Endodontic retreatment.

Endodontic failure is a difficult diagnosis to confirm. Various other pathologic entities that must be ruled out by radiographs and tests have been discussed. Because of significant and, as yet, unresolved problems with surgical endodontic treatment, conservative retreatment should be given priority in treatment planning. Specialized techniques that can be used successfully to remove endodontic posts, gutta-percha silver cones, Thermafil, and paste filling materials from root canals have been discussed as well.