Advantages and Disadvantages of Resin Composites and Amalgam Restorations

Marcinkowski, Jenica, Flora Hakeem, Darleen Shaba, and Amanda Sternicki

Purpose: To compare the two dominant materials used for direct dental restorations – resin composites and amalgam.

Summary: In studies, composite restorations had greater failure rates than amalgam restorations. These studies state composites are frequently seven times more likely than amalgams to be replaced due to recurrent caries and seven times more likely to be repaired do to other reasons. The risk for fracture was equal in both composite and amalgam restorations. Amalgams are resistant to wear but are very brittle and chip easily on a fillings edge. Composites are Moderately resistant to wear and are not brittle. These significant findings support reports stating amalgam restorations of have greater longevity than resin-based composites.

 Resin composites are more expensive than amalgam restorations. Cost of Composites can range from $150-$200 per tooth and Amalgams range from $ 75-$145 per tooth.

In 1991, a survey done by ADA found 1,000 Americans believed health problems develop as a result of the mercury in dental amalgams; however, the National Institute of Health & Public Health Service has been unable to find any adverse effects. Several researchers have examined how much mercury is released into the body by relating the blood/urine content of Hg to the amount of dental amalgam restorations – no correlation could be found. In dental composites there have been concerns that the material could release components similar to estrogen. This could lead to health issues.  Resin-based dental restorative materials have been targeted as potential sources of xenoestrogens, specifically bisphenol A and bisphenol A dimethacrylate, which could contribute to overall estrogen load and result in deleterious side effects. A study was done to analyze twenty-eight different commercially available dental resins for the presence of BPA and/or BAD. It was found that composites in general do not represent a significant source of BPA or BAD exposure. Amalgam is well known to have poor esthetics due to its gray metallic appearance. Composites are much better esthetically pleasing. Composites can be bonded to tooth structures. This allows it to be used for several applications that would not be possible with amalgam.

A study was conducted to observe the amount of plaque and Streptococcus mutans in saliva and among composites and amalgams. It was found that Composites expressed more accumulation among all the studies compared to amalgam.

Conclusion: In comparing amalgam and composite restorations, amalgams last the longest and are least expensive. In addition, there is no evidence of biocompatibility issues from the mercury in amalgam. The areas where composites are better than amalgam are esthetics and the ability to bond to teeth.