Fabrication and characterization of 3D-printed polymeric-based scaffold coated with bioceramic and naringin for a potential use in dental pulp regeneration (in vitro study).

Aim: 3D-printed scaffolds loaded with healing directed agents could be employed for better treatment outcome in regenerative dentistry. The aim of this study was to fabricate and characterize simple 3D-printed poly lactic acid (PLA) scaffolds coated with nanoHydroxyapatite (nHA), Naringin (NAR), or their combination, and testing their morphological, chemical, mechanical, antibacterial, biocompatible and bioactive properties.

Methodology: Two variants pore sizes, 300 and 700 μm, of 3D-printed PLA disc scaffolds measuring (10 × 1 mm) were fabricated. These scaffolds were dip-coated with nHA, NAR, or both (nHA/NAR). Field emission scanning electron microscopy (FeSEM), energy-dispersive X-ray spectroscopy (EDX), Fourier transforms infrared (FTIR), compressive and flexural strength testing was employed for optimizing pore size. Then, antibacterial activity against isolated Streptococcus mutans and Enterococcus faecalis, and cytotoxicity against normal human fibroblast were assessed. Additionally, appetite formation on scaffold surfaces was assessed after storage in simulated body fluid (SBF) for 14 days by further using FeSEM, EDX and XRD.

Results: FeSEM showed uniform structure for 3D-printed scaffolds in both pore size designs, and a consistent surface coating with nHA and NAR, which were further confirmed by EDX and FTIR. However, mechanical testing revealed statistical significant higher compressive and flexural strengths (p < .000) for 300 μm pore size scaffolds. Statistical significant antibacterial activities (p < .05) were also found with PLA/NAR, and PLA/nHA /NAR scaffolds in comparison with neat. The MTT assay revealed biocompatibility of PLA, nHA and NAR, with the combinations of the latter two working synergistically. Lastly, the formation of a calcium-phosphate appetite layer was recognized on the surface of PLA/nHA, PLA/nHA/NAR scaffold after being stored in SBF.

Conclusions: 3D-printed, 300 μm pore size, PLA scaffold coated with a combination of nHA and NAR showed the best surface characteristics and improved mechanical, antibacterial and biocompatible properties for further investigation in regenerative studies.