Functionalization of the Implant Surface Made of NiTi Shape Memory Alloy.

To functionalize and improve the biocompatibility of the surface of a medical implant made of NiTi shape memory alloy and used in practice, a clamp, multifunctional layers composed of amorphous TiO2 interlayer, and a hydroxyapatite coating were produced. Electrophoresis, as an efficient method of surface modification, resulted in the formation of a uniform coating under a voltage of 60 V and deposition time of 30 s over the entire volume of the implant. The applied heat treatment (800 °C/2 h) let toa dense, crack-free, well-adhered HAp coating with a thickness of ca. 1.5 µm. and a high crack resistance to deformation associated with the induction of the shape memory effect in the in the deformation range similar to the real implant work after implantation. Moreover, the obtained coating featured a hydrophilic (CA = 59.4 ± 0.3°) and high biocompatibility.

Photofunctionalization effect and biological ageing of PEEK, TiO2 and ZrO2 abutments material.

The aim of this study was to evaluate the effectiveness of UVC photofunctionalization in removing the surface carbon contamination compounds from the most used surfaces utilized in dental implantology: TiO2, ZrO2 and PEEK. Machined samples were treated by UVC light in an Ushio Therabeam SuperOsseo® device for 12 min each. Non-treated disks were set as controls. X-Ray photoelectron spectroscopy was used to monitor the changes in surface chemical composition. Photofunctionalization of the PEEK material has been analyzed here for the first time. The removal of hydrocarbons allowed by UVC irradiation was nearly twofold, and irradiation simultaneously led to an increase of H-O-C=O bonds. For TiO2 and ZrO2 surfaces, the loss of hydrocarbons detected after UVC irradiation was threefold. The chemical stability of surfaces when left at atmospheric conditions after UVC irradiation was monitored during 10 weeks. After 6 weeks the carbon contamination on TiO2 surfaces returned to the level before UVC treatment, while for ZrO2 and PEEK it was 75% and 60% of its initial value, respectively. None of the materials tested displayed any toxicity towards human fibroblasts cultured in direct contact with them, confirming their potential employment for manufacturing of implant abutments. UVC photofunctionalization can be thus regarded as a valid method in order to reverse the detrimental effects of biological ageing of implant surfaces.

Photofunctionalization of dental zirconia oxide: Surface modification to improve bio-integration preserving crystal stability.

The use of zirconium oxide in dental implantology is rapidly increasing as it is regarded as being more aesthetical and biologically friendly than titanium oxide. The interaction of titanium oxide with cells and proteins has proven to be significantly affected by the inevitable atmospheric hydrocarbon contamination, defined as biological ageing. The latter has proven to be effectively reversed by UVC irradiation. Crystal structures of both Zr and Ti oxides are very similar, thus also ZrO2 is prone to contamination by hydrocarbons. In the present study we have characterized the chemical-physical changes occurring to ZrO2 after UVC irradiation. Firstly a reduction by 3-fold of carbon present on its surface. XRD analysis has indicated that UVC irradiation treatment does not affect the crystalline structure of ZrO2, suggesting that it is possible to improve cell attachment on the surface without sacrificing the mechanical strength of the material. In addition a chemical model of interaction of cell surface proteins with the almost carbon free ZrO2 surface obtainable after UVC irradiation is proposed, pointing to the important role likely played by integrins and RGD sequences originating in soluble proteins adsorbed at the cell/ZrO2 interface. Hence in clinical practice UVC photofunctionalization could improve the soft tissue seal around dental implants functioning as a valid barrier between implant and peri-implant bone, thereby improving the long-term success of implants.