Inclusion Criteria:  Presence of angular periodontal intra-bony defects with clinical attachment loss ≥5 mm measured from CEJ to the deepest propping depth with no evidence of gingival recession optimal compliance as evidenced by no missed treatment appointment and high attitude towards oral hygiene  Exclusion Criteria:  Patients with relevant medical conditions that may affect periodontal regeneration and surgery smokers, pregnant or lactating women those whom periodontal surgery had previously been carried out on the selected site, and patients who taking any drug known to affect the number or function of platelets