Journal of Functional Biomaterials最新文献

Background and objectives: Provisional restorations are essential in fixed prosthodontics, ensuring esthetics, function, and biological protection during treatment. Recent advances in CAD/CAM technologies have enabled the fabrication of provisional materials with enhanced color stability and fracture resistance compared to conventional chairside polymeric materials. This study aimed to compare the color stability and fracture strength of provisional crowns fabricated using CAD/CAM and a conventional direct chairside technique.

Materials and methods: A total of 40 provisional crowns (four materials, n = 10 each group) were fabricated for a mandibular molar 3.6 using two workflows: CAD/CAM-milled poly(methyl methacrylate) (PMMA), high-impact polymer composite (HIPC; Bredent), and Ambarino composite (Creamet), and directly fabricated 3M™ Protemp™ (Scutan technique), respectively. Color stability was evaluated after seven-day immersion in coffee and red wine at 37 °C using a spectrophotometer (CIE L*a*b* system). Fracture resistance (F_max) was measured under axial load in a universal testing machine. Data were analyzed by one-way ANOVA and Tukey's HSD (α = 0.05).

Results: Significant differences were observed among materials (F(3,36) = 212.6, p < 0.001). HIPC showed the highest mean fracture resistance (2068.9 ± 104.0 N), followed by PMMA (1215.8 ± 61.4 N) and 3M™ Protemp™ (1183.4 ± 86.4 N), while Ambarino exhibited the lowest (555.4 ± 25.4 N). Regarding color stability, Ambarino demonstrated the smallest ΔE* (1.1 ± 0.2), followed by PMMA (2.0 ± 0.3), HIPC (2.8 ± 0.3), and Protemp™ (4.9 ± 0.4). Only Protemp™ exceeded the clinical perceptibility threshold (ΔE* > 3.3).

Conclusions: Both manufacturing methods and material compositions significantly influence the optical and mechanical properties of provisional restorations. CAD/CAM-milled HIPC and PMMA provided superior fracture strength and clinically acceptable color stability, suggesting their suitability for long-term or high-load temporary crowns compared with chairside-fabricated composites, particularly in posterior regions.

Background/objectives: Endothelial cells play a key role in peripheral nerve regeneration, forming aligned vasculature which bridges the gap in the injured nerve tissue and guides the regrowing tissue. This work aimed to mimic key features of this aligned vasculature by differentiating endothelial cells from human induced pluripotent stem cells (hiPSCs) and incorporating them into engineered neural tissue (EngNT).

Methods: hiPSCs were differentiated into endothelial cells with the temporal addition of growth factors and biomolecules. These hiPSC-derived endothelial cells (hiPSC-ECs) were incorporated into EngNT fabricated from collagen hydrogels using the gel aspiration-ejection (GAE) technique and maintained in vitro to allow endothelial network formation.

Results: At the mRNA and protein level, pluripotency marker expression decreased and endothelial cell marker expression increased over the course of hiPSC differentiation to endothelial cells. The derived endothelial cells expressed CD31, CD144, ENG, VEGFR2, and VWF, and formed network structures in the matrix tubulogenesis assay. hiPSC-ECs incorporated into EngNT were viable and aligned. They formed highly aligned tube-like structures containing lumens after four days in culture and the EngNT constructs supported neurite growth in vitro when co-cultured with rat dorsal root ganglion (DRG) neurons.

Conclusions: This work rapidly generated engineered nerve tissue containing highly aligned endothelial tube-like structures, resembling key features of the early nerve regeneration bridge. Therefore, this 3D engineered tissue provides a platform to study the effects of endothelial cell structures in nerve repair treatment and translational development.

Clear aligners have gained popularity in orthodontics due to their aesthetics, comfort, and removability; however, their prolonged intraoral wear and frequent removal-reinsertion cycles create favorable conditions for microbial colonization. This in vitro study evaluated the efficacy of seven commercially available mouthwash formulations in inhibiting biofilms of Streptococcus mutans, Streptococcus oralis, and Candida albicans formed on four different clear aligner materials. Standardized aligner fragments were incubated for 24 h with microbial suspensions to allow biofilm formation, treated for 1 min with one of the mouthwashes, and then assessed for residual viability through spectrophotometric optical density measurements after a further 24 h incubation. Biofilm inhibition varied according to both mouthwash composition and aligner material. The chlorhexidine-based rinse (MW-D) consistently showed the highest inhibition across microorganisms, while the fluoride-cetylpyridinium chloride rinse (MW-B) performed strongly for S. oralis and C. albicans. An essential oil-based formulation with xylitol (MW-G) showed notable antifungal activity against C. albicans. Monolayer polyurethane aligners generally achieved higher inhibition rates than multilayer or copolyester-based materials. These findings indicate that antimicrobial efficacy on aligners depends on both mouthwash type and material, supporting a tailored approach to biofilm management in clear aligner therapy to reduce the risk of caries, periodontal disease, and candidiasis.

Alginate and chitosan (Ag/Cs) combined form an effective platform to develop biocompatible hydrogels with customizable properties for controlled drug release. Cannabidiol (CBD), a hydrophobic compound with anti-inflammatory and antibacterial effects, represents a powerful strategy to enhance their therapeutic performance. A/Cs hydrogels were produced using the CELLINK^® printer with 12 and 24 mg/mL of CBD. SEM and FTIR were assessed. Viscoelasticity was assessed using oscillatory rheology. Structural strength was evaluated via uniaxial compression. Swelling and absorption were measured gravimetrically under physiological conditions. CBD was successfully incorporated into the 3D-printed A/Cs hydrogel. Increasing the CBD concentration led to mechanical changes such as a dose-dependent decrease in G' and a slight reduction in the linearity threshold (typically 10-30% from medium loads), while still maintaining G' > G″. FTIR showed shifts in O-H/N-H and C=O, indicating hydrogen bonding without new reactive bands. Microscopic images revealed moderate pore compaction and increased tortuosity with dose. At higher CBD concentrations, the hydrogel resisted compression but could deform further before failure. Equilibrium swelling and absorption kinetics decreased with increasing dose, resulting in a reduced initial burst and lower water uptake capacity. The CBD-loaded hydrogel provides a mechanically suitable and molecularly stable platform for local drug release in the oral cavity.

Mg-based alloys are one of the most promising materials used in regenerative medicine for bone tissue engineering. Considering the increasing prevalence of a continuously aging population, as well as the high incidence of accidents and bone cancers, it is crucial to explore biomaterials that can serve as bone substitutes. After carefully analyzing the literature in the introduction section, we proposed two Mg-based alloys as suitable for obtaining biodegradable structures for bone defect treatment. To achieve trustworthy results, the alloys' microstructure was investigated using microscopic techniques coupled with energy-dispersive spectroscopy and X-ray diffraction. The obtained results were comparable with those described in references on similar Mg alloys. Then, the mechanical compression properties were highlighted, and the in vitro corrosion behavior proved that Mg-Zn exhibited a reduced corrosion rate compared to the Mg-Nd alloy, as tested using electrochemical methods. However, the in vivo tests showed good biocompatibility for both magnesium alloys. In conclusion, both alloys are suitable for use as potential bone substitute applications, but it must be taken into consideration that Mg-Zn alloys present lower biodegradation and mechanical properties. For future investigations, we aim to develop bone substitutes made from these materials, specifically designed for small bone defect treatment and with patient-adapted geometry. Due to the differences mentioned above, various designs will be tested.

Narrow-diameter implants (≤3.5 mm) have garnered significant attention due to their widespread application in areas with insufficient bone volume. However, their mechanical performance is limited. The cervical region, serving as a pivotal stress concentration zone, exhibits a thread form that directly modulates stress distribution and determines the long-term stability of the implant-bone interface. This study was designed to investigate the influence of varying thread forms and face angles on microstrain and stress distribution patterns in narrow-diameter implants (NDIs) and their adjacent cortical bone structures. Through systematic modification of implant thread forms and face angle parameters, finite element analysis (FEA) was employed to develop nine distinct implant models featuring varied geometric characteristics. Each model was implanted into Type III bone tissue, followed by the application of a 100 N occlusal force, including a vertical load and an oblique load deviated 30 degrees lingually from the long axis of the implants. Subsequent biomechanical evaluation quantified peak von Mises stress concentrations at the bone-implant interface, maximum equivalent elastic strain distributions in peri-implant bone tissue, and abutment stress profile characteristics. The results indicated that in the RB thread group, the optimal thread face angle parameter was 60 degrees; in the B thread group, this optimal thread face angle parameter was 45 degrees, whereas in the V thread group, the optimal thread face angle parameter was 30 degrees.

Zirconia is widely used for customized implant abutments owing to its esthetics, strength, and biocompatibility; however, the optimal surface modification for soft-tissue sealing and bone metabolic remains uncertain. This study evaluated how glass-ceramic spray deposition (GCSD), with or without handheld nonthermal plasma (HNP), alters zirconia surface physiochemistry and cellular responses. Field-emission scanning electron microscopy/energy-dispersive X-ray spectroscopy, surface roughness (Ra), wettability, and surface free energy (SFE) were measured. Human osteoblast-like cells (MG-63) and human gingival fibroblasts (HGF-1) were used to assess attachment and spreading, metabolic activity, cytotoxicity, and inflammatory response (tumor necrosis factor-α, TNF-α) (α = 0.05). GCSD produced an interlaced rod- and needle-like glass-ceramic layer, significantly increasing Ra and hydrophilicity. HNP further reduced surface contaminants, increased SFE, and enhanced wettability. The combination of GCSD and HNP yielded the greatest attachment and spreading for both cell types, without increases in cytotoxicity or TNF-α. GCSD with HNP creates a hydrophilic, micro-textured, chemically activated zirconia surface that maintains biocompatibility while promoting early attachment and bone metabolic activity, supporting its application for zirconia implant abutments.

This study evaluated the optical and mechanical properties of two single-shade composite resins compared with a conventional multi-shade composite. Omnichroma (OM), Metafil Bulk Fill ONE (BO), and Filtek Z350XT (Z350) were tested. Color adjustment was assessed using A3, B1, and C4 background cavities, and ΔE00 values were calculated. The translucency parameter (TP) was measured, and the flexural strength, flexural modulus, and depth of cure (B/T ratio) were determined. OM and BO showed better color adjustment performance on brighter (B1) backgrounds and decreased matching on darker (C4) ones. OM maintained stable color adjustment across cavity depths, while BO showed improved adjustment in shallower cavities. Both exhibited higher TP values than Z350. The control group (Z350) had the highest flexural strength and modulus, though BO's flexural strength was comparable. OM and BO showed sufficient mechanical strength and a greater depth of cure compared to Z350. Our study indicated that the one-shade composite resins OM and BO exhibited better color adjustment performance compared to conventional composite resins due to the influence of the surrounding shades, with a better adjustment ability on brighter backgrounds. Additionally, OM and BO demonstrated sufficient strength and a higher depth of cure compared to the control group.

In recent years, 3D printing has become a key technology for producing intricate geometries with high precision. Beta titanium alloys (β-Ti), due to their excellent combination of strength, ductility, low elastic modulus, and biocompatibility, are widely used in the aerospace and medical industries. However, the unique microstructure formed during additive manufacturing characterised by porosity, residual stress, and anisotropy can significantly influence the mechanical performance and durability of these materials. This study examines how different printing parameters affect porosity, dimensional stability, and mechanical properties in the β-Ti alloy Ti25Nb4Ta8Sn. The investigation focuses on thin-walled samples and gyroid structures, which represent model geometries for porous biomedical components. These structures, defined by a periodic network of interconnected channels, provide a useful platform for studying the relationship between geometry and mechanical response. In addition, the effects of surface etching on the morphology and compressive behaviour of printed gyroid structures were evaluated. Compression testing was used to determine how etching alters load-bearing performance and to identify correlations between surface modification and mechanical response. The combined analysis enables optimisation of both printing and post-processing parameters for advanced biomedical applications.

Objective: This study aimed to evaluate peri-implant tissue changes during early osseointegration using a combined approach of digital radiographic analysis, RGB pseudocolorization, and histomorphometry in a sheep tibia model.

Materials and methods: Thirty titanium implants were placed in the tibiae of six adult sheep and evaluated at 14 and 28 days post-implantation. Digital periapical radiographs were acquired, grayscale values and RGB channel intensities were measured using Fiji/ImageJ, and compared with histological parameters (bone tissue, collagen, and medullary spaces) quantified from picrosirius-hematoxylin-stained sections. Manual overlay of radiographic and histological images was performed to ensure spatial correspondence of regions of interest. Statistical analyses assessed differences over time and correlations between image data and histological composition.

Results: Radiographic grayscale values and histologically measured bone and collagen increased significantly from 14 to 28 days (p < 0.01), while medullary spaces decreased (p < 0.001), indicating progressive bone formation and matrix maturation. RGB analysis revealed significant increases in green channel intensity and decreases in red channel intensity (p < 0.05), while the blue channel remained stable. At 14 days, strong correlations were observed between blue channel intensity and bone tissue (r = 0.81; p = 0.015), and between green channel intensity and collagen (r = 0.98; p < 0.001). Visual overlays demonstrated alignment between radiographic high-density zones and histologically dense bone regions.

Conclusions: RGB pseudocolorized radiographic analysis, correlated with histological findings, offers a non-invasive and reproducible method for early detection of peri-implant tissue maturation. This feasibility correlation study provides a foundation for future investigations integrating imaging, histology, and biomechanical testing.