Platelet-Rich Fibrin: A Viable Therapy for Endodontic-Periodontal Lesions? A Preliminary Assessment

Background and Objectives: The endodontic system and the periodontium are closely interrelated and the infection of both leads to the appearance of endodontic-periodontal lesions. Along with the endodontic and periodontal classic treatment, in most cases, there is a need for regenerative periodontal therapy for the repair of the damaged tissue. One material that stimulates bone healing is represented by platelet-rich fibrin (PRF). The aim of this study was to determine if the inclusion of PRF in the treatment protocol of endodontic-periodontal lesions is effective. Materials and Methods: This review was conducted according to the PRISMA guidelines. Four databases, MEDLINE (through PubMed), Scopus, Web of Science, and Google Scholar, were used in order to find all significant articles on the topic. Relevant keywords were used in different combinations. Results: The inclusion criteria were met by six studies, published between 2014 and 2020 and they were selected for the review. The use of PRF for the regenerative therapy of endodontic-periodontal lesions showed favorable outcomes in all of the studies included, with significant reductions in the probing depths. Conclusion: While platelet-rich fibrin may be beneficial, further research is needed.

Mechanical, chemical, structural analysis and comparative release of PDGF-AA from L-PRF, A-PRF and T-PRF - an in vitro study

Background Platelet concentrates have been popularly used in regenerative periodontal therapy as they are autologous in origin and they provide a supernatural concentration of platelets, growth factors and leukocytes. The release profile of various growth factors is considered important during the various phases of wound healing with the most important being the inflammatory phase where the release of the growth factors help in recruitment of cells and in collagen production. With the more recent modifications of PRF namely A-PRF and T-PRF, the mechanical and chemical degradation properties have also improved. The aim of the present study was to correlate the release profile of PDGF-AA from various forms of platelet concentrates (L-PRF, A-PRF, T-PRF) based on their mechanical and chemical properties. Methods Blood samples were drawn from 2 male and 3 female systemically healthy patients between 20 and 25 years of age who were about to undergo periodontal regeneration for PRF preparation. The blood sample was immediately centrifuged using a table top centrifuge (Remi R4C) at 1060 rpm (208 x g) for 14 min for A-PRF preparation, 1960 rpm (708 x g) for 12 min for L-PRF preparation and 1960 rpm (708 x g) for 12 min in titanium tubes for T-PRF preparation. Tensile test was performed using universal testing machine. The in vitro degradation test of the prepared PRF membranes were conducted by placing the PRF membrane in 10 ml of pH 7.4 PBS on an orbital shaker set at 50 rpm. SEM evaluation of the PRF membrane was done under both low and high magnification. In order to determine the amount of released growth factor PDGF-AA at 15 min, 60 min, 8 h, 1 day, 3 days, and 10 days, samples were placed into a shaking incubator at 37 °C to allow for growth factor release into the culture media. Results On comparing the three PRF membranes, it was found that T-PRF contained the maximum tensile strength (404.61 ± 5.92 MPa) and modulus of elasticity (151.9 ± 6.92 MPa). Statistically significant differences between the three groups were found on comparing the groups for their mechanical properties. In the degradation test, it was found that the maximum amount of degradation was found in L-PRF (85.75%), followed by A-PRF (84.18%) and the least was found in T-PRF (82.27%). T-PRF released the highest amount of PDGF-AA (6060.4 pg/ml) at early time points when compared to A-PRF (5935.3 pg/ml). While T-PRF had rapid release of PDGF-AA, A-PRF had a sustained release of growth factors released at later time points. Conclusion Results from the present study indicate that A-PRF is the most favourable form of platelet concentrate in regenerative periodontal therapy as it has a sustained release of growth factors over time.

Biomechanical behavior of periodontally compromised dento-alveolar complex before and after regenerative therapy - a proof of concept

Introduction/Objective. Finite element analysis (FEA) is mathematical method which can be used for the assessment of biomechanical behavior of dento-alveolar complex. The objective was to analyze biomechanical behavior changes of teeth and supporting tissues under occlusal load in cases of horizontal and vertical alveolar bone loss, to assess potential impact of tooth displacement and altered stress distribution on further damage, and to evaluate the impact of regenerative periodontal therapy. Methods. Three patient-specific three-dimensional-Finite-Element (3D FE) models were developed from the acquired cone beam computed tomography, comprising the patient's upper left canine, first and second premolar, and adjacent bone. Model 1 represented horizontal bone loss; Model 2 included intrabony defect along distal aspect of tooth #24. Model 3 represented situation six months after the regenerative periodontal surgery. Displacement, Von Mises, and principal stresses were evaluated through FEA, under moderate vertical occlusal load. Results. FEA demonstrated that in model with vertical bone loss significant tooth displacement was present, even though the clinically evident tooth mobility was absent. Biomechanical behavior and stress distribution of teeth and surrounding tissues under moderate occlusal load was much more altered in case with vertical bone loss in comparison with horizontal bone loss. Six months following the regenerative therapy, the values of all evaluated parameters were noticeable reduced. Conclusion. Regenerative periodontal therapy improved the biomechanical characteristics of the affected teeth and the related periodontal structures.

The Application of Three-Dimensional Printing Model and Platelet-Rich Fibrin Technology in Guided Tissue Regeneration Surgery for Severe Bone Defects

A 36-year-old male patient diagnosed with severe chronic periodontitis was treated with novel surgery for his maxillary right lateral incisor. Preoperatively, a 3D printer was used, based on CBCT datasets, to produce a photosensitive resin bony anatomy replica. The patient's blood was centrifuged to obtain advanced platelet-rich fibrin (A-PRF) and injected platelet-rich fibrin (I-PRF), then mixed with Bio-Oss and packed onto the 3D replica to form the ideal shape. The replica was positioned at the planned sites without changes. The A-PRF membrane was applied over the replica as well as a Bio-Gide collagen membrane. Fifteen months after the surgery, clinical and radiographic followup revealed greatly reduced pocket depths and significant 3D alveolar bone fill at the treatment site. Based on these short-term results, the initial 3D printing surgical temple assisted guided tissue regeneration method resulted in significant clinical and radiographic improvements; A-PRF/I-PRF should be considered an ideal biomaterial for regenerative periodontal therapy.