Effects of printing orientation on the mechanical performance of 3D-printed PMMA resins

Abstract

Background This study aimed to evaluate the impact of printing orientation on the mechanical and physical properties of three different 3D-printed PMMA denture base resins. The null hypothesis was that printing orientation would not significantly influence flexural strength, maximum force, and elastic modulus of these resins. Methods Specimens were printed using DLP technology at 0 degrees, 45 degrees, and 90 degrees orientations with a layer thickness of 100 mu m. Three different resins (Asiga DentaBASE, Saremco DENTURETEC, and Armeara DENTURE) were tested. Maximum force, flexural strength and elastic modulus were measured using a universal testing machine in accordance with ISO 20795-1 standards. Statistical analyses were performed using the Kruskal-Wallis and Dunn's tests, with significance set at p < 0.05. Results Printing orientation significantly affected all mechanical properties (p < 0.05). At 0 degrees, Armeara resin demonstrated the highest flexural strength, while Asiga resin exhibited superior elastic modulus at 45 degrees and 90 degrees. The 45 degrees orientation generally resulted in lower values across most parameters. These findings rejected the null hypothesis, indicating that print orientation is a critical determinant of resin performance. Conclusion Print orientation plays a significant role in determining the mechanical behaviour of 3D-printed PMMA resins. Different orientations should be strategically chosen depending on the mechanical requirements of the intended application. Among the resins, Armeara excelled in flexural strength at 0 degrees, while Asiga performed best in stiffness at higher angles. Optimising print orientation and material selection can significantly enhance the mechanical properties and durability of 3D-printed PMMA denture bases, ultimately improving clinical outcomes and patient satisfaction.