FRACTURE-RESISTANCE OF ENDODONTICALLY-TREATED PREMOLARS ADHESIVELY RESTORED

Purpose: To investigate the cusp fracture resistance of endodontically treated teeth, adhesively restored with various materials. Materials and Methods: MOD preparations and endodontic treatment was carried out on extracted sound maxillary premolars. The cavities were restored wi th the amalgam Valiant in combination with Superbond or Panavia bondin g, the resin composites Z100, Herculite XRV or Clearfil RP with their respective bonding systems, Z100 in combination with the glass ionomer s Ketac Fil, Fuji II and Vitremer, and Tetric in combination with Comp oglass. Fracture resistance was measured by axial loading in an Instro n testing machine. Results: One of the restorative methods, resin comp osites in combination with dentin bonding systems in beveled MOD prepa rations rendered the tooth a cusp fracture resistance which did not di ffer significantly from that of sound natural teeth. Two other restora tive methods, bonded amalgam and a sandwich of glass ionomer cement /r esin composite in beveled preparations were significantly weaker in re sisting cusp fracture than sound natural teeth, but still significantl y stronger than the unrestored tooth with a MOD preparation. It was st atistically apparent that several adhesive restorative systems could s atisfactorily be used to restore teeth after endodontic therapy.