Improvement resin cement adhesion to zirconia ceramic surfaces using plasma polimerization tecniques

The purpose of this study was to evaluate the microshear bond strength of resin cement to zirconia ceramic surfaces with plasma polymerized thin film derived from organosilicon containing monomer.The study was performed using yttria stabilized zirconia (Y-TZP). Forty experimental Y-TZP plates approximately 10 mm in length, 5 mm in width and 1 mm in thickness were fabricated by copy milling technique. Each sample surface was metallographically polished with diamond paste and abraded with 600 grid SiC paper. 5 groups (n=8 in each group) of Y-TZP were samples randomly assigned according to the surface treatments applied which were as follows; Control group, No further treatment (Kontrol), Airborne particle abrasion with 50 ?m Al2O3 particles (KUM), Laboratory tribochemical silica coating with 30 ?m Al2O3 particles + silane coupling agent (ROC), Plasma polymerization (PP), Plasma etching (PA).Surface roughness and film thickness of samples were determined by using the atomic force microscope. Surface chemistry of coated specimens was characterized by X-ray photoelectron spectroscopy. Contact angle measurements were performed with sessile drop technique.All specimens were cemented with 10-methacryloyloxydecyldihydrogen-phosphate containing resin cement (Panavia F 2.0). Microshear bond strength tests were performed with a universal testing machine at a cross-head speed of 0.5 mm/min. The failure mode was also recorded by examining each specimen at x10 magnification using steromicroscope. The study design included multiple dependent variables therefore, a multivariate analysis of variance (MANOVA) test was performed (F=26.488, df=16, p=.000) Then, the differences in mean microshear bond strength values of each group were analyzed using One-way analysis of variance (ANOVA) followed by Post Hoc multiple comparisons.The average bond strengths and the standard deviations (mean±SD MPa) of the four experimental groups were as follows: KUM (7.92±1.6 MPa), ROC (9.25±2.12viiMPa), PP (8.13±1.58 MPa), PA (8.72±2.08MPa). All four experimental groups had higher microshear bond strength values than the control group (5.84±1.37 MPa), (p<.05). The post hoc test results showed that KUM, PP, and PA were not significantly different in terms of bond strength (p>.05). PP showed the lowest average surface roughness (10.2±3.23MPa). All four experimental groups were significantly different from each other and the control group related to surface roughness (p<.05) with one exception. The surface roughness values of the PA group revealed similar values with the control group specimens (p>.05). X-ray photoelectron spectroscopy data showed the presence of Si and chemical bonds in plasma polymerized thin film structure. The thickness of thin film was measured as 96 nm. Contact angle measurements showed all groups were significantly different from each other (p<.05) and the highest average hydrophilic surface character was obtained from the PA group (52.01±1.13MPa). Failure modes were predominantly (%83.3) adhesive.Keywords: Zirconia, surface coating, microshear test, atomic force microscopy, X-ray photoelectron spectroscopy