Physico-chemical and Mechanical Assessments of a New 3D Printed PMMA-Based Acrylic Denture Base Material

Three-dimensional (3D) printing is progressively being applied in the dental arena due to its time-saving potential and low cost, especially for the digital preparation of acrylic resin denture bases in the treatment of edentulism.

This study investigated the flexural strength, surface properties, water sorption, and solubility of a new poly (methyl methacrylate) (PMMA) resin denture base fabricated with a 3D printer (test group) and compared it with a conventional heat-cured resin (control group).

Sixty cuboid wax samples were prepared from two groups, with a thickness of 4 mm and dimensions of 10×80 mm. Then, half of the samples in each group were thermocycled to determine the strength, surface properties, water sorption, and solubility of the samples. Two-way ANOVA and independent t-test were used at a significance level of 0.05 after the normality of data in groups was tested with the Kolmogorov-Smirnov.

Based on the obtained results, the flexural strength was higher in heat-cured resins than in the resin fabricated with the 3D printer. However, the flexural strength values in both resins were clinically acceptable (65 MPa) based on ISO standards. There was no significant difference in the mean flexural strength in the presence or absence of thermal stress for both groups. The layered structure was observed in the samples fabricated with two groups. However, the layering structure disappeared in all cases after polishing. The layering structure had no differences in the presence or absence of thermal stress. Mass change over time was observed for all groups. In the water sorption phase, the mass increased rapidly in the first 7 days, and then the increase rate decreased until it reached an equilibrium on day 21. In the desorption phase, the mass decreased steadily in the first 7 days, and then reduction was continued until equilibrium was obtained on day 21 of the dewatering process.

The 3D printer samples had greater water sorption, and no differences were found between the solubility of 3D printer samples and heat-cured samples. Heat-cured resin exhibited enhanced water sorption after thermal cycling, and 3D-printed materials displayed no significant change.