Evaluation of Blood Clot, Platelet-rich Plasma, Platelet-rich Fibrin, and Platelet Pellet as Scaffolds in Regenerative Endodontic Treatment: A Prospective Randomized Trial

Introduction: Regenerative endodontic procedures (REPs) using autologous platelet concentrates as scaffolds can improve the biologic outcome of treatment. This prospective, randomized trial compared the clinical and radiographic performance of REPs using platelet rich plasma (PRP), platelet-rich fibrin (PRF), a platelet pellet (PP), and an induced blot clot (BC). Methods: Sixty-seven healthy children (aged 8-11 years) with 88 immature necrotic incisors were included. After the root canal disinfection step, the teeth were randomly assigned into 1 of the following groups (n = 22/group) according to the scaffold used: PRP, PRF, PP, and BC. In the PRP, PRF, and PP groups, the platelet concentrates were introduced into the root canal without prior induction of apical bleeding. Treatment outcomes were assessed using a combined clinical and radiographic scoring system, whereas the changes in root dimensions were compared using linear measurements of root length and width with Image) (National Institutes of Health, Bethesda, MD) and Turboreg (Biomedical Imaging Group, Swiss Federal Institute of Technology, Lausanne, Switzerland) and planar measurements using the radiographic root area (RRA) and radiographic canal area (RCA) techniques. One-way analysis of variance, the Duncan multiple range test, the Kruskal-Wallis test, the Mann Whitney U test, and chi-square dependency tests were used for statistical analysis of data (all P=.05). Results: Except for 2 teeth in the PRF and BC groups, all teeth showed similar and high success scores (periapical healing, radiographic root development, and positive response to sensitivity tests) after an average follow-up time of 28.25 +/- 1.2 months. Of all teeth, 73.9% showed complete apical closure with similar closure rates among groups (P > .05) and a greater tendency for conical-shaped apical closure than a blunt apex. Although linear measurements indicated a similar increase in root length and width among all groups (P > .05), the RRA of the BC group was significantly greater than those of the PRF and PP groups, and the RCA of the BC group was significantly greater than PRP, PRF, and PP (all P <.05) when the follow-up time was not used as a factor. Eighty-six percent of the teeth showed a positive response to sensitivity tests with similar initial response times (P > .05). Conclusions: PRP, PRF, and PP can yield similar clinical and radiographic outcomes to BC without the need for prior apical bleeding and with significantly less tendency for root canal obliteration. RRA and RCA may reveal minor differences that cannot be determined by linear measurements.