The study examines the impact of advanced platelet-rich fibrin (A-PRF) on bone regeneration in apical surgery compared to standard methods. It highlights the effectiveness of ultrasound as a diagnostic tool for assessing periapical lesions. Eligible participants were adults with specific periapical lesions following root canal treatment failures. Exclusions included patients outside specific criteria, like those with advanced periodontal disease or undergoing orthodontic treatment. Participants were randomized into two groups: one receiving A-PRF to enhance bone regeneration and a control group without it. Both groups underwent apical surgery under magnification, with different postoperative protocols. The study involved radiological and ultrasonographic evaluations of lesion size and bone healing at baseline, 6 months, and 12 months, alongside blood analyses for Vitamin D and cholesterol level to assess their potential impact on healing.

Inclusion Criteria:

1. Adult patients with precisely defined periapical lesions related to maxillary or mandibular incisors and premolar teeth as a sequel to persistent endodontic infection
2. Patients after root canal treatment/retreatment
3. Patients with or without the sinus tract
4. Patients with root perforations
5. Patients with clinical cases deemed unsuitable for non-surgical endodontic intervention
6. Patients with traumatic lesions clearly indicated for endodontic apical surgery.

Exclusion Criteria:

1. Patients younger than 18 years
2. Patients with lesions unrelated to the root apical area
3. Patients in possession of vital teeth with radiolucency in the apical region
4. Pregnant patients
5. Patients with non-restorable teeth
6. Patients with advanced periodontal disease
7. Patients with uncontrolled systemic health conditions
8. Patients receiving bisphosphonate therapy
9. Patients receiving orthodontic treatment.