Influência do ângulo de impressão nas propriedades mecânicas de diferentes resinas 3D utilizadas para base de próteses totais

Abstract

3D printing has become a prominent method for manufacturing denture bases due to its advantages; however, improving the mechanical properties of these materials remains challenging. This study evaluated the flexural strength and microhardness of four 3D-printed denture base resins (Cosmos Denture [CD], Smart Print Biodenture [SP], PriZma 3D Bio Denture [PZB], and Printax BB Base [PXBB]) under different printing angles (0º, 45º, and 90º) and aging conditions. A total of 240 rectangular samples were printed using a digital light processing printer, polished, and divided into experimental groups. Half of the samples underwent thermal aging (10,000 thermocycles). Flexural strength and microhardness were then tested, and statistical analyses were conducted (three-way ANOVA, P<0.05). The results revealed significant differences in flexural strength among resins, with PZB showing the highest values, followed by SP, CD, and PXBB (P<0.001). Printing orientation had no significant effect on most resins (P>0.05), except for CD, which displayed higher flexural strength at 0º compared to 45º and 90º (P<0.001). Aging reduced flexural strength in PZB and SP resins (P<0.001), but PZB still maintained the highest values. Microhardness results showed no significant influence of printing orientation (P=0.865). Resin type and thermocycling significantly affected microhardness (P<0.001), with PZB and PXBB demonstrating the highest values. Aging increased microhardness in all resins except PXBB, which showed no change (P=0.765). This study concluded that the mechanical properties of 3D-printed denture base resins are influenced by resin brand and aging conditions, with unique behaviors observed for flexural strength and microhardness. Printing orientation generally had no effect, except in one resin. Thermocycling decreased flexural strength in some resins while enhancing microhardness in most. These findings emphasize the importance of considering material-specific properties and aging effects in 3D-printed denture bases.