Objective To evaluate the effect of furcal perforation treated with iRoot BP.Methods Forty newly extracted human maxillary and mandibular molars were collected. Holes in diameter of 2 mm were prepared at the roof of the central pulp cavity of 36 samples with high speed round ball diamond in order to make perforated model, and then equally and randomly divided them into two groups. The other intact four samples were used as the negative controls. In the experimental groups, group A were repaired by iRoot BP, group B were repaired by mineral trioxide aggregate（MTA）. Three samples in each group were observed under scanning electron microscope（SEM）, and micro-leakage of others was tested by measuring the concentration of leaked glucose with the enzymatic glucose oxidase-peroxidase（GOD-POD） method.Results Microleakage of group B was higher than group A and had statistical difference（PConclusion For repairing furcal perforation, the effect of iRoot BP is better than that of MTA.
