Abstract: Objective: To investigate the branch canal anatomy of the maxillary first premolars of Chinese people with micro-CT. Methods:Sixty-three maxillary first premolars were scanned by micro-CT and root canals were visualized by three-dimentional reconstruction. Branch canals and apical delta were recorded. The incidence, distribution and exit opening direction of branch canals were analyzed. Results: Branch canals of 50 teeth were recorded. The incidence of the branch canals was 79.37%. A total of 124 branch canals were recorded, and 95.16% of branch canals were located at the apical third of the root. The direction of the apical foramen of 33.06% branch canals were found at mesial, and the direction of the apical foramen of 23.39% branch canals was at distal side of the root. Incidence of apical delta was 7.94%. Conclusion: The root canal system of maxillary first premolars was complicated, with a high incidence of branch canals. It is important to know the branch canal morphology so as to increase the success rate of root canal treatment.

Key words: Maxillary first premolars, Branch root canals, Micro-CT technique