Effect of Surface Conditioning on the Bond Strength Between 3D-printed PMMA Denture Bases and Resin-based Artificial Teeth

Introduction This study aimed to evaluate the effect of different surface conditioning protocols on the Shear Bond Strength (SBS) between SLA-based 3D-printed PMMA denture base and resin-based artificial teeth. Methods Forty denture base specimens were fabricated using stereolithography-based 3D printing and allocated into four groups (n = 10): control (unpolymerized resin-only), bonding agent, monomer + sandblasting, and monomer-only. The teeth were attached to the denture base specimens with the base resin monomer. SBS was measured using a universal testing machine. Failure modes were classified, and surface topographies were examined by Scanning Electron Microscopy (SEM). Statistical analyses were performed using Welch’s one-way ANOVA with Games-Howell post-hoc tests and Pearson’s chi-square test (α = 0.05). Results Significant differences in SBS were observed among the surface conditioning protocols ( p < 0.001). The monomer-only group exhibited the highest SBS values, followed by the sandblasting + monomer group, the control group, and the bonding agent group. Mixed failures, defined as fractures occurring both at the tooth-denture base interface and within the material, were predominantly observed in the monomer-only and sandblasting + monomer groups, whereas adhesive failures were more frequent in the bonding agent group. SEM analysis revealed distinct qualitative surface morphologies associated with each conditioning protocol, including smoother surfaces in the control group and more porous and irregular surface structures after monomer application. Discussion The higher SBS values observed after monomer application may be associated with improved interaction between the denture base resin and artificial teeth. In addition, the qualitative SEM observations suggested that differences in surface morphologies may have contributed to variations in interfacial adhesion among the tested groups. Conclusion Monomer application demonstrated the highest bond strength values among the evaluated surface conditioning protocols for bonding resin-based artificial teeth to SLA-based 3D-printed PMMA denture base resin.