“…The average surface roughness of the ceramic articulating surfaces (0.016 μm and 0.015 μm for the alumina head and the zirconia cup, respectively) was also relatively lower than previously investigated PoP (Kandemir et al, 2020a) and MoP (Kandemir et al, 2021) surfaces. For the head and the cup of an explanted all-PEEK NuNec cervical disc (a type of PoP cervical disc), average roughness of 0.067 μm and 0.037 μm was measured, respectively (Kandemir et al, 2020a). For an explanted Mobi-C cervical disc (a type of MoP cervical disc), which consisted of cobalt chromium (CoCr) superior (curved articulating surface) and inferior endplates (flat articulating surface) and an ultrahigh molecular weight polyethylene (UHMWPE) insert (which had curved superior and flat inferior surfaces), average roughness values of 0.016 μm (superior curved CoCr endplate) 0.055 μm (inferior flat CoCr endplate) 1.210 μm (curved UHMWPE surface) and 0.446 μm (flat UHMWPE surface) were measured, respectively (Kandemir et al, 2021).…”