Evaluation of Nano-crystalline Hydroxyapatite Silica Gel in Management of Periodontal Intrabony Defects

Inclusion Criteria: * Severe chronic periodontitis patients. * having at least one site with pocket depth ≥ 6 mm and clinical attachment level ≥ 5 mm, with radiographic evidence of bone loss as detected in periapical radiographs. Exclusion Criteria: * Pregnant women * Subjects had \<22 permanent teeth * Having any given systemic disease * Taking any type of medication and/or antibiotic therapy during the 3 months before the study * Received periodontal treatment within the past 12 months Current or former smokers