Comparison of mechanical properties of different 3D printing technologies

This study evaluated and compared the mechanical properties of provisional 3D-printed polymers fabricated using three commonly used 3D printing technologies: stereolithography (SLA), digital light processing (DLP), and liquid crystal display (LCD). Ninety specimens, both bar-shaped and disc-shaped, were printed using standardized resin color and print settings for each technology. Flexural strength was measured using a universal testing machine, while surface hardness and roughness were evaluated using a micro-Vickers hardness tester and atomic force microscopy, respectively. Statistical analyses were performed using one-way ANOVA and Tukey's post-hoc tests at a significance level of p < 0.05. SLA demonstrated the highest flexural strength (93.39 ± 5.57 MPa), significantly higher than DLP (69.97 ± 8.48 MPa) and LCD (64.69 ± 8.98 MPa). Surface hardness was comparable across SLA (18.80 ± 0.57 kgf/mm²), DLP (17.80 ± 1.85 kgf/mm²), and LCD (18.27 ± 0.93 kgf/mm²). In terms of surface roughness, SLA showed the lowest mean value (14.79 ± 7.96 nm), followed by DLP (24.59 ± 9.76 nm), and LCD exhibited the highest roughness (89.87 ± 28.26 nm). The findings indicate that SLA produces polymers with superior flexural strength and the smoothest surface finish, making it preferable for applications requiring strong, high-quality surfaces, while DLP and LCD provide alternative benefits in specific use cases.