The Efficacy of Lyophilized Platelet-Rich Fibrin in Treatment of Periodontal Intra-Bony Defects (A Comparative Clinical, Radiographic and Biochemical Study)

Periodontitis is a multi-factorial inflammatory process affecting the periodontal tissues. Among the characteristic signs of periodontal disease is loss of alveolar bone support. The risk of further alveolar bone loss and the probability of tooth loss increases with the presence of intra-bony defects.

Periodontal intra-bony defects (IBDs) are osseous defects with specific morphology, the bottom of these defects is located more apically than the alveolar crest and they are surrounded by bony walls on 1-, 2-, or 3- sides, with the tooth root forming the additional wall. The prevalence of these defects is significantly lower than supra-crestal periodontal defects.

Among the main goals of periodontal therapy is to regenerate the lost periodontal tissues after arresting the progress of the disease. Surgical management of periodontally affected sites includes conventional and regenerative procedures. The conventional modality of surgical debridement allows for reliable access to root surfaces leading only to healing by repair. While the regenerative treatment options allow for the regeneration of destroyed periodontal ligament and bone. Guided tissue regeneration (GTR), placement of bone grafting materials, the addition of biologic mediators and a combination of such techniques are the different forms of periodontal regenerative techniques.

Bone grafts (BGs) and substitutes are classified into autogenic, allogenic, xenogenic and synthetic bone grafts. Synthetic nanocrystalline hydroxyapatite (NCHA) has been extensively applied as bone graft replacement material and characterized by its osteoconductive properties and improved osseointegrative features. The size of the particle was found to be around 18 nm, allowing for quicker vital bone substitution. It has been proved that NCHA can enhance the adhesion of the bone formative cells (osteoblasts) more than micromaterials. Furthermore, the nano-sized particles provide special properties to NCHA such as ahydrated surface layer, a large surface/volume ratio, this layer is actively involved in the homeostasis process, ionic exchange and other techniques involved in the osteogenesis regulation. NCHA is osteoconductive but has inferior osteoinductive properties; therefore, one of the efforts to increase the ability of this material is to combine it with other bioactive materials such as platelet-rich fibrin (PRF).

Platelet-rich fibrin is a second-generation platelet concentrate that has been widely used in the treatment of bone deficiency and its main action is derived from its high content of platelets that release many growth factors (GFs) and cytokines. However, freshly prepared PRF must be used immediately in order to retain the bioactivity of growth factors. In addition, the bio-degradation rate of PRF is fast and irregular, along with the rapid release of growth factors, and then enzymatically hydrolyzed.