326 Resorbable Composite Materials for Fracture Fixation

Abstract Introduction Titanium-based fracture fixation devices often necessitate removal in the maxillofacial region. Resorbable composite implants negate the need for a revision operation; however, concurrent devices either possess a prolonged degradation profile or bioactivity, resulting in undesirable bone deposition. To that end, a novel, fast-resorbing, non-bioactive composite material is proposed, which still possesses an osteoinductive potential, thereby aiding fracture healing. Method Three bioglasses were available (NCL1-3) as filler material. NCL2 was selected and different concentrations (5%; 20%) were added to reinforce medical grade poly(lactic-co- glycolide) (PLGA). The final compression moulded samples underwent material characterisation and an 8-week degradation assay. Results No significant difference was found between the cytotoxicity of the glasses and both the positive (apatite wollastonite) and negative (absence of glass) controls in relation to mesenchymal stem cells or osteoblasts. pH and weight change analyses showed an increased rate of degradation with an increase in glass concentration. Although reinforcement with NCL2 did not increase the mechanical properties of the polymer, no significant difference was present between the mechanical properties of the composites, and, as made, both 5% and 20% composites had flexural strengths of 13MPa±5, which did not decrease significantly during degradation. Conclusions NCL1-3 are non-toxic in the context of fracture healing. The PLGA/NCL2 composite is not suitable for fracture fixation as produced currently, due to increased polymer degradation and lower mechanical properties. However, 20% compositions are recommended for future research, as they would hypothetically provide a superior osteoinductive response without significantly lowering the mechanical properties of the composite.