Effect of Air-Borne Particle Abrasion/Sintering Sequence on the Flexural Strength of Zirconia.

Abstract

INTRODUCTION:Zirconia represents a valuable material that combines both color acceptance and ability to withstand high loads. It had been reported that sintering of Zirconia followed by air-borne particle abrasion affect its strength. The effect of air-borne particle abrasion/sintering sequence on shear bond strength of resin cements to Zirconia was found non-significant; however the effect of sequence on the flexural strength has not been reported. The Ivoclare Vivadent manufacturer recommendation is to sinter the Zirconia before subjecting it to any air-borne particle abrasion. AIM OF THE STUDY: to evaluate the effect of air-borne particle abrasion/sintering sequence on the flexural strength of Zirconia. MATERIALS AND METHOD: forty bars of dimensions (26 × 6 × 1.5 millimeter) were fabricated from IPS e-max zircad. The total number of specimens was divided into two equal groups (A and B). The specimens of group A (AS) were subjected to air-borne particle abrasion followed by sintering. However specimens of group B (SA) were sintered before air-borne particle abrasion. Specimens of each group were subjected to X-Ray Diffraction to show monoclinic-tetragonal phases percentage. Three-point loading was applied to all specimens to measure the flexural strength using a Universal Testing Machine. RESULTS: At statistically significant level p ≤ 0.05. Group SA has showed significantly higher flexural strength compared to group AS. Airborne particle abraded surface of group SA showed the highest amount of monoclinic phase crystals after X-Ray Diffraction analysis. CONCLUSIONS: Air-borne particle abrasion/sintering sequence affects flexural strength of Zirconia. Air-borne particle abrasion surface treatment induces tetragonal to monoclinic phase transformation in fully sintered Zirconia.