Inclusion Criteria:  • patients having asymptomatic chronic apical periodontitis of size 4-5 according to periapical index scoring system  Exclusion Criteria:  patients who suffer from diabetes, osteoporosis, cancer, autoimmue disease patients who are in immune suppressed state patients receiving steroid, bisphosphonate, denosumab or antiangiogenic therapy alcoholism smoking patients having had antibiotic therapy in the past 4 weeks before starting treatment teeth with furcation involvement teeth with deeper than 4 mm probing depth or the same on neighboring teeth patients intending to undergo prosthodontic or orthodontic treatment within four years