Three-dimensional (3D) printing is increasingly used for denture base fabrication, but printer-dependent processing may alter the properties of the same resin. This in vitro study compared Lucitone Digital Print 3D Denture Base resin fabricated with two manufacturer-validated systems: Carbon M2 (continuous liquid interface production) and Asiga MAX UV (digital light processing) (n = 10 per printer per outcome). After standardized cleaning, post-curing, and 7 days of water storage at 37 ± 1 °C, flexural strength, fracture toughness, fracture work, Vickers hardness, and surface roughness were evaluated. Asiga specimens showed significantly higher flexural strength (83.5 ± 2.0 vs. 76.9 ± 1.2 MPa; p < 0.0001), fracture work (1853 ± 330 vs. 1452 ± 295 J/m 2 ; p = 0.010), and Vickers hardness (12.5 ± 0.7 vs. 11.4 ± 0.6 kg/mm 2 ; p = 0.007). Fracture toughness, expressed as Kmax, did not differ significantly between Carbon and Asiga specimens (2.91 ± 0.36 vs. 2.75 ± 0.27 MPa·m^0.5; p = 0.287), nor did surface roughness (1.72 ± 0.24 vs. 2.13 ± 0.84 µm; p = 0.283). Thus, the printer system influenced selected mechanical properties of an identical denture-base resin, highlighting the importance of considering the complete resin–printer–post-processing system when interpreting material performance.
The biological response to coating-derived components is an important consideration in the preliminary development of functionalized titanium implants. In the present study, an Elumbotti ( Ormocarpum cochinchinense )-derived composite coating was applied to titanium cortical screws (12 mm), and its preliminary in vitro biological response was investigated using a cell-free protein-denaturation assay and MG-63 osteoblast-like cells. Uncoated titanium (T1) and Elumbotti-coated titanium cortical screw samples (ST1) were included in the experimental evaluation. Bovine serum albumin (BSA) protein-denaturation inhibition was assessed as a preliminary cell-free measure of protein-stabilizing activity, with diclofenac sodium used as the reference standard. MG-63 cellular responses were evaluated using MTT viability, scratch-wound closure, and acridine orange/ethidium bromide (AO/EtBr) fluorescence staining assays. The MTT assay evaluated concentration-dependent responses to the ST1 test preparation, whereas the scratch-wound and AO/EtBr assays evaluated cellular responses following exposure to conditioned medium obtained from ST1-coated titanium cortical screws. ST1 demonstrated greater BSA protein-denaturation inhibitory activity than T1, with calculated IC 50 values of 63.032 and 118.379 µg/mL, respectively. In the MTT assay, MG-63 viability showed a concentration-dependent response to the ST1 test preparation, remaining above 70% at concentrations up to 32 µg/mL and decreasing below 70% at concentrations of 64 µg/mL and above. Scratch-wound closure following exposure to ST1-conditioned medium increased from 67.07% at 24 h to 83.45% at 48 h, compared with 27.24% and 34.50%, respectively, in untreated control cells. AO/EtBr staining demonstrated time-dependent changes in cell viability and membrane integrity following prolonged exposure to ST1-conditioned medium. Overall, the findings provide preliminary evidence of concentration- and time-dependent biological responses associated with the Elumbotti-derived coating system and its soluble components. However, the present assays do not establish direct cell–coating interactions, cellular anti-inflammatory activity, osteogenic differentiation, osseointegration, or improved orthopedic implant performance. Further batch-specific physicochemical characterization, direct cell–surface studies, coating stability and release analyses, osteogenic and inflammatory-marker evaluation, and in vivo investigation are required to establish the biological and functional relevance of the coating for orthopedic applications.
This study aimed to evaluate the biomechanical effects of different posterior support strategies in borderline atrophic mandibular full-arch implant rehabilitation, where treatment decision-making remains challenging, using three-dimensional finite element analysis (FEA). A totally edentulous mandibular model was generated, featuring severe residual ridge atrophy posterior to the mental foramen, with barely sufficient bone height to accommodate extra-short implants superior to the inferior alveolar nerve. Three different implant configurations were analyzed: Model 1 consisted of axial implants combined with distal extra-short implants; Model 2 represented the conventional All-on-4 concept with tilted posterior implants; and Model 3 combined tilted posterior implants with distal extra-short implant support. Cortical and trabecular principal stresses, von Mises stresses in implant and prosthetic components, and prosthesis displacement values were evaluated under bilateral posterior loading. Model 2 demonstrated the highest stress concentrations and prosthesis displacement values in both peri-implant bone and prosthetic components. Cortical maximum principal stress values ranged between 6.54 and 9.85 MPa, while implant von Mises stresses ranged from 24.04 to 68.75 MPa. Prosthesis displacement values were highest in Model 2 (0.0273 mm). In contrast, Model 3 exhibited more homogeneous stress distribution and lower stress accumulation in cortical bone, trabecular bone, implants, abutments, and framework structures. Prosthesis displacement values in Model 3 (0.0053 mm) were comparable to Model 1 and substantially lower than those observed in Model 2The combination of tilted posterior implants with distal extra-short implant support demonstrated a more homogeneous stress distribution and lower prosthetic deformation under the simulated loading condition. These findings suggest that increasing posterior support may contribute to more favorable load distribution in borderline atrophic mandibular models.
Acute ultraviolet B (UVB) exposure induces epidermal hyperplasia, pigmentation-related responses, and early extracellular matrix remodeling. Topical tyrosinase inhibitors, including arbutin and kojic acid, can have limited residence on damaged skin. Here, we evaluated a skin-conformal composite patch comprising aligned polyurethane nanofiber membranes integrated with methacrylated hyaluronic acid (MHA) hydrogel arrays loaded with arbutin or kojic acid. Seven-week-old Hairless Mouse, Strain 2 (HRM2) mice were assigned to six groups: control (CTL), UVB only (UV), UVB plus topical arbutin (UVA), UVB plus topical kojic acid (UVK), UVB plus arbutin-loaded MHA patch (UV-A-MHA), and UVB plus kojic acid-loaded MHA patch (UV-K-MHA). Dorsal skin received a single UVB dose (200 mJ/cm 2 ), was treated immediately, and was analyzed on Day 4. Drug-loaded MHA patch treatment attenuated UVB-induced epidermal thickening and was associated with qualitative differences in dermal matrix organization, while direct comparisons with the corresponding freely applied formulations varied across endpoints. These histological findings were evaluated using hematoxylin and eosin, Masson’s trichrome, Picro-Sirius Red, and Fontana-Masson staining. GFP-loaded MHA hydrogels remained detectable in the epidermis and upper dermis through Day 4, supporting local cargo retention under skin-contact conditions. Preliminary HPLC-UV analysis detected arbutin and kojic acid parent peaks in MHA formulations before and after 60 s of UV exposure. Patch treatment was associated with significant reductions in α-smooth muscle actin and vimentin, whereas effects on SMAD phosphorylation differed between the two drug formulations, without detectable changes in body weight or serum TNF-α and IL-6. Because the main experiment lacked drug-free MHA patch and bandage-only controls, scaffold-, occlusion-, and drug-specific effects could not be fully separated. These findings support aligned nanofiber-supported MHA hydrogel arrays as functional biomaterial patches for localized cutaneous delivery and modulation of acute UVB-induced remodeling-associated responses.
Silk fibroin is a highly promising biomaterial for wound dressings; however, its lack of inherent antibacterial activity limits broader clinical adoption. In this study, robust antibacterial properties were successfully conferred onto electrospun silk fibroin nanofiber mats using a mussel-inspired polydopamine (PDA) dip-coating strategy. Primary dip-coating deposited a uniform PDA nanolayer that served as an adhesive scaffold, enabling subsequent anchoring of dopamine nanoparticles during secondary coating. This hierarchical structure markedly increased surface roughness and reactive catechol density. Antibacterial evaluation against Staphylococcus aureus showed that secondary PDA-coated mats substantially reduced bacterial colonization relative to both primary-coated and unmodified controls. Secondary coating cycles further enhanced antibacterial performance. Cytocompatibility assessment performed according to ISO 10993-5 confirmed excellent biocompatibility of the modified mats, with no significant cytotoxicity observed. This simple, versatile, and antibiotic-free functionalization approach significantly improves the translational potential of silk fibroin nanofibers as next-generation antibacterial wound dressings.
