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

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°, 45°, and 90° orientations with a layer thickness of 100 μm. 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°, Armeara resin demonstrated the highest flexural strength, while Asiga resin exhibited superior elastic modulus at 45° and 90°. The 45° 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°, 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.