Recent evidence suggests that nano-TiO₂ particles improve antimicrobial and physical properties when incorporated into dental prosthetic materials. However, there exists a paucity of information regarding their impact on material properties when the prosthetic materials are 3D-printed over time. The purpose of this study was to evaluate the time-dependent printability and surface property changes occurring in a 3D-printed denture base resin containing nano-titanium dioxide (TiO₂) particles. A 0.4 wt% concentration of 30 nm rutile TiO₂ nanoparticles was ultrasonically dispersed into a denture base resin. Disks were printed weekly using a Form 2 SLA printer until printing failed. Printability, surface roughness (R_a), color difference (ΔE_ab), and translucency parameters were measured across timepoints. Surface roughness was assessed via profilometry, while color and translucency were evaluated using a spectrophotometer under standardized conditions. Print failure occurred at week 8, beyond which the resin could no longer reliably produce full specimens. R_a roughness decreased from 3.83 µm to 0.48 µm, which denoted a significant time-dependent decrease (ρ = −0.733, p = 0.016). Color difference with the unmodified control declined from 26.32 to 17.13 ΔE_ab units (ρ = −0.976, p < 0.001). All printed samples exceeded the clinically acceptable thresholds for both R_a (0.2 µm) and ΔE_ab (<3.7). Although the printability of the resin–TiO2 mixture was maintained for 7 weeks, mixture homogeneity declined over time. TiO₂ additions to a denture polymer produced significant changes in surface roughness and color that were not clinically acceptable. Results from this study illustrate the time dependence required for retaining surface properties in 3D-printed dentures containing nano-TiO₂.

Background: Fabricating clear aligners by thermoforming three‐dimensional printed dental models requires a high degree of accuracy. It is unknown whether model thickness affects the accuracy when used to thermoform aligners.Purpose: This research utilizes three‐dimensional printed models made with differing wall thicknesses to determine its effect on their ability to withstand deformation during aligner fabrication.Methods: A total of 50 models of different wall thickness (10 each of 0.5, 1.0, 1.5, 2.0 mm, and solid) were printed using model resin (Model V2, Formlabs) on a low‐force stereolithography printer (Form 3B, Formlabs). Aligners were then fabricated using a thermal pressure forming machine (Biostar V, Great Lakes Dental Technologies) utilizing 25 s cycles to adapt 0.030″ acrylic sheets (Invisacryl, Great Lakes Dental Technologies), then removed from the models and sprayed with a contrast powder (Optispray, Dentsply Sirona) to aid in scanning with an intraoral scanner (CEREC Primescan, Dentsply Sirona). Each aligner's data was then compared to the original file used for printing with 3D comparison software (Geomagic Control X, 3D Systems).Results: The results show model thickness greater than or equal to 2.0 mm produced clinically acceptable results within the margin of error (0.3 mm). A total of 0.5 mm thickness failed to withstand thermal forming in 4 of the 10 trials. A total of 0.5 mm produced 27.56% of results in tolerance, 1.0 mm produced 75.66% of results in tolerance, 1.5 mm had 80.38% of results in tolerance, 86.82% of 2 mm models were in tolerance, and solid had 96.45% of results in tolerance.Conclusion: Hollow models of thicknesses 2.0 mm and solid models produced clinically acceptable aligners while utilizing less resin per unit compared to solid models, thus being more cost effective, time efficient and eco‐friendly. Therefore, a recommendation can be made to print hollow models with a shell thickness of greater than 2.0 mm for aligner fabrication.

Objectives: This study sought to understand the effects of print orientation on a novel 3D‐printing technology recently made available for the fabrication of dentures.Material and Methods: A total of 90 experimental samples (30 each at 0, 45, and 90 degrees) were printed using denture resin on a polyjet printer. The milled control samples (n = 10) were milled on a 5‐axis dental laboratory mill from a denture base disc. 96 samples were tested for flexural strength and extension at break using a 3‐point bend test on a universal testing machine. The data were analyzed using statistical software and evaluated for statistical significance using general linear models with a Dunnett test with α = 0.05.Results: The results showed that the flexural strength and extension at break were both affected by print orientation with the 90‐degree orientation being the lowest performing group for both properties. The 0‐degree and 45‐degree orientations both exceeded the ISO minimum flexural strength of 65 MPa, with mean flexural strengths of 88.18 and 73.53 MPa. The 90‐degree group mean was well below the standard at 28.12 MPa. The milled sample group mean was 65.18 MPa. Extension at break showed similar results with less variation in the printed groups. Mean extension at break of the milled samples group was 15.05 mm, the 0‐degree was 5.99 mm, 45‐degree was 4.72 mm, and 90‐degree was 1.92 mm.Conclusion: Flexural strength and extension at break were influenced by print orientation. A 0‐degree, or horizontal, print orientation yielded the highest values for flexural strength. The milled samples had significantly higher values for extension at break, but similar values for flexural strength.

Recent studies have shown that astronauts experience altered immune response behavior during spaceflight, resulting in heightened susceptibility to illness. Resources and resupply shuttles will become scarcer with longer duration spaceflight, limiting access to potentially necessary medical treatment and facilities. Thus, there is a need for preventative health countermeasures that can exploit in situ resource utilization technologies during spaceflight, such as additive manufacturing (i.e., 3D printing). The purpose of the current study was to test and validate recyclable antimicrobial materials compatible with additive manufacturing. Antimicrobial poly(lactic acid)- and polyurethane-based materials compatible with 3D printing were assessed for antimicrobial, mechanical, and chemical characteristics before and after one closed-loop recycling cycle. Our results show high biocidal efficacy (>90%) of both poly(lactic acid) and polyurethane materials while retaining efficacy post recycling, except for recycled-state polyurethane which dropped from 98.91% to 0% efficacy post 1-year accelerated aging. Significant differences in tensile and compression characteristics were observed post recycling, although no significant changes to functional chemical groups were found. Proof-of-concept medical devices developed show the potential for the on-demand manufacturing and recyclability of typically single-use medical devices using antimicrobial materials that could serve as preventative health countermeasures for immunocompromised populations, such as astronauts during spaceflight.