Effect of ultraviolet photofunctionalisation on the cell attractiveness of zirconia implant materials

Abstract

Ultraviolet (UV) light treatment of implant surfaces has been demonstrated to enhance their bioactivity significantly. This study examined the effect of UV treatment of different zirconia surfaces on the response of primary human alveolar bone-derived osteoblasts (PhABO). Disks of two zirconia-based materials with two different surface topographies (smooth, roughened) were exposed to UV light. Qualitative and quantitative assessment of PhABO on zirconia surfaces, by means of immunofluorescence, scanning electron microscopy and DNA quantification at 4 and 24 h revealed a higher number of initially attached osteoblasts on UV-treated surfaces. Cell area and perimeter were significantly larger on all UV-treated surfaces (p < 0.05). The proliferation activity was significantly higher on both roughened UV-treated surfaces than on untreated samples at day 3 of culture (p < 0.05). The expression levels of collagen I, osteopontin and osteocalcin at day 14 and alkaline phosphatase activity at day 7 and 14 of culture period were similar among UV-treated and untreated surfaces. Alizarin-Red-Staining at day 21 demonstrated significantly more mineralised nodules on UV-treated samples than on untreated samples. Contact angle measurements and X-ray photoelectron spectroscopy showed that UV light transformed zirconia surfaces from hydrophobic to (super-) hydrophilic (p < 0.05) and significantly reduced the atomic percentage of surface carbon. The results showed that UV light pre-treatment of zirconia surfaces changes their physicochemical properties and improves their attractiveness against PhABO, primarily demonstrated by an augmented cell attachment and spreading. This may result in faster healing and better bone-to-implant contact of zirconia implants in vivo following such a pre-treatment.

Generation of Osteosarcomas from a Combination of Rb Silencing and c-Myc Overexpression in Human Mesenchymal Stem Cells

“…1C). The in vitro soft agar assay also showed that cells with SiRb‐OeMyc have a greater ability to form colonies than different single or combined gene mutations, and the ability to form colonies is even greater than that of MG63, an OS cell line as positive control , (Fig. 1D).…”

“…Cells were subcultured by 0.25% trypsin (Thermo Fisher) digestion. With the capacity for osteogenesis and colony formation , , MG63 was used as the positive control in osteogenic and tumorigenic assays. Spheroid formation assay was performed in tumor sphere medium (TSM; serum‐free DMEM/F12 [Thermo Fisher] containing N2‐supplement [Thermo Fisher], human epidermal growth factor [20 ng/ml; Peprotech, Rocky Hill, NJ, http://www.peprotech.com], and basic fibroblast growth factor [10 ng/ml, Peprotech]), and the sphere numbers were counted at day 14.…”

The Effect of UV Treatment on the Osteoconductive Capacity of Zirconia-Based Materials

“…Hence, UV treatment of zirconia has been proposed to induce electron excitation from the valence band to the conduction band, provided the photon energy is sufficient [24]. Compared to titanium, zirconia requires photon energy larger than 5 eV to cause electrons to go from the V to C band to express its photocatalytic activity [28].…”

Surface Characterization and Cell Adhesion of Different Zirconia Treatments: An in vitro Study

“…Securing a constant hydrophilic level should open the door to investigations that would impact the long-term prognosis of zirconia implant in combination with other treatment, as ultraviolet photofunctionalization helps in attracting cell on zirconia surface. 49 Further studies should be conducted to validate the results of this study.…”