelain crown and the abutment tooth, contaminants from food may infiltrate beneath the crown, facilitating bacterial proliferation in the oral cavity and ultimately causing decay of the abutment tooth. Prolonged use and sustained occlusal forces may damage the oral mucosa; meanwhile, accumulated soft plaque and dental biofilm around the gingiva generate substantial acidic metabolites, leading to demineralization of the abutment tooth. There is also a risk—albeit variable—of pulpitis and apical periodontitis.