EFFECT OF DIFFERENT SURFACE TREATMENTS ON BONDING OF ULTRA- TRANSLUCENT ZIRCONIA

Abstract

Introduction: Introduction of ultra-translucent zirconia led to increase its indications for minimally invasive aesthetic restorations, therefore, it is important to test its adhesive potentiality. Objectives: Investigation of shear bond strength (SBS) of ultra-translucent zirconia to enamel after different surface treatments and examination of their effect on surface topography. Materials and methods: Thirty six ultra-translucent zirconia discs, (O5mm×3mm height) were divided into three groups (n=12): Control (C): as-sintered discs, Sandblasted discs (SB): discs were sandblasted by 110μm Al2O3 particles for 10 seconds, at 2.5 bar pressure, from 10mm distance, and Etched discs (ZE): discs were dipped into Zircos-E etching solution (BIO DEN CO, Korea) for thirty minutes in an ultrasonic cleaner. The surface topography of two randomly selected discs from each group were examined by scanning electron microscopy (SEM) for descriptive analysis, and the remaining discs were bonded to enamel surfaces of human central incisors for performing the SBS test. Statistical analysis of SBS results was done by Kruskal Wallis test and post hoc test with statistically significant results at (p < 0.05). Results: Morphological examination of (C) showed closely connected grains, (SB) showed a number of superficial irregularities, and shallow scratches, whereas (ZE) showed gross discontinuity of grain structure. The highest SBS value was recorded by (SB) (19.01±2.00 MPa) with insignificant difference from (ZE) (16.73± 2.13 MPa), and significant difference from (C) with the lowest SBS value (8.69±1.95 MPa). Conclusions: Etching of ultra-translucent zirconia using (Zircos-E) is a promising technique for improvement of resin bonding in comparison to control and sandblasted groups.