Perforations are mishaps that might occur during the course of endodontic treatment mainly due to iatrogenic factors. However, they might also occur due to extensive decay of dentinal structure.

A perforation creates a pathological passage between the root canal system and the periodontium and jeopardizes the success of the endodontic therapy. The damage caused by the perforation may eventually result in the extraction of the compromised tooth

Chitosan is the most abundant biopolymer on the earth derived from chitin. It shows a remarkable effective broad spectrum antibacterial action attributed to its cationic nature. It interacts with the -ve charged bacterial cell membranes, leading to leakage of the intracellular constituents and ultimately cell death due to increasing the membrane permeability. Also, chitosan possesses a variety of other biological properties as being biodegradable, biocompatible and has chelating abilities, making it an interesting alternative to modern root canal irrigants.

Inadequacy of the repair materials has been a contributing factor to the poor outcome of repair procedures. On the basis of the recent physical and biologic property studies of the relatively new introduced mineral trioxide aggregate, this material may be suitable for closing the communication between the pulp chamber and the underlying periodontal tissues. There are few reports on repair of furcal perforation with MTA in molar teeth.

Several studies have stated the ability of chitosan as a chelating agent that potentially enhance the dentin wettability. At the same time, chitosan nanoparticles showed the potential to stabilize dentine collagen by providing resistance to bacterial collagenase degradation.

The null hypothesis: there is no difference in pain and healing between the two irrigation protocols of old fural perforations prior to application of Bio C repair material.

Inclusion Criteria:

• Patients with old furcation perforation of mandibular molar.
• Size of perforation should be of average 1 to 2 mm.
• Period till treatment should be done within one month.
• Presence of polyp at the site of perforation is required in this study.

Exclusion Criteria:

• Teeth in need for post retained restoration.
• Immunocompromised patients.
• Pregnant women and smokers.
• Patients with a history of antibiotic or analgesics intake within the few days before the intervention and cases with previously initiated endodontic treatment.