Impact strength of 3D printed and conventional heat-cured and cold-cured denture base acrylics

To evaluate and compare the impact strength of 3D-printed resin to conventionally fabricated denture bases of heat-cured and cold-cured acrylic resin.

Denture base materials were evenly divided into three groups (n = 25 each; N = 75): (1) 3Dprinted material (Denture Base LP, Formlabs); (2) Heat-cured acrylic resin (Lucitone 199, Dentsply Sirona); and (3) cold-cured acrylic resin (Lucitone HIPA, Dentsply Sirona). The 3Dprinted specimens were designed through computer-aided design (CAD) software (Autodesk Meshmixer) with the dimensions 64 mm long, 12.7 mm wide, and 3.2 mm thick, then printed with a desktop stereolithography printer (Form 2, Formlabs). Heat-cured and cold-cured acrylic resin specimens were fabricated through conventional (compression and pouring) methods. The impact energy was read directly from the impact tester in joules, and the cross-sectional area of each specimen was used to calculate the impact strength in kJ/m². Analysis of variance, Tukey multiple comparisons test, and a likelihood ratio α = .05 were conducted.

The average mean impact strength was 8.9 kJ/m² for heat-cured acrylic resin, 11.2 kJ/m² for 3D-printed resin, and 14.9 kJ/m² for cold-cured acrylic resin. Tukey multiple comparisons test showed that the impact strength for the cold-cured group was significantly greater than the 3D-printed resin and heat-cured acrylic resin groups.

Within the limitations of this study, the cold-cured acrylic (Lucitone HIPA) showed the greatest impact strength, followed by 3D-printed resin (Denture Base LP) and conventional heat-cured denture base materials (Lucitone 199), respectively.