Optimization of Stereolithography Parameters to Improve Mechanical Properties of Dental Temporary Crowns Using Response Surface Methodology

This study optimizes and validates stereolithography (SLA) process parameters and assesses a thin posttreatment coating to enhance the mechanical properties and surface quality of resin-based dental temporary crowns using response surface methodology (RSM) and analysis of variance (ANOVA). Key parameters, including layer thickness, printing orientation, and bottom exposure time, were evaluated to determine their effects on dimensional accuracy, flexural strength, surface roughness, and material hardness, with the goal of improving the functionality and durability of SLA-fabricated temporary crowns. ANOVA was employed to assess the statistical significance of each parameter and their interactions. The optimization process determined that 90° printing orientation, 100 µm layer thickness, and 25 s bottom exposure time yielded the best results for untreated specimens, while treated specimens achieved optimal performance with a 90° printing orientation, 80.55 µm layer thickness, and 27.10 s bottom exposure time. Specimens printed using these optimized parameters exhibited superior mechanical properties compared to non-optimized experimental conditions. Material characterization (FTIR, SEM, EDS) corroborated these trends�higher conversion, a stiffer near-surface layer, and a deposited coating�consistent with the measured gains in strength and hardness. Furthermore, SLA-printed crowns fabricated using the optimized parameters were directly compared with commercially manufactured crowns, revealing that SLA-based crowns exhibited higher compressive strength and hardness, while posttreatment significantly improved surface smoothness. Although SLA-printed crowns still exhibited higher roughness than natural teeth, their customizability, superior mechanical performance, and enhanced post-processing adaptability suggest that SLA-based 3D printing is a promising alternative for producing high-performance temporary crowns with improved clinical viability. © ASM International 2025.