Effect of calcium phosphate coating crystallinity and implant surface roughness on differentiation of rat bone marrow cells

Abstract

In this study, we examined the effect of calcium phosphate (Ca-P) coating crystallinity and of surface roughness on growth and differentiation of osteogenic cells. Grit-blasted titanium substrates were provided with Ca-P coatings of different crystallinities. Rat bone marrow (RBM) cells were cultured on these substrates and on noncoated rough and smooth titanium substrates. After specific culture times, expression of osteogenic markers by the cells was studied. Cells cultured on crystalline coatings and on titanium substrates proliferate, express alkaline phosphatase, osteocalcin (OC), and show mineralization of the extracellular matrix. Rough titanium substrates only express low OC levels. Significantly higher OC levels were expressed on smooth titanium, and even higher levels on the crystalline Ca-P coating. No difference was found in calcification between smooth and rough titanium. The crystalline coating showed more calcification than the titanium substrates. When substrates without cells were incubated in medium, precipitation of calcium was found. On the titanium substrates, this precipitate disappeared after prolonged incubation. The precipitate on the crystalline coating was stable and increased with longer incubation times. On the amorphous coatings, no proliferation and differentiation of RBM cells were found. After longer culture periods, substrates showed extensive dissolution. Cells on the amorphous coatings did express high levels of prostaglandin E2. In contrast, prostaglandin E2 expression was low for the other substrates. We conclude that crystalline Ca-P coatings stimulate differentiation of RBM cells, to a higher extent than titanium substrates. Surface roughness only has a limited effect on phenotype expression of the cells. In contrast, thin amorphous coatings show negative effects on the growth and differentiation of cultured RBM cells.

Bone formation in CaP‐coated and noncoated titanium fiber mesh

“…This corroborates with previous in vitro studies of our group in which the application of a CaP coating on solid Ti discs has been shown to delay the proliferation of rat bone marrow cells by 8 days, while differentiation was stimulated by 16 days. 36,38 This positive effect of a CaP coating can be mediated by an increased level of Ca 2+ ions that results from the superficial dissolution of the coating. Osteoblast-like cells have been shown to possess calcium receptors on their surface.…”

Femtosecond laser microstructuring of zirconia dental implants

“…19 Additionally, they require special laboratory conditions, and they sometimes demand special conditions including contaminant-free working areas and are usually restricted to conductive materials. 20,21 As far as zirconia is concerned, electrical techniques are precluded, and acid or alkaline-etching techniques do not give rise to high-surface roughness levels, because the original material is manufactured using high-isostatic pressure to make it resistant to chemical, physical, or wear changes 22 . The reason for these geometric, physical, or chemical modification techniques is to enhance surface-cell interactions and to stimulate cellular activity.…”

The Role of Titanium Surface Nanostructuring on Preosteoblast Morphology, Adhesion, and Migration

“…However, the majority of chemical methods modify not only topography, but also other surface features such as chemical composition, [25] wettability, [26] crystallinity, [27] and adsorption ability. [28] These surface observables can also modulate cell behavior [27,[29][30][31] (for more information about surface modification strategies and cellular recognition of these surfaces see the review papers [32,33] ) and it is difficult to distinguish which factor leads to the observed cell response.…”