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.