[Black or white--Which choice for the molars? Part 2. Which does one choose for the restoration of posterior teeth: amalgam or composite?].

Abstract

The two direct dental restorative materials most commonly used today are silver-mercury amalgam and resin-based composite. The survival of dental amalgam restorations is twice as high than for composite fillings: polymerisation shrinkage, deficient marginal adaptation, higher wear rates, defective contact points leading to food impaction, insufficiently converted composite at the bottom of the cavity are problems that cannot be underestimated when using resin-composite. This does not imply that there is no weakness for amalgam: the need for retentive cavities at the cost of healthy tooth substance, weakening of the tooth's strength by cutting through the tooth crown's ridges, the risk of fracture of remaining tooth substance (mostly buccal and lingual surfaces) as the result of the cavity design, and the lack of adhesion between amalgam and tooth substance. Retaining a tooth's strength by the replacement of amalgam by resin-composites is not always the correct solution. In this respect, it can be questioned whether it is not appropriate to repair failing (extensive) amalgam restorations as to replace them with resin-composites. Research in this respect has demonstrated that dentists still are not convinced of this treatment option. Restoring a tooth in its original build-up or structure and function within the oral cavity is the basis of the biomimetic principle: the use of composite appears to be more obvious than restoring with amalgam. In the present survey pro's and con's of amalgams and resin-composites for the restoration of posterior teeth are weighted. The conclusion demonstrates that there is still a place for dental amalgam in modern restorative dentistry when plastic filling materials are used for the direct tooth repair or restoration.