Abstract: The root canal system in the first premolars is varied, and the symmetry of three roots and three canals in maxillary and mandibular first premolars is extremely rare in female patients. In this paper, we review the cases of three or multiple root canals in the first premolars and report one case of symmetry three roots and three canals in the maxillary and mandibular first premolars, with aim to provide supplementary data for clinical diagnosis and treatment.

Key words: three root canals, cone-beam computed tomography, first premolar