This study compared the Biodentine (BD) and MTA in repair of furcation perforation (FP) in a dog model in terms of inflammatory cell count and new hard tissue formation through histological and immunohistochemical evaluations. Ninety six teeth in six adult mongrel dogs were divided according to the time of repair into two groups (48 teeth/3 dogs each); immediate and delayed repair of the induced FP. Each group was divided into three subgroups (16 teeth each) according to the evaluation periods; 1, 2, and 3 months. Each subgroup was further subdivided into four subdivisions according to the material used; MTA (6 teeth), Biodentine (6 teeth), negative control (2 teeth) and positive control (2 teeth). In experimental and positive control samples, the teeth were instrumented and obturated then, a FP was performed. The perforations were sealed according to the groups and subdivisions. Histopathology and immunohistochemical analysis using Osteonectin antibodies were performed for assessment of the inflammatory cell count and new hard tissue formation. In all groups and subgroups, there were no significant differences between MTA and BD in the inflammatory cell count and new hard tissue formation (P>0.05). Biodentine can alternate the MTA as a FP repair material.