Perforations in the furcation region are one of the major complications leading to failure of endodontic treatment and causes significant impact on the long term prognosis of the tooth. It is estimated that furcation perforation is the second major cause of failure in endodontics. Biodentine is a calcium silicate-based bioactive material. It is a powder liquid system, powder composed of Tri-calcium silicate, Di-calcium silicate, Calcium carbonate and oxide, Iron oxide, Zirconium oxide. Liquid consist of Calcium chloride, Hydro soluble polymer. It is easy to handle owing to its ease of manipulation and a short setting time approximately 12 minutes, has high alkaline pH and is a biocompatible material makes it a favourable material for perforation repair, whereas cyanoacrylate has been shown to be an excellent tissue adhesive and hemostatic agent which is well tolerated by the tissues of the oral cavity, promotes healing of the tissues. Hence, this study would compare the microleakage of mineral trioxide aggregate and cyanoacrylate cement, in repairing furcal perforations using 2% methylene blue dye solution, conc. Nitric acid, ELISA plates for detecting the maximum dye leakage.