A Review of Amalgam and Composite Longevity of Posterior Restorations

Failure of dental restorations is a major concern in dental practice and its replacement constitutes the majority of the operative work. The purpose of this study is to review the longevity of Class I and II amalgam and direct composite restorations in posterior permanent teeth, and to discuss possible reasons for clinical failure. On average, longevity of resin composite restorations in posterior teeth is two to three times lower than amalgam restorations. The resin composite is an appropriate material to restore small Class I and Class II lesions, with margins located in enamel, on patients with low caries risk and, when complete field isolation can be achieved. The use of amalgam is preferable to the use of composite in large and complex restorations, with margins located in dentine or cement, where isolation is deficient. Durability of dental restorations is dependent upon many different factors, such as: operator skills, materials used, technique used, patient compliance and oral environment. The main reasons for restorations failure were secondary caries, restoration fracture, tooth fracture and marginal defects.