Hands On

Posterior restorations in amalgam and composite resin

Background

Various materials have been used to create direct restorations in posterior teeth. Amalgam has been used for many years, but more recently composite resins have been used to meet the demand of patients for more esthetic restorations. Amalgam restorations offer high functional durability, but are viewed negatively because mercury is incorporated into the metal alloy and more dental preparation is required. The drawbacks to composite resins are sensitivity to manufacturing technique; contraction

Methods

An electronic search was conducted for applicable studies in the PubMed/MEDLINE, Cochrane Central Register of Controlled Trials, and Web of Science databases. Eight studies performed between 1992 and 2013 were included, all classified as offering high-quality evidence. Two were randomized clinical trials, five prospective cohort studies, and one a retrospective cohort study were analyzed.

Results

Compared to composite resin restorations, occlusal and occlusoproximal amalgam posterior restorations demonstrated greater clinical longevity. The amalgam alloys used had a high copper content, which provides better clinical performance. The mean rate of survival for the amalgam restorations was 92.8%, whereas that for composite resins was 86.2%. Mean follow-up was 55 months (range 12 to 120 months).

Failures were attributed most often to secondary caries and fractures of the teeth. Composite

Discussion

Longer functional life was achieved using amalgam restorations than with composite restorations. Secondary caries was more prevalent among the composite restorations but fractures occurred at similar rates between the two materials.