The rebuilding of endodontic treated teeth is a common situation in general dental practice. The final (post-) core buildup, with or without a crown, should protect the restoration as well as the tooth against fracture, should prevent debonding of the restoration, should not permit leakage and should provide an acceptable esthetic result. Several factors influencing these properties are described. The (post-) core buildup in relation to the concept of minimally invasive dentistry is discussed. In conclusion, there is no unambiguous guideline for restoring endodontically treated teeth. Standardised in vitro and in vivo studies are needed.