Biomechanically Advanced Polymer-Based Biocomposites for Oral and Maxillofacial Reconstruction

Abstract

<p><strong>Objectives</strong>: The increased demand for implants but the availability of limited material types remain a substantial clinical challenge. Therefore, we aimed to develop a subverted traditional material that could be generalizable to any dental composite system while overcoming the limitations associated with conventional implants.<br><strong>Methods</strong>: The resin-based biocomposites were synthesized by mixing 2 wt.% of nano-hydroxyapatites (nHAPs, D: 50-200 nm) and 10-20 wt.% of nano-glass particles (D<700nm) with photocurable dental monomer system (Figure 1A). The samples were randomly divided into a control and a test group with or without helium-oxygen cold plasma treatment, and tissue culture plates (TCPs) were used as a positive control. Mechanical properties were investigated through compression tests. <em>In vitro</em> cell proliferation with adherence, live/dead assay, and osteogenic differentiation including mineralization of MC3T3-E1 were evaluated while cytoskeleton structure was visualized by scanning electron microscopy (SEM) and confocal laser scanning microscopy (CLSM). The <em>in vivo</em> study was performed on the left femur of 28 Sprague Dawley rats followed by histology analyzed via Toluidine Blue O staining.<br><strong>Results</strong>: With the increased nano-fillers fraction, the mean value of the compressive strength and modulus increases from 104.04 to 121.25 MPa (16.5%) and from 2.18 to 3.41 GPa (56.4%), respectively (Figure 1B). After five days of cultivation of MC3T3-E1 on the plasma-treated surface, 99.35% viable cells were found (Figure 1C a). Cell adhesion and proliferation results revealed the treatment group showed higher values compared to the control group at 6 h and 5 d, respectively (Figure 1C b-c). The level of alkaline phosphatase remarkably increased from 7 to 14 d. The absorbance of Alizarin Red in the treatment group (2.90 ± 0.41) was significantly higher than in TCPS (3.02 ± 0.45) (<em>p</em><0.05). Finally, new bony growth and its strong adherence on the implant surface was also observed in the femur defect model post 4- and 10-week implantation.<br><strong>Conclusions</strong>: Collectively, the metal-free medical implants possessed strong mechanical strength, exhibited outstanding osteointegration activity, and its osteogenesis enhanced through cold plasma surface treatment.<br></p>