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Background: Repeated fracture of the denture base is a common problem in prosthodontics, and it represents a nuisance and a time sink for the clinician. Therefore, the possibility of increasing repair strength using new reinforcement materials is of great interest to prosthodontists. Aim of the study: This study aimed to evaluate the effects of incorporation of zirconia nanoparticles (nano-ZrO2) on the flexural strength and impact strength of repaired polymethyl methacrylate (PMMA) denture bases. Materials and methods: One hundred eighty specimens of heat-polymerized acrylic resin were fabricated (90 for each test) and divided into three main groups: one control group (intact specimens) and two groups divided according to surface design (45° bevels and butt joints), in which specimens were prepared in pairs to create 2.5 mm gaps. Nano-ZrO2 was added to repair resin in 2.5 wt%, 5 wt%, and 7.5 wt% concentrations of acrylic powder. A three-point bending test was used to measure flexural strength, and a Charpy-type test was used to measure impact strength. Scanning electron microscopy was used to analyze the fracture surfaces and nano-ZrO2 distribution. The results were analyzed with a paired sample t-test and an unpaired t-test, with a P-value of ≤0.05 being significant. Results: Incorporation of nano-ZrO2 into the repair resin significantly increased flexural strength (P<0.05). The highest value was found in the bevel group reinforced with 7.5% nano-ZrO2, whereas the lowest value was found in the butt group reinforced with 2.5% nano-ZrO2. The impact strength values of all repaired groups were significantly lower than those of the control group (P<0.05). Among repaired groups, the higher impact strength value was seen in the butt group reinforced with 2.5% nano-ZrO2. The bevel joint demonstrated mainly cohesive failure, whereas the butt joint demonstrated mainly adhesive failure. Conclusion: Incorporation of nano-ZrO2 into the repair resin improved the flexural strength of repaired denture bases, whereas it decreased impact strength, especially with high nano-ZrO2 concentrations.

This study examines electroosmotic-driven fractional Jeffrey blood flow with aggregated ZrO2 nanoparticles through a permeable time-varying multi-stenotic inclined artery. Critical influences such as thermal radiation, metabolic heat generation, buoyancy effects, and electroosmotic forces are integrated with nanoparticle aggregation to analyze their impact on blood flow behavior. The Caputo fractional derivative is employed to account for blood’s viscoelastic memory effects. The electric potential within the electric double layer is modeled by solving the Poisson-Boltzmann equation. Analytical solutions to the governing equations, transformed into dimensionless form, are derived using Laplace and Hankel transforms and expressed via Lorenzo-Hartley and Robotonov-Hartley special functions. Results show that fractional parameters reduce blood velocity and temperature, while higher stenotic height and electroosmotic forces enhance velocity. Nanoparticle aggregation decreases velocity and wall shear stress but raises temperature and the heat transfer coefficient. Artificial neural networks are used to predict wall shear stress and heat transfer coefficient with exceptional accuracy, achieving over 99.9% in both testing and cross-validation. These findings contribute to advancements in medical applications, including nanoparticle-based drug delivery, magnetically guided devices, thermal therapies, and precision blood flow monitoring.

In this study, ZrO 2 nanoparticles were synthesized by the hydrothermal method using different precursors and mineralizers. X-ray diffraction revealed that the choice of synthesis components has a significant impact on the phase composition and crystallinity of the resulting ZrO 2 nanoparticles. Raman spectroscopy indicated that varying the combinations of precursors and mineralizers enables the formation of both cubic and tetragonal phases of ZrO 2 within the samples. Transmission electron microscopy showed that the particle size ranges from 4 to 14 nm, with crystalline samples predominantly containing particles in the 5–6 nm range. In amorphous samples, nuclei with sizes between 5 and 10 nm were observed. TGA analysis demonstrated that all samples contain a substantial amount of synthesis by-products, reaching up to 30% of the total mass. Spectroscopic analysis of the optical properties determined that samples with more than 9% by-product content exhibit the highest absorption in the UV subrange. The phase stability of ZrO 2 nanoparticles and the effect of temperature on the crystallization of amorphous samples were estimated using high-temperature X-ray diffraction.

Due to the low mechanical performances of 3D-printed denture base resins, ZrO2 nanoparticles (ZrO2NPs) were incorporated into different 3D-printed resins and their effects on the flexure strength, elastic modulus, impact strength, hardness, and surface roughness were evaluated. A total of 286 specimens were fabricated in dimensions per respective test and divided according to materials into three groups: heat-polymerized as a control group and two 3D-printed resins (NextDent and ASIGA) which were modified with 0.5 wt.%, 1 wt.%, 3 wt.%, and 5 wt.% ZrO2NPs. The flexure strength and elastic modulus, impact strength, hardness, and surface roughness (µm) were measured using the three-point bending test, Charpy’s impact test, Vickers hardness test, and a profilometer, respectively. The data were analyzed by ANOVA and Tukey’s post hoc test (α = 0.05). The results showed that, in comparison to heat-polymerized resin, the unmodified 3D-printed resins showed a significant decrease in all tested properties (p < 0.001) except surface roughness (p = 0.11). In between 3D-printed resins, the addition of ZrO2NPs to 3D-printed resins showed a significant increase in flexure strength, impact strength, and hardness (p < 0.05) while showing no significant differences in surface roughness and elastic modulus (p > 0.05). Our study demonstrated that the unmodified 3D-printed resins showed inferior mechanical behavior when compared with heat-polymerized acrylic resin while the addition of ZrO2NPs improved the properties of 3D-printed resins. Therefore, the introduced 3D-printable nanocomposite denture-base resins are suitable for clinical use.

Polytetrafluoroethylene (PTFE) is a polymeric material with excellent self-lubricating properties. In this study, in order to improve the wear resistance of PTFE, the PTFE matrix was filled with soft-phase polyetheretherketone (PEEK) particles and hard-phase nano-ZrO2 particles in varying volume ratios. A linear reciprocating friction tester was used to test the tribological properties of the PTFE composites. Optical microscopy (OM) and scanning electron microscopy (SEM) were utilized to observe the formation and evolution of the transfer film on the surface of the counterpart metal during the friction process. Molecular dynamics simulation software (Materials Studio MS) was used to simulate and analyze the frictional behavior between the molecular structures of PTFE composites and the counterpart iron atoms on a microscopic scale. The results showed that the uniformity and firmness of the transfer film had an important influence on the wear resistance of the material. PEEK and ZrO2 nanoparticles were able to improve the firmness and formation rate of the transfer film, respectively, resulting in significant improvement in the wear resistance of PTFE (volume wear rate reduced from 7.7 × 10−4 mm3/Nm for pure PTFE to 1.76 × 10−6 mm3/Nm for nano-ZrO2/PEEK/PTFE). Molecular dynamics simulations revealed that the poor wear resistance of PTFE was due to significant interlayer slippage within its molecular chains. PEEK molecular chains could effectively adsorb PTFE molecular chains and formed a strong bond. ZrO2 nanoparticles also contributed to the overall stability of the PTFE matrix. Both soft and hard fillers significantly inhibited interlayer slippage between PTFE molecular chains, enhancing the shear deformation resistance of the material and thus improving the wear resistance of PTFE composites.

Over more than half a century of using zirconia in technology and industry, researchers have faced several challenges related to the performance of this material. It is believed that some issues regarding the low performance of the zirconia ceramics can be solved by using a multidoping strategy. In this study, nanoparticles with the composition (1 − x)⸱ZrO2 − x⸱MD (where MD—multi-dopant Y:Ce:Mg:Ca with cation relationship 1:1:1:1 and x = 0.05–0.25 mol. %) were synthesized using a hydrothermal method followed by annealing. XRD and Raman spectroscopy analyses demonstrated that in the concentration range of x = 0.10–0.25 mol.%, the only detectable phase in the synthesized samples was the tetragonal phase of zirconia. SEM analysis revealed that the size of the final particles ranged from 20 to 50 nm. It was demonstrated that using obtained nanoparticles as precursors for sintering leads to the formation of multiphase ceramics. The microhardness and biaxial flexural strength of the ceramic samples vary depending on the dopant concentration in the range of 600–1400 HV and 25–200 MPa respectively. Mechanical properties mostly depend on porosity and grain size in the sintered material. The study shows that the multidoping strategy has high potential to obtain new constructional ceramics and components for solid oxide fuel cells.

Statement of problem The 3D-printed denture base resin needed reinforcement. Purpose To evaluate the effects of adding nano ZrO2 and nano TiO2 on microbial colonization and patient satisfaction with 3D-printed maxillary complete dentures. Materials and methods Twenty-four patients who needed complete dentures were randomly distributed into three equal groups. Group I: Patients used maxillary complete dentures 3D printed without the addition of any additives. Group II: Patients used maxillary complete dentures 3D after reinforcement by Nano-ZrO 2 (0.4%) by weight. Group III: Patients used maxillary complete dentures 3D printed after reinforcement by Nano-TiO 2 (0.4%) by weight. For microbial evaluation, a cotton swab was taken from the mucosa of the palate and the intaglio surface of maxillary dentures, and microbial colonization was evaluated by calculating the number of colony-forming units of S. aureus on mannitol salt agar plates and C. albicans on Sabouraud’s dextrose agar plates after 48 h of incubation at insertion, 6 months, 12 months and 18 months. Patient satisfaction was evaluated 15 days after insertion and at 6, 12, and 18 months. The values of microbial colonization and patient satisfaction were analyzed via repeated-measures ANOVA followed by Tukey’s multiple comparison test. Results No significant differences in microbial colonization were detected among the three groups concerning Staphylococcus aureus in the palatal mucosa. There was a significant difference between Group I, the lowest antimicrobial group, and the other groups, while between Groups II and III, there was no significant difference in the number of S. aureus on the fitting surface of the denture. There were significant differences between Group II, the highest antifungal group, and the other groups at 12 and 18 months concerning Candida albicans in the palate and in the dentures. There was a significant difference in patient satisfaction between Group I, the lowest, and the other groups, whereas there was no significant difference between Groups II and III. Conclusion Compared with the other groups, the nano-ZrO 2 group presented greater antimicrobial effects until 18 months, whereas the nano-TiO2 group presented antibacterial effects until 18 months and antifungal effects until 6 months. The addition of nano-ZrO 2 and nano-TiO 2 to 3D-printed denture base resin improved the aesthetic, speech, masticatory efficiency, hygiene, and comfort of patients. Trial registration The trial was registered in the Clinical Trials Registry under the number NCT06921577 on 10/04/2025 (retrospective registration).

Poly(methyl methacrylate) (PMMA) is a commonly used material, as it is biocompatible and relatively cheap. However, its mechanical properties and weak antibiofilm activity are major concerns. With the development of new technology, 3D-printed resins are emerging as replacements for PMMA. Few studies have investigated the antibiofilm activity of 3D-printed resins. Therefore, this study aimed to investigate the antibiofilm activity and surface roughness of a 3D-printed denture base resin modified with different concentrations of zirconium dioxide nanoparticles (ZrO2 NPs). A total of 60 resin disc specimens (15 × 2 mm) were fabricated and divided into six groups (n = 10). The groups comprised a heat-polymerized resin (PMMA) group, an unmodified 3D-printed resin (NextDent) group, and four 3D-printed resin groups that were modified with ZrO2 NPs at various concentrations (0.5 wt%, 1 wt%, 3 wt%, and 5 wt%). All specimens were polished using a conventional method and then placed in a thermocycler machine for 5000 cycles. Surface roughness (Ra, µm) was measured using a non-contact profilometer. The adhesion of Candida albicans (C. albicans) was measured using a fungal adhesion assay that consisted of a colony forming unit assay and a cell proliferation assay. The data were analyzed using Shapiro–Wilk and Kruskal–Wallis tests. A Mann–Whitney U test was used for pairwise comparison, and p-values of less than 0.05 were considered statistically significant. The lowest Ra value (0.88 ± 0.087 µm) was recorded for the PMMA group. In comparison to the PMMA group, the 3% ZrO2 NPs 3D-printed group showed a significant increase in Ra (p < 0.025). For the 3D-printed resins, significant differences were found between the groups with 0% vs. 3% ZrO2 NPs and 3% vs. 5% ZrO2 NPs (p < 0.025). The highest Ra value (0.96 ± 0.06 µm) was recorded for the 3% ZrO2 NPs group, and the lowest Ra values (0.91 ± 0.03 µm) were recorded for the 0.5% and 5% ZrO2 NPs groups. In terms of antifungal activity, the cell proliferation assay showed a significant decrease in the C. albicans count for the 0.5% ZrO2 NPs group when compared with PMMA and all other groups of 3D-printed resins. The group with the lowest concentration of ZrO2 NPs (0.5%) showed the lowest level of C. albicans adhesion of all the tested groups and showed the lowest Candida count (0.29 ± 0.03). The addition of ZrO2 NPs in low concentrations did not affect the surface roughness of the 3D-printed resins. These 3D-printed resins with low concentrations of nanocomposites could be used as possible materials for the prevention and treatment of denture stomatitis, due to their antibiofilm activities.

To improve the wear resistance of the surface of the cotton picker spindle, a Ni-Co-ZrO2 composite coating with different ZrO2 nanoparticle concentrations was prepared using electrodeposition technology on the micro surface of spindle hook teeth, and the morphologies of the surface and cross-section, element contents, grain sizes, microhardness and friction coefficients of the Ni-Co-ZrO2 composite coating were obtained; a simulated wear test was conducted based on the independently developed spindle hook tooth wear device, and the morphologies and elemental distributions of the composite coating before and after wear were obtained; the effects of different ZrO2 nanoparticle concentrations (0, 2, 4, 6, 8 g/L) on the morphology, element content, grain size, microhardness, friction coefficient and wear resistance of the coating were discussed. The test results indicated that compared with Ni-Co coatings, Ni-Co-ZrO2 composite coatings featured a more compact coating structure, a greater coating thickness, and a smaller grain size. The presence of ZrO2 nanoparticles led to further improvement of the coating’s microhardness, friction coefficient and wear resistance. When the mass concentration of ZrO2 nanoparticles reached 4 g/L, the microhardness of Ni-Co-ZrO2 composite coating reached the maximum value, 545.4 Hv0.1, and the friction coefficient decreased to 0.06. At the same time, in the simulated wear test, the composite coating with this concentration had the smallest wear area and the highest wear resistance.

This study presents the synthesis, characterization, and application of magnetic magnetite–zirconium dioxide (Fe3O4–ZrO2) nanoparticles as an efficient nanoadsorbent for fluoride removal from water. The nanoparticles were synthesized using a wet chemical co-precipitation method with Fe/Zr molar ratios of 1:1, 1:2, and 1:4, and characterized using Fourier-transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM), X-ray diffraction (XRD), and energy-dispersive X-ray spectroscopy (EDS). FTIR analysis confirmed the presence of Fe3O4 and ZrO2 functional groups, while XRD showed that increased Zr content led to a dominant amorphous phase. SEM and EDS analyses revealed quasi-spherical and elongated morphologies with uniform elemental distribution, maintaining the designed Fe/Zr ratios. Preliminary adsorption tests identified the Fe/Zr = 1:1 (M1) nanoadsorbent as the most effective due to its high surface homogeneity and optimal fluoride-binding characteristics. Adsorption experiments demonstrated that the material achieved a maximum fluoride adsorption capacity of 70.4 mg/g at pH 3, with the adsorption process best fitting the Temkin isotherm model (R2 = 0.987), suggesting strong adsorbate–adsorbent interactions. pH-dependent studies confirmed that adsorption efficiency decreased at higher pH values due to electrostatic repulsion and competition with hydroxyl ions. Competitive ion experiments revealed that common anions such as nitrate, chloride, and sulfate had negligible effects on fluoride adsorption, whereas bicarbonate, carbonate, and phosphate reduced removal efficiency due to their strong interactions with active adsorption sites. The Fe3O4–ZrO2 nanoadsorbent exhibited excellent magnetic properties, facilitating rapid and efficient separation using an external magnetic field, making it a promising candidate for practical water treatment applications.