Evaluation of Platelet-rich Fibrin for Revascularization of Im-mature Permanent Teeth Versus Standard Apexification: a 12-month Clinical Follow-up Study

This study is an extension of a previous study [12], encompassing a 12-month fol-low-up period. The protocol for this study received approval from the ethical committee of the Faculty of Dentistry at Mansoura University (11111218) as a randomized con-trolled-clinical trial with a 1:1 allocation ratio for groups and subgroups. The sample size for this study was calculated based on Nagy et al.'s study [13], which determined a re-quired sample size of 28 teeth.

Inclusion and diagnostic criteria:

A total of 28 children, including both boys and girls, were recruited through daily pa-tient screenings in the Clinics of Pediatric Dentistry and dental public health department, Faculty of Dentistry at Mansoura University, following specific inclusion and diagnostic criteria:

• Patients were free of chronic systemic diseases.
• Clinically, a negative response to electric pulp sensibility testing confirmed the pres-ence of immature necrotic permanent teeth.
• Teeth were categorized as uncontaminated if, during the examination, there were no signs of pain, no tenderness during apical percussion, no tenderness of adjacent soft tissues, and no history of open sinus, fistula or swelling.
• Radiographically, teeth were with roots exhibiting thin dentin walls and open apical foramina larger than 1 mm, along with apical periodontitis (considered as contami-nated) or without apical periodontitis (considered as uncontaminated).

Patients' allocation: