Mechanical and esthetic properties of denture base resins in relation to thermocycling

Abstract

This study evaluated the shear bond strength (SBS), flexural strength, and color stability of three denture base resins (DBRs)-heat-polymerized (HEA), cold-polymerized (COL), and 3D-printed (TDP)-before and after thermocycling. SBS was evaluated after bonding COL to each DBR. Flexural strength was measured via three-point bending, and color stability with a colorimeter. Half of the specimens underwent 10,000 thermocycles to simulate aging. TDP (9.91 MPa) showed significantly lower SBS than HEA (14.85 MPa) and COL (15.76 MPa) before thermocycling (p < 0.001), but was comparable to HEA (6.89 vs. 7.17 MPa; p > 0.999) afterward. SBS decreased significantly in all groups post-thermocycling (p < 0.01). Thermocycling did not affect the flexural strength of HEA (p = 0.841) or COL (p = 0.434), but significantly reduced TDP's flexural strength (87.55 to 79.79 MPa; p = 0.002), which nevertheless remained significantly higher than those of HEA and COL (p < 0.001). TDP exhibited the highest color change ([Formula: see text]= 3.23), significantly greater than HEA (0.83; p < 0.001) and COL (1.94; p = 0.002), exceeding the perceptibility threshold. While 3D-printed DBRs exhibited comparable SBS and flexural strength to heat-polymerized DBRs after thermocycling, their esthetic durability remains limited under simulated aging.