Change of phase transformation and bond strength of Y-TZP with various hydrofluoric acid etching

Abstract

Objectives The purpose of this study was to quantify phase transformation after hydrofluoric acid (HF) etching at various concentrations on the surface of yttria-stabilized tetragonal zirconia polycrystal (Y-TZP), and to evaluate changes in bonding strength before and after thermal cycling. Materials and Methods A group whose Y-TZP surface was treated with tribochemical silica abrasion (TS) was used as the control. Y-TZP specimens from each experimental group were etched with 5%, 10%, 20%, and 40% HF solutions at room temperature for 10 minutes. First, to quantify the phase transformation, Y-TZP specimens ( n = 5) treated with TS, 5%, 10%, 20% and 40% HF solutions were subjected to X-ray diffraction. Second, to evaluate the change in bond strength before and after thermal cycling, zirconia primer and MDP-containing resin cement were sequentially applied to the Y-TZP specimen. After 5,000 thermal cycles for half of the Y-TZP specimens, shear bond strength was measured for all experimental groups ( n = 10). Results The monoclinic phase content in the 40% HF-treated group was higher than that of the 5%, 10%, and 20% HF-treated groups, but lower than that of TS-treated group ( p < 0.05). The 40% HF-treated group showed significantly higher bonding strength than the TS, 5%, and 10% HF-treated groups, even after thermal cycling ( p < 0.05). Conclusions Through this experiment, the group treated with SiO 2 containing air-borne abrasion on the Y-TZP surface showed higher phase transformation and higher reduction in bonding strength after thermal cycling compared to the group treated with high concentration HF.

Effect of surface topography and wettability on shear bond strength of Y-TZP ceramic

“…Finally, the tetragonal-to-monoclinic ( t – m ) phase transformation, which is a critical consideration for the surface treatment of Y-TZP ceramics, was not evaluated in this study. Previous studies demonstrated that gentle air abrasion protocols, as used in this study, generally trigger t – m phase transformation 42 – 44 , whereas HF etching with conditions close to the current study was found to induce phase transformation to the lesser degree than air abrasion 45 . Nevertheless, such a small amount of monoclinic phase presented on the zirconia surfaces prior to the bonding procedure was found to not influence the resin bond strength 45 – 47 .…”

“…After aging, the increase in monoclinic contents 48 and the decrease in bond strengths of resin-zirconia 45 , 49 , 50 were widely reported. However, the study revealing the negative correlation between monoclinic contents and bond strengths after aging is scarce.…”

Enhanced osteogenic activity of titania-modified zirconia implant by ultraviolet irradiation

“…Several strategies have been employed to enhance the bioactivity of zirconia ( Cengiz et al, 2016 ), such as sandblasting ( Moritz et al, 2019 ), acid etching ( Yu et al, 2021 ) and diverse bioactive coatings comprising silica, zinc and various compounds ( Ke et al, 2017 ). These approaches can create a biologically active surface on zirconia implants.…”

Surface property changes observed in zirconia during etching with high-concentration hydrofluoric acid over various immersion times

“…In most studies concerning zirconia etching with an HF solution, etching has occurred only for a relatively short time of 5 to 10 min 12,16) . This practice seems to be derived from the etching time associated with the use of lowconcentration HF for conventional ceramic materials.…”

“…Although there have been studies 16,17) exploring the effect of zirconia surface roughness and phase transformation on bond strength using various concentrations of HF and at diverse temperatures, few have specifically studied the changes in the physical properties of the zirconia surface depending on the application time of HF etching. This study aims to investigate the changes in the degree of phase transformation, surface roughness and bonding strength when the zirconia surface is immersed in the high concentration (40%) and room temperature of the HF solution for various times and find the optimal immersion time.…”