This study will compare the effect of guided tissue regeneration using a mixture of autograft and PRF covered with a collagen membrane as compared to the membrane alone in the healing of apicomarginal defects. Healing of the lesions will be compared 2 dimensionaly and 3 dimensionaly using CBCT.

Patients with apicomarginal defects as per the inclusion criteria will be randomly divided into two groups -in test group 1 -the defects will be filled with a mixture of autograft(which will be obtained from the surrounding buccal cortical plate by using a trephine bur) and prf(will be prepared by Choukron's method) and the defects and denuded root surface will be covered with a collagen membrane and in test group 2 -the defects will be filled with a blood clot and over that the collagen membrane will be placed. Radiographic and clinical healing will be assessed after 12 months, 2D healing will be assessed by Rud and Molven criteria and 3D healing will be assessed by Modified Penn 3D criteria.The clinical parameters recorded including periodontal pocket depth (PD), clinical attachment level (CAL) and gingival margin position (GMP) and will be measured on buccal aspect of the interproximal space and mid buccal aspect of the involved teeth using Williams 'O' periodontal probe.Routine examination procedure will be used to evaluate any evidence of signs and/or symptoms.. The criteria for a successful outcome included the absence of clinical signs and/or symptoms and radiographic evidence of complete or incomplete healing.

Inclusion Criteria:

• Patients with age 16 years to 55 years
• Periapical defects with periodontal communication.
• Apicomarginal defects with probing depth > 6mm on mid-buccal and interproximal surfaces

Exclusion criteria

• Presence of buccal bone on flap elevation.
• Fractured /perforated roots.
• smokers.
• pregnant females and lactating mothers

double