Abstract
Successful endodontic treatment depends on a comprehensive understanding of root canal anatomy and its possible variations. Radix entomolaris (RE) is a rare anatomical variant characterized by the presence of a supernumerary distolingual root, most frequently found in mandibular first molars. This case report describes the clinical and radiographic identification of an RE in the mandibular first molar of a 42-year-old male patient presenting with symptomatic irreversible pulpitis. The additional root was identified during access cavity preparation, necessitating modification of the access outline to enable detection of all canal orifices. In this case, the RE exhibited no mesiodistal curvature and did not conform to established morphological classifications. Given the clinical challenges associated with such anatomical anomalies, heightened vigilance is essential to prevent iatrogenic complications and ensure treatment success. Early recognition and appropriate adaptation of endodontic procedures are critical for long-term tooth preservation and favorable outcomes.