Effect of Surface Treatments on the Bond Strength of 3D-Printed Composite Resin to Feldspathic Ceramic

Objective: To investigate the effect of various surface conditioning protocols on the shear bond strength between 3D-printed dental composite resin and feldspathic ceramic rods using Panavia V5 resin cement. Methods: 3D-printed composite resin discs were allocated into four groups based on surface treatment: (1) untreated control, (2) air abrasion, (3) hydrofluoric acid etching, and (4) combined air abrasion and hydrofluoric acid etching. All specimens were bonded to standardized Vita Mark II ceramic rods using Panavia V5 cement under a static load to ensure uniform cement thickness, followed by light curing using an LED unit at 1200 mW/cm2 for 20 s. After 24 h of water storage at 37 °C, shear bond strength was evaluated using a universal testing machine. Statistical analysis was performed using one-way ANOVA and Tukey’s post-hoc test (α = 0.05). Results: The combined treatment group demonstrated the highest mean bond strength (40.7 ± 11.5 MPa), followed by the hydrofluoric acid group (37.8 ± 9.3 MPa). Both groups exhibited significantly higher bond strength compared to the untreated control (p = 0.002 and p = 0.011, respectively), with no statistically significant difference between them (p = 0.887). The air abrasion-only group did not differ significantly from the untreated control (p = 0.570). Conclusions: Hydrofluoric acid etching, either alone or in combination with air abrasion, significantly enhances the shear bond strength between 3D-printed composite resin and feldspathic ceramic substrates. Air abrasion alone did not result in a significant improvement compared to the untreated condition.