Inclusion Criteria:  1. Age 16 years and older consenting to the surgical procedure as well as agreeing to preoperative and at least 1 follow-up CBCT evaluation after 12 months 2. Noncontributory medical history (American Society of Anesthesiologists class I and II) 3. Patients with a deep narrow pocket with probing depth >6 mm confined to buccal aspect of the root, 4. Negative response to vitality tests, 5. Radiographic evidence of radiolucency, 6. Failed previous root canal treatment and retreatment at least 1 year previously, 7. Previous surgery with unresolved bony lesion, 8. Recurrent episodes of purulent discharge, and 9. Adequate final restoration with no clinical evidence of coronal leakage.  Exclusion Criteria:  - 1. Patients with medical history with American Society of Anesthesiologists class III to V or Any systemic disease contraindicating oral surgical procedures, potentially affecting the healing process.  2. Chronic generalized periodontitis, 3. Evidence of root fracture, 4. resorptive processes involving more than apical third of the root