L-PRF (leukocyte- and platelet-rich fibrin) is one of the four families of platelet concentrates for surgical use and is widely used in oral and maxillofacial regenerative therapies. The first objective of this article was to evaluate the mechanical vibrations appearing during centrifugation in four models of commercially available table-top centrifuges used to produce L-PRF and the impact of the centrifuge characteristics on the cell and fibrin architecture of a L-PRF clot and membrane. The second objective of this article was to evaluate how changing some parameters of the L-PRF protocol may influence its biological signature, independently from the characteristics of the centrifuge. In the first part, four different commercially available centrifuges were used to produce L-PRF, following the original L-PRF production method (glass-coated plastic tubes, 400 g force, 12 minutes). The tested systems were the original L-PRF centrifuge (Intra-Spin, Intra-Lock, the only CE and FDA cleared system for the preparation of L-PRF) and three other laboratory centrifuges (not CE/FDA cleared for L-PRF): A-PRF 12 (Advanced PRF, Process), LW-UPD8 (LW Scientific) and Salvin 1310 (Salvin Dental). Each centrifuge was opened for inspection, two accelerometers were installed (one radial, one vertical), and data were collected with a spectrum analyzer in two configurations (full-load or half load). All clots and membranes were collected into a sterile surgical box (Xpression kit, Intra-Lock). The exact macroscopic (weights, sizes) and microscopic (photonic and scanning electron microscopy SEM) characteristics of the L-PRF produced with these four different machines were evaluated. In the second part, venous blood was taken in two groups, respectively, Intra-Spin 9 ml glass-coated plastic tubes (Intra-Lock) and A-PRF 10 ml glass tubes (Process). Tubes were immediately centrifuged at 2700 rpm (around 400 g) during 12 minutes to produce L-PRF or at 1500 rpm during 14 minutes to produce A-PRF. All centrifugations were done using the original L-PRF centrifuge (Intra-Spin), as recommended by the two manufacturers. Half of the membranes were placed individually in culture media and transferred in a new tube at seven experimental times (up to 7 days). The releases of transforming growth factor β-1 (TGFβ-1), platelet derived growth factor AB (PDGF-AB), vascular endothelial growth factor (VEGF) and bone morphogenetic protein 2 (BMP-2) were quantified using ELISA kits at these seven experimental times. The remaining membranes were used to evaluate the initial quantity of growth factors of the L-PRF and A-PRF membranes, through forcible extraction. Very significant differences in the level of vibrations at each rotational speed were observed between the four tested centrifuges. The original L-PRF centrifuge (Intra-Spin) was by far the most stable machine in all configurations and always remained under the threshold of resonance, unlike the three other tested machines. At the classical speed of production of L-PRF, the level of undesirable vibra...

The aim of this study was to describe the histological and clinical outcome of "Dentin block" (a mixture of: autologous particulate dentin, leukocyte and platelet rich fibrin (L-PRF) and liquid fibrinogen) in an alveolar ridge preservation. Material and Methodsextraction sockets were grafted with "Dentin Block" a mixture of particulate autologous dentin with chopped leukocyte-platelet rich fibrin (L-PRF) membranes at a 1:1 ratio and liquid fibrinogen as binder. 2 grafted sites were followed at 4 and 5 months, and 6 sites at 6 months. Biopsies were taken from the core of the grafted site for histologic and histomorphometric analysis. ResultsAll patients completed the study without any adverse event. The vertical and horizontal dimensions of alveolar ridge were preserved or even increased after 4, 5 or 6 months and remained stable after 6 months of the implant placement. The histological examination revealed a median relative percentage of bone, dentin, and connective tissue of 57.0, 0.9, and 39.3%, respectively. A comparison of samples at different time points (4, 5, and 6 months) showed a progressive increase in the proportion of bone with a decrease in the proportion of dentin. The bone was compact with normal osteocytes and moderate osteoblastic activity. In 4/10 samples no dentin was observed, in the other samples it represented 1-5% (with geometric fragments). ConclusionsDentin block showed to be a suitable bone substitute in an alveolar ridges preservation model. Clinical Relevance:The promising results of Dentin Block as a bone substitute in alveolar ridge preservation could have an important clinical impact considering this biomaterial brings together the regenerative potential of three autologous products with excellent biological and clinical behavior, low risk of adverse effects and feasible acquisition.

Within the limitations of this pilot study, it can be concluded that L-PRF might show clinical benefits for ridge preservation.

Objective: To explore patient experience for non-surgical periodontal therapy using phenomenography. Methods: This qualitative study was performed in a postgraduate specialist training program in periodontics. Patients reported their experiences through in-depth interviews in order to recognize the impact of non-surgical periodontal therapy on their quality of life and their satisfaction. A homogeneous sampling procedure was used, establishing redundancy after the fifteenth interview. Interviews were audio recorded, transcribed and analyzed by three researchers who codified the answers into categories to determine the emerging topics. Results: The core emerging themes were: (i) lack of information about periodontal disease; (ii) experience during treatment; (iii) treatment implications; and (iv) clinician-patient relationship. Conclusions: Patients seem to have limited knowledge about periodontal diseases. Reasons for attendance mainly include bleeding gums, tooth mobility, and aesthetic problems. Therapy can generate pain, fear, and is considered invasive, whereas dentine hypersensitivity may occur post-operatively. Despite this, patients would be willing to undergo treatment again and were generally satisfied with the level of care and treatment received.