Bone formation in peri-implant defects grafted with microparticles

Background and Aim: The activation of platelets by thrombin, apoptosis and mechanical stress results in the release of small membrane vesicles from the platelet surface, so-called microparticles (MPs). MPs interact in various ways with their environment. Experimental data suggest that MP play an integral role in modulating innate and adaptive immunity, hemostasis, angiogenesis and bone-forming cell activation. Thus, MP application represents a promising method for enhancing the regeneration of peri-implant defects. This study aimed to evaluate the healing of peri-implant defects grafted with microparticles (MPs). Material and Methods: Six domestic pigs received nine standardized defects at the calvaria, and an implant was inserted in the middle of each defect. The space between the implant and lateral bone portion was filled with thrombocytes +MP (n=18) or MP (n=18) or left unfilled (n=18). After 14 and 28 days, three animals were sacrificed and specimens removed for further processing. Samples were microradiographically and histologically analyzed. In addition, we immunohistochemically stained for anti-vWF as a marker of angiogenesis. Results: In the case of bone regeneration and vessel formation, the null hypothesis can be partially rejected. After 14 and 28 days, no significant difference was observed within groups regarding de novo bone formation and osseointegration. However, superior vessel formation was found at both time points. Conclusion: MPs represent a promising treatment option to accelerate peri-implant vessel formation. Further studies are needed to investigate the regenerative properties of MPs more precisely. Keywords: Microparticles, Dental implant, Bone regeneration, Histology, Immunohistochemistry, Animal Model