Osteoblast Responses to Different Surface Morphology and Roughness of 3D-printed PEEK Implants and Prosthesis

Abstract

PEEK has been used widely in clinical applications during the past decades due to the excellent biocompatibility, low density, chemical resistance, radiolucency, and mechanical strength resembling human bone. As one of the fastest growing and most popular AM technologies, recently FFF has become a possible way to fabricate patient-specific PEEK objects to reconstruct severe bone loss. But to the best of our knowledge, studies focusing on the bioactivities of FFF-printed PEEK, e.g., cell adhesion, metabolic activity, and proliferation, are still lacking. Therefore, the aim of this study is to evaluate the effect of the specific FFF printing structure and surface morphology on cell adhesion, metabolic activity, and proliferation of SAOS-2 osteoblasts.

The PEEK disk samples were successfully manufactured by an FFF printer using medical grade PEEK filament with a layer thickness of 200 µm. Then the sample surfaces were modified by polishing and by grit-blasting to obtain increased surface roughness [25]. Cell metabolic activity and proliferation were analyzed by CCK-8 assay after culturing for one day, three days, and five days. After five days, as a final test, the sample surface coverage of osteoblasts was measured by crystal violet again.

The result indicated that the FFF printed PEEK with particular printing structures and high roughness had improved bioactivity compared with polished and grit-blasted surfaces, especially in cell metabolic activity, proliferation, and long-term cell adhesion [25]. FFF printing features had an enlarged surface area, which could provide more bonding spots for cells to spread and migrate, which were beneficial to cell metabolic activity and proliferation. In the early stage of cell adhesion, surface wettability played an important role. While as the culture time extent, the influence of the surface morphology and roughness became increasingly apparent.

FFF-manufactured samples have highly rough and unique printing topographies, which cannot be achieved by dental grit-blasting processes. These manufacturing features are more suitable for cell attachment, metabolic activity, and proliferation than the polished or grit-blasted surfaces. Therefore, based on the limitations of this research, FFF-printed PEEK could have great potential in bone reconstruction and replacement in oral and cranio-maxillofacial surgeries.