Effect of Surface Treatment of Zirconia on the Shear Bond Strength and Debonding Time: An In Vitro Study

Purpose: To evaluate the effects of different zirconia surface treatments on shear bond strength to dentin and the time required for debonding.Materials and methods: A total of 120 extracted human third molars were prepared and mounted in acrylic blocks.Experimental zirconia rods were fabricated and finished according to standardized protocols.The specimens were divided into four groups based on surface treatment: (A) air particle abrasion alone, (B) air particle abrasion plus phosphoric acid methacrylate-based primer, (C) air particle abrasion plus 10-methacryloyloxydecyl dihydrogen phosphate (MDP)-based primer, and (D) laser etching with Er, Cr:YSGG waterlase.All rods were cemented to dentin using a dual-cure adhesive resin cement.Shear bond strength and debonding time were measured using a universal testing machine.Data were analyzed using one-way analysis of variance (ANOVA) and Tukey's honestly significant difference (HSD) post hoc test (p ≤ 0.05).Results: Significant differences were observed among the groups for both shear bond strength and debonding time (p < 0.05).Group C (air particle abrasion + MDP-based primer) exhibited the highest shear bond strength (48.93 ± 6.27 MPa) and longest debonding time (16.63 ± 3.36 seconds).Group D (laser etching) showed the lowest values for both parameters (9.67 ± 2.94 MPa, 9.40 ± 1.25 seconds).Conclusion: Air particle abrasion followed by MDP-based primer application provides effective surface treatment for enhancing zirconia-dentin bond strength and durability.Micromechanical and chemical conditioning protocols for optimal zirconia-resin adhesion in clinical practice are advised.