Surface analysis and shear bond strength of zirconia on resin cements after non-thermal plasma treatment and/or primer application for metallic alloys

Abstract

There is no established protocol for bonding zirconia (Y-TZP) with resin cements. Non-thermal plasma (NTP) may be an alternative for the clinical problems related to adhesion. The purpose of the present study was to characterize the surface of Y-TZP exposed to methane (CH) NTP or coated with a layer of primer for metal alloys and the association between the two methods and to evaluate the effect of NTP treatment on bond strength between Y-TZP and two resin cements. A total of 235 Y-TZP discs (8×2mm) were distributed into five groups: Co (no surface treatment), Pr (primer), NTP (methane plasma), Pr+NTP and NTP+Pr. The effect of the treatment type on the surface free energy, morphology, topography and chemical composition of the Y-TZP discs was investigated. The discs were cemented to composite resin substrates using Panavia F2.0 or RelyX U200. Shear bond strength (n=10) analyses were performed (1mm/min) before and after thermocycling (5-55°C, 2000cycles) on the bonded specimens. The data were analyzed with one and three-way ANOVAs and Bonferroni tests (α=0.05). NTP reduced the surface energy and roughness of the Y-TZP discs. SEM-EDS and XPS analyses showed the presence of the organic thin film, which significantly improved the bond strength results when Rely X U200 was used, whereas the primer treatment was more effective with Panavia F2.0. Thermocycling significantly reduced the bond strength results of the NTP and Pr+NTP groups cemented with Rely X U200 and the Pr and NTP+Pr groups cemented with Panavia F2.0. Nonthermal plasma improves the bond strength between Rely X U200 and Y-TZP and also seems to have water-resistant behavior, whereas Panavia F2.0 showed better results when associated with primer.

Effect of Non-Thermal Atmospheric Pressure Plasma (NTP) and Zirconia Primer Treatment on Shear Bond Strength between Y-TZP and Resin Cement

“…As a result of this study, there was no statistically significant difference in SE values of each group ( p > 0.05), and the NTP treatment before primer application did not affect the change of SE (Pr: 57.98, NTP + Pr: 58.56, p > 0.05). This is similar to the results of another study [ 47 ]. All groups had the primers applied at the last step, so it is supposed that similar surface energy appeared for all groups.…”

Non-thermal plasma increase bond strength of zirconia to a resin cement

“…Recent studies have been reported increase bond strength values between resin cement and zirconia after NTP treatment, although when Ar gas was used [20,24,26,27]. Conversely, the gas used in this study is O 2 .…”

“…Surface energy of a material can be measured by evaluating the contact angle of liquids and their ability to spread on a certain surface [21]. This method measures the values of dispersive and polar components of SE, clarifying the molecular interactions such as dipole-dipole, hydrogen bond and dispersive forces of London [24,26]. Furthermore, enhancing the surface energy results in better wettability, which is key for bonding [21,36].…”

“…The distance from the tip, as well as the position of the samples, and the zirconia surface was kept constant form all assays. The relationship of the contact angle and surface energy was calculated by the Owens-Wendt-Rabel-Kaelble method, which calculates the contact angle between drops of two liquids with different polarities and the Y-TZP surface [24,31].…”

“…Such a surface treatment is capable of transforming non-reactive surfaces into reactive ones without affecting their mechanical properties [20]. In this way, plasma application enhances surface energy (SE) and wettability of substrates [17,18,[20][21][22][23][24][25], improving the adhesion of the treated surface to Rely X U200 [23], Panavia F 2.0 [23], Rely X Unicem [26] and Clearfil Esthetic [27] resin cements.…”