Abstract:

Objective  This study aims to evaluate the influence of hot chemical etching on short- and long-term shear bond strength (SBS) of zirconia to resin. Methods  Eighty zirconia ceramic slices were obtained and randomly divided into five groups based on the surface treatment to be applied—group A: H2SO4/(NH4)2SO4 hot solution etching + application of Clearfil; group B: HF/HNO3 hot solution etching + application of Clearfil; group C: H2SO4/HF/HNO3 hot solution etching + Clearfil; group D: alumina sandblasting + application of Clearfil; group E: tribochemical silica coating + application of silane coupling agent. Eighty composite cylinders were bonded to pretreated ceramic slices using a bis-GMA-based resin cement. Specimens in each group were divided into two fractions: the first half received 24 h water storage, and the second half re-ceived 40 d water storage. Then, SBS tests were conducted. Morphological analysis of sandblasted alumina and hot chemical-etched zirconia surfaces were performed by scanning electron microscopy(SEM). Results  Group E displayed the highest SBS before artificial aging, and no statistical difference was found among the other groups. After 40 d water storage, groups A, B, and E showed significantly higher SBS than groups C and D. SBS increased significantly after artificial aging in groups A and B. No significant variations were found before and after artificial aging in the other groups. Conclusion  The experi-mental hot chemical etching solution provides enhanced bonding for zirconia than sandblasting, and the bond strengths remain stable after artificial aging.

Key words: zirconia, surface treatment, acid etching, bonding, aging