Influence of fabrication method on the biological properties of modified PEEK

To investigate the influence of fabrication method on the biological properties of modified PEEK. Two materials were tested in this study: press and CAD/CAM milled ceramic-reinforced PEEK (BioHPP, Bredent, Germany). The residual diphenyl sulfone in these two materials was detected and their biological effects on human gingival fibroblasts (HGFs) were evaluated by assaying cell viability, apoptosis, and inflammation. Diphenyl sulfone was not detected in press and milled BioHPP. The cell viability of them complied with ISO standards. The mRNA expression levels of Bax and Caspase-3 were up-regulated and that of Bcl-2 was downregulated when HGFs were cultured with the eluates of these two materials. There was no difference in cell viability, apoptosis, and inflammation between them. Hence, the fabrication method did not affect the biological properties of modified PEEK, the press and CAD/CAM milled modified PEEK all presented favorable cytocompatibility despite the expression of apoptosis-associated genes at the mRNA level.