Direct composite resin fillings versus amalgam fillings for permanent or adult posterior teeth

Low-certainty evidence suggests that composite resin restorations may have almost double the failure rate of amalgam restorations. The risk of restoration fracture does not seem to be higher with composite resin restorations, but there is a much higher risk of developing secondary caries. Very low-certainty evidence suggests that there may be no clinically important differences in the safety profile of amalgam compared with composite resin dental restorations. This review supports the utility of amalgam restorations, and the results may be particularly useful in parts of the world where amalgam is still the material of choice to restore posterior teeth with proximal caries. Of note, however, is that composite resin materials have undergone important improvements in the years since the trials informing the primary analyses for this review were conducted. The global phase-down of dental amalgam via the Minamata Convention on Mercury is an important consideration when deciding between amalgam and composite resin dental materials. The choice of which dental material to use will depend on shared decision-making between dental providers and patients in the clinic setting, and local directives and protocols.