title: Preparation modifications for damaged vital posterior teeth.
abstract: The preservation of a severely damaged tooth with a cast restoration requires that the preparation be modified to make use of remaining tooth structure. Preexisting preparation features, such as boxes and isthmuses, and new ones, such as boxes, grooves, and pin holes, are employed to provide adequate retention and resistance. When destruction of coronal tooth structure exceeds one-half of the clinical crown, a pin-retained amalgam or composite resin core should be used to build up the tooth to receive a cast restoration.
mesh_terms: D003442:Crowns; D003723:Dental Amalgam; D003737:Dental Cavity Preparation / Q000379:methods*; D003772:Dental Pins; D003793:Dental Restoration, Permanent / Q000379:methods; D003779:Denture Design; D006801:Humans; D007284:Inlays; D014070:Tooth / Q000473:pathology; D014076:Tooth Diseases / Q000145:classification; D014082:Tooth Fractures / Q000628:therapy
chemical_list: D003723:Dental Amalgam