Aim of this study is to evaluate the effect of i-PRF in the healing of through and through periapical lesion after periradicular surgery

Detailed patient examination will be carried out and those satisfying inclusion criteria will be enrolled in the study. Written informed consent will be obtained and patients will be randomly allocated to two groups. Entire surgical procedure will be carried out by single operator. After complete elevation of the flap, debridement (periradicular curettage -enucleation) of the bony lesion will be performed. 3 mm root-tip resection will be performed and root end cavity will be prepared using an ultrasonic diamond-coated retrotip. Root end filling will be done with mineral trioxide aggregate (MTA). In test group The i-PRF will be produced and incorporated with collagen will be used to fill into the defect. In the control group, no guided tissue regeneration technique will be used. Flap will be re-positioned and sutured using nonabsorbable 4-0 silk sutures.Sutures will be removed 4-7 days postoperatively.

Inclusion Criteria:

• Patients of age 16-55 years with a clinical & radiographic diagnosis of through and through periradicular lesion using CBCT
• Negative response to sensitivity tests with radiographic evidence of periapical radiolucency.
• Failed previous root canal treatment primary or secondary with purulent discharge and radiographic evidence of periapical pathology.
• The teeth must have adequate final restoration with no clinical evidence of coronal leakage.

Exclusion Criteria:

• Unrestorable tooth.
• Fractured / perforated tooth.
• Systemic diseases contraindicating surgical procedures or with potential to affect healing.
• Teeth with deep pockets.
• Patient requiring antibiotic premedication.
• Patients with history of antibiotic use in last 3 months.
• Smokers