Bone Abstracts

This study was performed to characterize the effects of calcium phosphate coated and hydroxyapatite coated zirconia compared to smooth surfaced zirconia with bone marrow-derived osteoblast culture.

Bone marrow-derived osteoblasts were cultured on i) smooth zirconia, ii) zirconia coated with calcium phosphate (CaP), and iii) zirconia coated with hydroxyapatite (HA). The tetrazolium-based colorimetric assay (MTT test) was used for examining the attachment of cells. Cellular morphology was examined by scanning electron microscopy (SEM) and alkaline phosphatase (ALP) activity was measured to evaluate the cell differentiation rate. X-ray photoelectron spectroscopy (XPS) was employed for the analysis of surface chemistry. The genetic expression of the osteoblasts and dissolution behavior of the coatings were observed. ANOVA was conducted to assess the significance level of the differences between the groups.

From the MTT assay, there was no significant difference between smooth zirconia and surface coated zirconia (P>0.05). From the SEM image, cells on all three groups of discs were irregularly triangular or elongated in shape with formation of filopodia. From the ALP activity assay, the optical density of osteoblasts on smooth zirconia discs was slightly higher than that of osteoblasts on surface treated zirconia discs (P>0.05). Most of the genes related to cell adhesion showed similar expression level between smooth zirconia and surface treated zirconia. The dissolution rate of Ca²⁺ and P⁻ was higher with CaP coating than HA coating.

The attachment and growth behavior of bone-marrow-derived osteoblasts cultured on smooth zirconia and surface coated zirconia showed comparable results. However, the HA coating showed more time-dependent stability compared to the CaP coating.