Abstract Background This study aimed to evaluate the impact of artificial aging on the surface integrity, mechanical properties, and thermal stability of three commercially available denture base materials: conventional heat-polymerized polymethyl methacrylate (PMMA), CAD/CAM-milled PMMA, and 3D-printed photopolymerizable resin. Methods Cylindrical samples (6 mm diameter × 3 mm height) were fabricated for each material. All samples were finished, and measurements were performed on the finished flat surface. A total of 20 samples were prepared for each material; half were tested at baseline and half after artificial aging, yielding a final sample size of n = 10 per group. Artificial aging was performed using 5000 thermocycles between 5 °C and 55 °C with a 10-second dwell time. Surface roughness (mean Ra, µm) was measured using non-contact optical profilometry, while surface microhardness (mean Vickers hardness, HV) was assessed using the Vickers hardness test. Thermal stability was evaluated using thermogravimetric analysis (TGA; mass loss, %) and differential scanning calorimetry (DSC; heat flow, mW/mg). Surface morphology was examined through scanning electron microscopy (SEM). Results Results indicated a significant increase in surface roughness for all materials post-aging ( p < 0.05), with 3D-printed resin showing the greatest change (0.04 → 0.07 μm) and milled PMMA the least (0.04→0.06 μm). Milled PMMA had the highest baseline hardness (20.01 HV) and exhibited the least reduction after aging, while 3D-printed resin experienced the most pronounced decline (16.96→16.21 HV). TGA showed mass gain in conventional PMMA (+ 0.23%) and 3D-printed resin (+ 0.13%), whereas milled PMMA lost mass (-0.16%). Conclusions Overall, CAD/CAM-milled PMMA demonstrated superior thermal aging resistance, maintaining hardness and surface quality, followed by conventional PMMA. In contrast, 3D-printed resin was most vulnerable to surface deterioration and softening under artificial aging. CAD/CAM-milled PMMA can be a recommended choice for the denture base.
Elazzouni et al. (Tue,) studied this question.