Immature permanent teeth with apical pathosis and pulp necrosis represents a therapeutic challenge. Necrotic pulps occur in instances of untreated carious lesions or trauma to the anterior teeth. The latter situations represent challenge in root canal debridement and filling and due to thin dentinal walls leading to increased risk of fracture (Cvek.,1992).
Insufficient data exists concerning the use of PRF as a scaffold in regenerative endodontic. Knowledge about the nature of regenerated cells remains unclear. Therefore, we conducted this study to compare between 2 different scaffolds; blood clot and Leukocyte-platelet-rich fibrin (L-PRF) concentrates. In addition, we performed histological evaluation in dogs in terms of presence of absences or inflammation, presence or absence of vital pulp tissue, presence or absence of new hard tissue and however the new cells are reparative or regenerated cells.