Endondontic Retreatment

The major goals of root canal retreatment are to clear and shape the root canal system and seal it in 3 dimensions to prevent reinfection of the tooth. Lack of healing is attributed to persistent intra-radicular infection residing in previously un-instrumented canals, dentinal tubules, or in the complex irregularities of the root canal system. The extra-radicular causes of endodontic failures include periapical actinomycosis, a foreign body reaction caused by extruded endodontic materials, an accumulation of endogenous cholesterol crystals in the apical tissues, and an unresolved cystic lesion. Previously treated teeth with persistent periapical lesion might be preserved with non-surgical re-treatment or endodontic surgery, assuming the tooth is restorable, periodontally round, and the patient desires to retain the tooth. Post-treatment endodontic disease does not preclude saving the involved tooth. In fact, the vast majority of these teeth can be returned to healthy and long-term function by current retreatment procedures.