Traditionally, immature permanent teeth with necrotic pulp and apical periodontitis are treated with apexification procedures using calcium hydroxide (CaOH2) or by performing an apical barrier with Mineral Trioxide Aggregate (MTA) prior to filling the root canal . The CaOH2 apexification procedure generally encompasses multiple visits and a long period of treatment time. Prolonged treatment with CaOH2 can break the bonds between collagen fibers and dentin hydroxyapatite crystals, which leads to microhardness reduction and increased fracture susceptibility. An apical barrier with MTA shortens treatment time. The treatment of apexification with CaOH2 or apical barrier of MTA is biocompatible and bioactive, however, a procedure of apexification in immature permanent teeth with necrotic pulp, has no potential to restore the vitality of the damaged tissue in the canal space and promote root maturation (thickening of root canal walls and / or apical closure). The European Endodontic Society (ESE) and the American Association of Endodontists (AAE) have issued position statements and clinical considerations for regenerative endodontics . Regenerative endodontic treatment (RET) includes procedures that allow root development, increased wall thickness and apical closure. The production of totally autologous matrices using a second generation platelet concentrate known as platelet and leukocyte rich fibrin (L-PRF^® - Intra-Lock International - Boca Raton, FL, USA) containing growth factors and entrapped cytokines in a free polymerization fibrin network / matrix, may increase the regeneration potential of soft and hard tissues. We present a clinical case where modified regenerative endodontic procedures were used, using L-PRF® as a matrix and source of growth factors for treatment of a necrotic immature superior lateral incisor with open apex and associated chronic apical abscess, introducing the theme of "Bio- Obturation". Schlagwörter: Regenerative endodontics, immature permanent teeth, necrotic pulp and apical periodontitis, L-PRF