Failure of Guided Endodontic Access in a Severely Obliterated Root Canal: A Case Report of Drill Deviation.

Pulp canal obliteration (PCO) increases the risk of procedural errors during canal localization. Guided endodontics improves access accuracy, but its success depends on precise guide design, proper drill-sleeve alignment, and material stability. When these factors are compromised, deviations and unsuccessful canal location may occur. The present clinical case reports the management of a severely obliterated root canal in a maxillary lateral incisor in which static-guided endodontic failed to achieve canal localization, emphasizing the technical limitations and the successful conventional approach. A 69-year-old female patient presented with a maxillary lateral incisor exhibiting severe PCO. Cone-beam computed tomography (CBCT) confirmed obliteration of the cervical and middle thirds of the root canal. Despite careful planning and the use of a static endodontic guide, canal localization failed after repeated drill deviations toward the palatal aspect. Investigation revealed palatal wear of the resin template adjacent to the metallic sleeve, and the mismatch between the drill's active length and the guide sleeve's dimensions may have contributed to the observed deviation. The canal was successfully localized under operating-microscope magnification using ultrasonic tips, guided by anatomical information obtained from postoperative CBCT imaging. Cleaning, shaping, and obturation were completed without complications. After 3 years, the patient remains asymptomatic, with radiographic signs of satisfactory healing. This case reinforces that guided endodontics-although valuable-requires meticulous planning, precise drill-sleeve compatibility, and strict guide validation. Clinicians must remain proficient in conventional techniques for cases in which guided access fails.