Bionic Microstructure Effect On 3D Printed Zirconia-Resin Bond Strength

This study explores the impact of bionic microstructures on the bond strength of additively manufactured (AM) zirconia. Finite element analysis (FEA) assessed the influence of microstructure dimensions (diameter: 100–200 µm, depth: 25–100 µm, spacing: 100–200 µm) on mechanical bond strength (S). The ultimate forming capabilities of microstructures on stereolithography (SLA) zirconia were also explored. A total of 88 zirconia specimens were prepared, including 66 standard samples and 22 with bionic microstructures (MS) (200 µm diameter, 100 µm depth, 200 µm spacing). Standard specimens underwent three abrasion treatments (n=22): non-alumina abrasion (NAB), 50 µm alumina abrasion (50AB) and 110 µm alumina abrasion (110AB). Surface roughness (Ra), contact angle (CA) and surface morphology were analyzed. Specimens were divided into non-MDP (NMDP) and MDP (MDP) subgroups (n=10). Shear bond strength (SBS) and failure type were analyzed 24h after bonded. FEA indicated that diameter, depth, and spacing influenced S, and a design with a diameter of 200 µm achieved better S when the spacing is 200 µm. MS exhibited the highest Ra and lowest CA. Without MDP, MS showed significantly higher SBS (P<0.001). With MDP, group MS achieved slightly higher SBS than group 50AB (P=0.009) and significantly higher than other groups (P<0.001). Within MS, SBS was higher in the subgroup MDP than NMDP (P<0.001). Bionic microstructures enhance bond strength, achieving or surpassing alumina abrasion effects. Combining microstructures with MDP further improves bonding performance.