The Effect of Curing Time on the Impact Strength of Resin Denture Bases Made by 3D Printing Techniques

Advances in additive manufacturing have enabled the fabrication of denture bases using three-dimensional (3D) printing technology; however, the mechanical properties of the resulting materials, particularly impact strength, are highly influenced by post-processing parameters such as curing time. This experimental laboratory study aimed to evaluate the effect of different curing time variations on the impact strength of 3D-printed denture base resin and to compare its performance with that of heat-polymerized acrylic resin (HPAR). A post-test only control group design was employed, in which specimens were divided into four groups consisting of 3D-printed resin with curing times of 4.5, 5.0, and 5.5 seconds, and a control group fabricated from HPAR. The results demonstrated that the 3D-printed resin cured for 5.0 seconds exhibited the highest mean impact strength (1.56 ± 0.14 kJ/m²), followed by the 4.5-second group (1.47 ± 0.09 kJ/m²), while the lowest value was observed in the 5.5-second curing group (1.28 ± 0.23 kJ/m²). In contrast, the HPAR group showed substantially higher impact strength than all 3D-printed resin groups, with a mean value of 2.99 ± 0.97 kJ/m². These findings indicate that curing time optimization significantly affects the impact strength of 3D-printed denture base resin; nevertheless, heat-polymerized acrylic resin remains superior in terms of mechanical toughness for denture base applications