The placement of bases beneath amalgam restorations: review of literature and recommendations for use.

On the basis of the literature, it can be concluded that there are no absolute rules regarding the placement of bases under amalgam restorations. The following recommendations are offered: A base should not be used unless its use is indicated clearly. When a base is indicated, it should be used with the minimum thickness necessary to achieve the desired result. Lost dentin should not be replaced with a base in an attempt to simulate an ideal preparation. A stronger base should not be placed over a weaker base, for strength. The entire base is only as strong as the weakest component. Covering the entire pulpal floor with a base should be avoided. Sound dentin surrounding the base should be left so that the amalgam restoration is supported by dentin as much as possible.