Surface engineering of PMMA maxillofacial prostheses with hydroxyapatite for improved bioactivity

Polymethylmethacrylate (PMMA) maxillofacial prostheses are widely used in facial bone reconstruction, providing functional restoration, aesthetic rehabilitation, and improved quality of life. However, due to its bioinert nature, PMMA exhibits limited tissue integration. This study aimed to coat PMMA maxillofacial prostheses with hydroxyapatite (HA) to enhance the material’s bioactivity and interaction with biological tissues. Two porous configurations fabricated by additive manufacturing were tested: Prototype A, with ellipsoidal pores, and Prototype B, with a regular hexagonal architecture. Mechanical evaluation demonstrated average values of 33.01 MPa for tensile strength, 3.18 MPa for impact toughness, and 62.65 MPa for flexural strength, confirming structural stability under functional demands. Structural analysis revealed the formation of calcium phosphate phases with low crystallinity, predominantly hydroxyapatite and octacalcium phosphate, while surface examination showed a continuous granular coating with pseudo-spherical agglomerates. Bioactivity assays indicated that the HA-coated prostheses were capable of inducing apatite precipitation, in contrast to uncoated PMMA, which remained bioinert. Prototype A favored permeability and surface area for potential cell adhesion, whereas Prototype B ensured uniform porosity and predictable load distribution. The integration of controlled porous architecture with HA deposition resulted in composite prostheses that combined mechanical robustness with surface bioactivity, representing a promising approach for improved maxillofacial reconstruction.