Successful management of mandibular incisors with pulp canal obliteration using guided endodontics is described, for the first time in Iran. A 58-year-old man was referred for root canal treatment of teeth #24, #25 and #26. Upon radiographic examination, partial obliteration of the root canal system was detected. Cone-beam computed tomography (CBCT) was requested to enhance the diagnosis and detection of root canals. Next, a 3-dimensional (3D) guide was designed and printed to aid in localization and access to the root canal system with minimal destruction of the tooth structure. With the use of a targeted 3D guide, a conservative access cavity was prepared to avoid unnecessary removal of tooth structure. The teeth were successfully treated endodontically. Obtained results revealed that the technique can be effective and predictable for the management of calcified canals.