Document Type : Original Article
Endodontics Department, Faculty of Dentistry, Ahram Canadian University, Giza, Egypt.
Restorative Dentistry Department, Faculty of Dentistry, Ahram Canadian University, Giza Egypt
Prosthetic Dentistry Department, Faculty of Dentistry, King Salman International University, El Tur, South Sinai, Egypt.
Background: Endodontically treated teeth are subjected to discoloration which must be treated for aesthetic purposes without weakening of tooth structure. Methods: Intra-coronal bleaching using different bleaching agents was tested for affecting the fracture resistance of teeth in three different groups, group 1(n=17) treated with sodium perborate, group 2 (n=17) treated with spirulina extract using photodynamic theory and group 3 (n=17) control group without bleaching. Fracture resistance of single rooted extracted premolar teeth were tested using universal testing machine under a compressive load of 135 degrees on the palatal aspect of the tooth until fracture. Results: Statistical analysis revealed no significant difference between bleaching protocols on fracture resistance of endodontically treated teeth, but they were significantly lower than the nonbleached control group. Conclusions: Bleaching of endodontically treated may compromise the fracture toughness and structural integrity of dentine after root canal treatment with both the conventional bleaching protocol and the photodynamic theory bleaching.