Effect of air-borne particle abrasion and tribochemical silica coating on surface characteristics, mechanical behavior, and bonding performance of 3D-printed resin-based materials

OBJECTIVES: This study evaluated how air-abrasion material, application time, and aging affect the surface characteristics, mechanical behavior, and bonding performance of three-dimensionally (3D) printed resin. METHODS: Specimens were treated with aluminum oxide (Al₂O₃) or tribochemical silica coating (SiO₂) for 5, 10, and 15 s (50 μm, 2 bar). Surface roughness (Ra), flexural strength, elastic modulus, and shear bond strength (SBS) were measured. Aging included 5,000 thermocycles. Data were analyzed using ANOVA and Tukey's test (α = 0.05). RESULTS: Roughness was significantly affected by the abrasive material, application time and their interaction (p < 0.001). Al₂O₃ produced a time-dependent increase in roughness, whereas SiO₂ remained stable across intervals. Flexural strength was significantly reduced in all treated groups relative to the untreated control (p < 0.001). Elastic modulus was affected by surface conditioning, while aging (p = 0.979) and interaction effects (p = 0.966) were not significant. SBS was significantly influenced by abrasive material and application time, but not by aging or interaction effects (p > 0.05). SiO₂ showed more stable bonding across time, while Al₂O₃ was time-dependent. CONCLUSION: Both surface-conditioning protocols improved bond strength. Tribochemical silica coating provided higher bond strength while more consistently preserving the mechanical properties of the printed resin, and a 10 s application was sufficient, as extending the treatment to 15 s provided no additional benefit under the conditions evaluated. Increased surface roughness did not necessarily result in improved bond strength. CLINICAL RELEVANCE: Tribochemical silica coating offers more predictable bonding outcomes for 3D-printed restorations, particularly when precise chairside application times cannot be guaranteed, thereby minimizing the risk of adhesive failure.