Effect of Air Abrasion Particle Size on Shear Bond Strength of Ultra-translucent Monolithic Zirconia after Artificial Aging: An In Vitro Study

Purpose: To explore the influence of air abrasion using alumina particles in two distinct sizes (50 and 110 μm) on the bonding strength and surface characteristics of ultra-translucent zirconia bonded to enamel. Materials and methods: Twenty-eight disk specimens were created from ultra-translucent, multilayered Katana zirconia using computer-aided design/computer-aided manufacturing (CAD/CAM) milling. The samples were divided into two groups, each containing 14 specimens (<i>n</i> = 14): group A, which was treated with 50 μm alumina particles, and group B, treated with 110 μm alumina particles. Surface roughness was evaluated using a profilometer after surface preparation. Prior to aging, scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDX) analyses were performed. To replicate approximately 15 years of intraoral use, the specimens were autoclaved for 5 hours at 134°C and 2 bars of pressure. Duo-Link Universal adhesive cement was used to bond the specimens to enamel. After artificial aging, shear bond strength tests were conducted along with SEM and EDX analyses. Fracture patterns were examined using a digital light microscope. Group comparisons were evaluated through the Mann–Whitney <i>U</i> test. Categorical variables were expressed as counts and percentages, with the Chi-squared test employed to analyze differences between groups. Results: The shear bond strength demonstrated no statistically significant difference between group A (15.03 ± 2.77 MPa) and group B (13.99 ± 2.76 MPa), as indicated by a <i>p</i>-value of 0.33. However, group A exhibited significantly lower surface roughness (0.93 ± 0.04 μm) compared to group B (0.96 ± 0.02 μm) (<i>p</i> = 0.03). SEM of the 50 μm zirconia specimen showed a small porous, irregular surface texture with small microretentive areas and defective crack areas, while EDX revealed a higher percentage of zirconium oxide concentration (ZrO₂). In contrast, the 110 μm zirconia specimen showed large porous, irregular surface texture with defective crack areas in SEM, and EDX revealed a higher percentage of other oxides. SEM of the debonded group A and group B specimens showed cement traces spreading homogeneously over the surface with detached areas. The predominant failure modes were mixed. Conclusion: Sandblasting with 50 μm alumina particles results in bond strength comparable to that achieved with 110 μm particles, with no significant difference in performance. Both particle sizes increase surface roughness and primarily produce mixed failure modes. How to cite this article: Abdultawab AM, Amin SA, Abdelaziz AN. Effect of Air Abrasion Particle Size on Shear Bond Strength of Ultra-translucent Monolithic Zirconia after Artificial Aging: An <i>In Vitro</i> Study. Int J Prosthodont Restor Dent 2024;14(4):208–217.