Purpose: This in vitro study evaluated the flexural strength, impact strength, hardness, and surface roughness of 3D-printed denture base resin subjected to thermal cycling treatment. Materials and Methods: According to ISO 20795-1:2013 standards, 120 acrylic resin specimens (40/flexural strength test, 40/impact strength, and 40/surface roughness and hardness test, n = 10) were fabricated and distributed into two groups: heatpolymerized; (Major.Base.20) as control and 3D-printed (NextDent) as experimental group. Half of the specimens of each group were subjected to 10,000 thermal cycles of 5 to 55°C simulating 1 year of clinical use. Flexural strength (MPa), impact strength (KJ/m 2 ), hardness (VHN), and surface roughness (μm) were measured using universal testing machine, Charpy's impact tester, Vickers hardness tester, and profilometer, respectively. Data were analyzed by ANOVA and Tukey honestly significant difference (HSD) test (α = 0.05). Results:The values of flexural strength (MPa) were 86.63 ± 1.0 and 69.15 ± 0.88; impact strength (KJ/m 2 )-6.32 ± 0.50 and 2.44 ± 0.31; hardness (VHN)-41.63 ± 2.03 and 34.62 ± 2.1; and surface roughness (μm)-0.18 ± 0.01 and 0.12 ± 0.02 for heat-polymerized and 3D-printed denture base materials, respectively. Significant differences in all tested properties were recorded between heat-polymerized and 3D-printed denture base materials (P < 0.001). Thermal cycling significantly lowered the flexural strength (63.93 ± 1.54 MPa), impact strength (2.40 ± 0.35 KJ/m 2 ), and hardness (30.17 ± 1.38 VHN) of 3D-printed resin in comparison to thermal cycled heat-polymerized resin, but surface roughness showed non-significant difference (p = 0.262). Conclusion: 3D-printed resin had inferior flexural strength, impact strength, and hardness values than heat-polymerized resin, but showed superior surface roughness. Temperature changes (thermal cycling) significantly reduced the hardness and flexural strength and increased surface roughness, but did not affect the impact strength.

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Increased occlusocervical thickness and decreased cantilever length allowed the cantilever to withstand higher loads. The occlusocervical thicknesses and cantilever lengths of zirconia frameworks tested withstood the maximum reported occlusal force. The properties of components in the implant-abutment framework assembly should be considered in the interpretation of these results.

This study aimed to evaluate the water sorption, solubility, and translucency of 3D-printed denture base resins (NextDent, FormLabs, and Asiga), compare them to heat-polymerized acrylic denture base resins, and assess their performance under the effects of thermal cycling. A total of 80 acrylic disc specimens were used in the current study, categorized into four groups (n = 10); in one group, the samples were fabricated conventionally with a heat-polymerizing process (control), while the other three groups were fabricated digitally from different 3D-printed reins (NextDent, FormLabs, and Asiga). Specimens were fabricated according to the manufacturers’ recommendations and immersed in distilled water for 48 h at 37 °C. Data on water sorption, solubility, and translucency measurements (T1) were obtained. All the specimens were subjected to 5000 thermal cycles, and then the measures were repeated using the same method (T2). Data analysis was attained via ANOVA and the post hoc Tukey test (α = 0.05). The type of resin significantly affected the values of water sorption, solubility, and translucency (p < 0.001). The water sorption of 3D-printed resins was increased significantly in comparison to control with or without a thermal cycling effect. In terms of solubility, a significant increase in 3D-printed resins before thermocycling was observed; however, after thermocycling, Asiga had a significantly low value compared to the other groups (p < 0.001). Thermal cycling increased the water sorption and solubility of all tested materials. In comparison to control, the translucency of the 3D-printed resins was significantly decreased (p < 0.001). The translucency was significantly decreased per material in terms of the thermal cycling effect (before and after). NextDent showed significantly low translucency values (p < 0.001) compared to the other groups. All 3D-printed resin groups had higher water sorption and solubility and lower translucency values in comparison to the heat-polymerized resin group. Regardless of resin types, thermal cycling adversely affected all tested properties.

WHO estimates that the global number of tobacco users exceeds 1.3 billion people. Few studies have examined the effect of locally made smokeless tobacco (ST) products on the color changes of material used in dental prosthetics. Bearing the recent advances in CAD/CAM ceramic restorations material in mind, this study aimed to assess ST influence on mean color change (∆E*) values among selected CAD/CAM ceramic types: multilayer zirconia (Ceramill Zolid PS), zirconia-reinforced lithium silicate ceramic (Vita Suprinity), and feldspathic (Vita TriLuxe) restorative materials. The color changes of the ceramics were compared to VITA classical and VITA 3D-MASTER shade guides. Sixty CAD/CAM ceramic specimens (20 samples each) were fabricated from Ceramill Zolid PS, Vita TriLuxe Forte, and VITA Suprinity. Specimens were prepared and divided into two groups according to the ST type and immersed for two weeks. Basic VITA classical and VITA 3D-MASTER colors were recorded at a baseline of one week and two weeks. The highest ∆E* values were recorded in the black ST for Vita Suprinity (4.77) in the first week, followed by Vita TriLuxe (4.07) in the second week. For white ST, Vita TriLuxe (4.87), and Vita Suprinity (4.42) showed extensive color change after two weeks and one week, respectively. The color change was least in zirconia for black and white ST after one week. CAD/CAM ceramic materials showed no significant difference after 1 and 2 weeks for the tested ST types. The effects of ST on CAD/CAM ceramic material (∆E* values) were high but did not reach clinically unacceptable values. Zirconia showed the least amount of color change among all the tested materials.