Inclusion Criteria:  The patient will be in range of 20-45 years of age at the time of treatment, having periapical lesions starting from 5mm or more in diameter related to failed endodontically treated single canaled teeth.  Exclusion Criteria:  Any systemic debilitating disease such as:  Diabetes mellitus, renal disease, Liver disease or liver failure, Rheumatoid arthritis, Neoplastic disease or its treatment, chronic corticosteroid therapy, chronic hepatitis B or C , History of hepatitis A, pregnant females.