Which low-fusing porcelain glaze treatment technique is better to promote a vitreous surface on Y-TZP ceramic?

OBJECTIVE: to evaluated the influence of two types of low-fusing porcelain glaze application on the surface of a zirconia ceramics stabilized by yttrium (Y-TZP).METHODS: Y-TZP specimens were divided into five groups (n=5) according the surface treatments: control (CO), no treatment was performed; application of a thin low-fusing porcelain glass layer by the powder/liquid technique (GPL); GPL followed by 10% hydrofluoric acid (HF) etching (GPL-HF); glaze spray application (GS); GS followed by 10% HF etching (GS-HF). Roughness measurements contact angle, x-ray diffraction, energy-dispersive spectroscopy (EDS) and scanning electron microscope (SEM) analysis were performed.RESULTS: ANOVA and Tukey tests revealed that GPL had significantly lower contact angle values than the other groups (GPL:50.31º; GPL-HF: 72.73º; GS-HF: 81.73º; CO: 96.48º; GS:101.30º; p=0.001). GPL-HF presented a significant higher roughness (Ra/Rq: 2658.0/3367.0 ηm; p=0.001) than the other groups (GPL: 872.1/1162.0 ηm; GS-HF: 383.0/603.6 ηm; GS: 303.4/391.3 ηm; CO:263.4/339.1 ηm). The X-ray diffraction analysis just tetragonal phase in all groups. EDS and SEM analysis show a highest amount of silica on GPL and GPL-HF surface.CONCLUSION: the application of the low-fusing porcelain glaze by the powder/liquid technique followed by the HF etching promoted a better surface to micromechanical and chemical adhesion.