Missed anatomy: frequency and clinical impact

The impact of missed anatomy on the outcome of endodontic treatment is difficult to assess, and the literature on this subject is limited; a promising approach for future investigation may be a comparison of the number of canals found in failed treatment cases and after re-treatment. The clinical impact of missed anatomy can be clearly demonstrated with a large number of re-treatment case reports available in the literature; in the majority of these cases, failure of endodontic therapy is associated with untreated canal space. Localization and treatment of this missed anatomy typically leads to complete clinical and radiographic healing.