Sol–gel derived bioactive coating on zirconia: Effect on flexural strength and cell proliferation

Abstract

The purpose of this study was to evaluate the effect of sol-gel derived bioactive coatings on the biaxial flexural strength and fibroblast proliferation of zirconia, aimed to be used as an implant abutment material. Yttrium stabilized zirconia disc-shaped specimens were cut, ground, sintered, and finally cleansed ultrasonically in each of acetone and ethanol for 5 minutes. Three experimental groups (n = 15) were fabricated, zirconia with sol-gel derived titania (TiO ) coating, zirconia with sol-gel derived zirconia (ZrO ) coating, and non-coated zirconia as a control. The surfaces of the specimens were analyzed through images taken using a scanning electron microscope (SEM), and a non-contact tapping mode atomic force microscope (AFM) was used to record the surface topography and roughness of the coated specimens. Biaxial flexural strength values were determined using the piston-on-three ball technique. Human gingival fibroblast proliferation on the surface of the specimens was evaluated using AlamarBlue assay™. Data were analyzed using a one-way analysis of variance (ANOVA) followed by Tukey's post-hoc test. Additionally, the biaxial flexural strength data was also statistically analyzed with the Weibull distribution. The biaxial flexural strength of zirconia specimens was unaffected (p > 0.05). Weibull modulus of TiO coated and ZrO coated groups (5.7 and 5.4, respectively) were lower than the control (8.0). Specimens coated with ZrO showed significantly lower fibroblast proliferation compared to other groups (p < 0.05). In conclusion, sol-gel derived coatings have no influence on the flexural strength of zirconia. ZrO coated specimens showed significantly lower cell proliferation after 12 days than TiO coated or non-coated control. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 105B: 2401-2407, 2017.

TiO2Coating and UV Photofunctionalization Enhance Blood Coagulation on Zirconia Surfaces

“…The potential biological benefits of sol-gel derived TiO 2 coatings on zirconia have been previously demonstrated by the authors [10]. TiO 2 coatings improved fibroblast proliferation and the coating procedure did not affect the favorable mechanical properties of zirconia.…”

“…In the case of oral implants, one important success criterion is the bond and attachment between the implant abutment and the surrounding soft tissue [1, 5–10]. The formation of this permucosal seal protects the peri-implant environment by separating it from the intraoral environment, thereby blocking the passage of bacteria that can cause peri-implantitis [1, 10]. The formation of this soft tissue bond is highly dependent on the initial interactions of the abutment with blood [11, 12].…”

“…Sol-gel derived nanoporous titania (TiO 2 ) coatings are one example of these surface treatments. Nanoporous TiO 2 coatings are shown to improve soft tissue reaction with titanium and have also been deposited on different surfaces, including zirconia [9, 10, 17–19]. Furthermore, ultraviolet (UV) irradiation of TiO 2 coatings has been shown to create an amphiphilic and a super-hydrophilic surface that is believed to be beneficial for its bioactivity [20].…”

TiO2 Nanocoatings with Controllable Crystal Type and Nanoscale Topography on Zirconia Implants to Accelerate Bone Formation

“…While these methods work well for titanium implants, in zirconia implants, these modifications leave the implant surface bioinert and without nanoscale structure, making it inferior to the titanium implant surface. Thus, several approaches, such as sol-gel and plasma spraying, have been used to generate a TiO 2 layer on the zirconia surface to create a surface similar to the surface of a titanium implant [ 17 – 19 ]. Nevertheless, the TiO 2 coatings fabricated by these conventional surface coating methods are usually of microscale thickness and bond to zirconia surfaces physically, so it is difficult to form a continuous and uniform coating on complex microstructured zirconia surfaces, leading to a high risk of failure at the bone-implant interface.…”

Zirconia implants with improved attachment to the gingival tissue

“…The potentials of these coatings to optimize zirconia for better softtissue attachment have been previously demonstrated by the authors where the coatings enhanced fibroblast proliferation and induced a faster blood coagulation. 21,22 Furthermore, in vivo studies with experimental animals using sol-gel derived TiO 2 coatings on titanium substrates have shown good epithelial attachment, decreased gingival inflammation and less marginal bone loss upon histological examination. [21][22][23][24][25][26] Consequently, the aim of this study was to evaluate the attachment of gingival tissue on zirconia implant and zirconia provided with sol-gel derived nanostructured coating.…”