In vitro evaluation of novel composite bioceramic filaments for alveolar bone regeneration.

Background/purpose: Alveolar bone defect repair remains a major clinical challenge in oral and maxillofacial reconstruction. This study developed 3D-printable composite filaments combining polylactic acid (PLA) with bioceramic powders and evaluated their physicochemical properties and in vitro osteogenic potential for alveolar bone graft applications. Materials and methods: Filaments were fabricated via hot processing and tetrahydrofuran (THF) solvent casting, blending PLA with hydroxyapatite (HA) and β-tricalcium phosphate (β-TCP) at a 7:3 ratio. Four groups, H-PLA (heated PLA), H-MIX (heated PLA with HA/β-TCP), T-PLA (THF-processed PLA), and T-MIX (THF-processed PLA with HA/β-TCP) groups, underwent material characterization such as Fourier transform infrared spectroscopy (FTIR), X-ray diffractometer (XRD), scanning electron microscopy (SEM), and compressive strength testing, and MC3T3 cell-based assays for biocompatibility assessment. Results: H-MIX and T-MIX significantly enhanced compressive strength and osteogenic mineralization compared to PLA-only groups. HA/β-TCP was uniformly dispersed within the PLA matrix. Cell proliferation peaked on day 3, with both composite groups showing higher viability than controls (P < 0.01). Alkaline phosphatase (ALP) activity increased by day 7, with T-MIX significantly higher than H-PLA and T-PLA (P < 0.05). On day 14, T-MIX and H-MIX showed markedly greater mineralization, with T-MIX displaying the highest calcium deposition (P < 0.05 to P < 0.001). Conclusion: Composite scaffolds made by thermal and solvent casting showed enhanced mechanical strength and osteogenic activity in vitro. T-MIX outperformed other groups in compressive strength, ALP activity, and calcium deposition. These results indicate that HA/β-TCP-reinforced PLA filaments, especially T-MIX, are promising for alveolar bone repair.