Effect of sandblasting on Shear Bond Strength of 3D Printed Denture Base to conventional and Milled Denture Teeth

Purpose This study evaluated the effect of sandblasting on the shear bond strength (SBS) of three-dimensional (3D) printed denture base resin bonded to both conventional and milled artificial teeth. Materials and methods Forty-eight specimens were divided according to the application of sandblasting to fitting surface of experimental teeth into 3 main equal groups, Group A: 16 specimens without sandblasting. Group B: 16 specimens with sandblasting using 50 μm aluminum oxide Al₂O₃, Group C: 16 specimens with sandblasting using 250 μm Al₂O₃, each main group was subdivided according to the type of artificial teeth into two equal subgroups, 8 specimens for each. All teeth were vertically aligned and bonded to a cylindrical base of three dimensional(3D) printed denture base resin. The SBS of specimen was measured at a cross-head speed of 1 mm/min until debonding. Data were statistically analyzed using two-way ANOVA, one-way ANOVA with Bonferroni post-hoc, and Student’s t-tests. Failure modes were analyzed using Chi-square and Monte Carlo tests ( P ≤ 0.05). Results Both sandblasting and tooth type significantly influenced SBS ( p < 0.001), with sandblasting showing a dominant effect (Partial η² = 0.981). Milled teeth demonstrated superior bonding compared to conventional teeth across all groups ( p < 0.001). SBS values increased proportionally with Al₂O₃, Al2O3 particle size (Group A < B < C), with the highest SBS recorded for milled teeth in Group C (1.514 ± 0.029 MPa). Furthermore, a significant shift in failure modes was observed ( p < 0.001). Conclusion Within the limitations of this in-vitro study, it can be concluded that increasing sandblasting intensity significantly enhances the bond strength of denture bases. 3D printed denture base with milled teeth provide significantly better interfacial integrity and higher SBS compared to conventional acrylic teeth.