In Situ Casting of Platelet Rich Plasma/SiO2/Alginate for Bone Tissue Engineering Application in Rabbit Mandible Defect Model

STATEMENT OF THE PROBLEM: The administration of both platelet rich plasma (PRP) and silicon dioxide (SiO(2)) to the bone defects accelerates bone repair and regeneration. Appli-cation of both of them may show synergistic regenerative effects PURPOSE: Our objective was to evaluate the possible synergistic osteogenic effects of PRP and SiO(2) by injecting them using an ad hoc device. MATERIALS AND METHOD: In this experimental study, PRP/SiO(2) scaffolds were fabricated by in situ casting method with the help of CaCl(2) as the gelation factor and alginate as the stroma; and then, the biodegradability and spatial arrangement were assessed. The injecta-ble scaffold was introduced into the 40 rabbit mandibular defects by an ad hoc two-channel injecting device. Five defects received PRP/SiO(2)/alginate as the treatment; the other sets of defects were treated by PRP/alginate, SiO(2)/alginate, and the last five defects served as the control groups by getting only alginate injections. The osteogenicity of the scaffolds was evaluated by radiological and histological procedures; they were then compared with each other. Analysis of variance and least significant difference tests were used to analyze the data RESULTS: The SiO(2)-treated group showed a significant higher bone area compared to PRP/ SiO(2)-treated groups on day 40 (p= 0.013). The number of osteocytes was higher in SiO(2)-treated than the control groups on both 20 and 40 days (p= 0.032 and 0.022, respectively). The number of osteoclast was also higher in SiO(2)-treated than PRP-treated group (p= 0.028). In addition, the cells of this group had just started to create Haversian systems in newly formed bone tissues. CONCLUSION: Silica demonstrated a superior osteogenic activity over PRP in both short and long term periods. Evidently, they showed no synergistic regenerative effects. Our ad hoc device was efficiently capable of inserting the scaffolds into the injured sites with no diffi-culties or complications.