Determination of the etiology of the patient's chief complaint and a correct diagnosis are paramount prior to a recommendation of endodontic therapy. Reproduction of the patient's chief complaint is critical. If the chief complaint cannot be reproduced, consider consultation with or referral to an endodontist or orofacial pain specialist. The diagnostic terminology presented in this update provides for a more accurate description and communication of the health or pathological conditions of both pulpal and apical tissues. This information is summarized in Table I.