Journal of Functional Biomaterials最新文献

Synthetic biomaterials used as bone graft extenders (BGE) in spinal fusion surgery can supplement but do not replace autologous bone. This pilot study evaluated a calcium sulfate/hydroxyapatite (CaS/HA) material as an antibiotic-eluting BGE and a carrier for bone morphogenetic protein-2 (BMP-2) in a rabbit posterolateral lumbar (L4-L5) spinal fusion model (PLF). Pre-set CaS/HA beads were loaded with tobramycin (TOB) and tested for in vitro antibiotic release and antibacterial activity against Staphylococcus aureus. For the in vivo PLF study, CaS/HA beads were used in two treatment strategies: (1) CaS/HA + TOB + autograft (left side) and (2) CaS/HA + BMP-2 (right side). Serum levels of TOB were quantified and spinal fusion was evaluated after 12 weeks. TOB exhibited a rapid initial release, followed by a decline below detectable levels after 6 h in vitro and 48 h in vivo. TOB-loaded CaS/HA beads demonstrated in vitro antibacterial activity for 19 days. In the PLF study, 5/6 and 6/6 specimens were fused radiologically in the TOB and BMP groups, respectively, and 100% using mechanical testing. Micro-CT analysis showed no significant difference in bone volume between the TOB and BMP-2 groups (364 ± 84 vs. 479 ± 95 mm³). Histology verified continuous bone bridging in both groups. Our in vitro findings indicate that locally added TOB could protect the CaS/HA material from bacterial colonization and did not adversely impact the CaS/HA material negatively to act as BGE. The addition of low-dose BMP-2 to the CaS/HA material proved effective in building bone without the need to harvest autologous bone. In summary, this pilot PLF study demonstrates that the tested CaS/HA material combined with BMP-2 could replace autologous bone harvesting in spinal fusion surgery. Addition of TOB could potentially protect the material from bacterial colonization during the early post-operative period but further studies in infection models are warranted.

Background: Intermaxillary elastics are widely used in orthodontics to deliver controlled forces for malocclusion correction, aiding in the correction of anteroposterior, vertical, or transverse problems. Despite their clinical relevance, comprehensive mechanical characterization remains limited. Objective: This study aimed to evaluate the mechanical properties of nine types of intermaxillary elastics available on the market to guide evidence-based clinical selection. Methods: Elastics were tested under uniaxial tensile loading following ISO 37:2011 and ISO 21606:2007, with six replicates per type. Load-displacement and stress-strain responses were analyzed, measuring peak force, elongation at rupture, work-to-rupture, and specific rupture work. Non-linear behavior was modeled using cubic polynomial regression, and normalized stress-strain curves enabled intrinsic material comparisons. One-way ANOVA with post-hoc tests assessed differences among elastics. Results: All elastics displayed characteristic non-linear elastomeric responses. Functional grouping distinguished short-displacement/high-stiffness, intermediate-displacement/moderate-stiffness, and long-displacement/high-capacity bands. Work-to-rupture, specific rupture work, and normalized stress-strain metrics varied significantly, reflecting differences in energy absorption and force delivery (p < 0.05). Conclusions: Mechanical characterization, including energy-based descriptors and normalized stress-strain analysis, supports informed elastic selection, enhancing orthodontic treatment predictability and patient safety.

Type II collagen (CII), the major structural protein in the cartilage extracellular matrix, is a promising biomaterial for scaffold design in cartilage tissue engineering. In this study, high-purity CII was successfully extracted from bovine cartilage, an abundant by-product of cattle slaughter, and its amino acid composition, triple-helical conformation, and thermal stability were verified. CII was subsequently combined with silk fibroin (SF) and chitosan (CS) to fabricate three-dimensional (3D) porous scaffolds via freeze-drying. The pore structure, porosity, swelling behavior, mechanical properties and in vitro degradation characteristics were systematically evaluated. Scaffolds with favorable structural integrity, mechanical performance, and degradation rates were further evaluated biologically using human primary chondrocytes. All CII-based composite scaffolds supported chondrocyte growth and promoted early extracellular matrix deposition. Notably, the scaffold with a CII:SF:CS ratio of 7:3:1 showed the highest GAG/DNA content, accompanied by upregulated gene expression related to the cartilage phenotype (COL2A1, ACAN, and SOX9) and reduced expression of the dedifferentiation marker COL1A1, indicating improved phenotype maintenance. Overall, within the tested range, CII70 (CII:SF:CS = 7:3:1) represents a practical compromise between scaffold stability and in vitro chondrocyte-related outcomes, providing a basis for selecting CII/SF/CS formulations for cartilage tissue engineering.

Rapid vascularization is essential for bone regeneration in oral and maxillofacial surgery. This systematic review synthesised in vivo evidence on 3D-printed composite scaffolds in rodent critical-size calvarial defects quantified by Microfil perfusion and micro-CT. "Composite" was defined as an organic-inorganic construct within the printed scaffold (not a single-phase scaffold with a surface coating). PubMed, MEDLINE, and Web of Science Core Collection were searched for studies published from January 2014 to December 2025. Eligible studies compared composite scaffolds with non-composite (single-phase) scaffolds and/or empty controls and reported vascular outcomes (vessel number, vascularized area) together with bone outcomes (new bone area, bone volume fraction [BV/TV], and bone mineral density). Ten studies met the inclusion criteria. In outcome-specific exploratory analyses, composite scaffolds were associated with higher new bone area than comparators (p = 0.031). Functional modifications were associated with higher vascularized area (p = 0.025) and higher new bone area (p = 0.038), while dual-factor modifications showed the largest gain in new bone area (p = 0.002). Pore sizes ≥ 400 μm were associated with higher BV/TV (p = 0.029). Heterogeneity in designs, follow-up, and reporting, together with small sample sizes, precluded meta-analysis. Composite scaffolds appear promising, but standardised methodologies and improved reporting are needed to define optimal design features and support translation.

Background/objectives: This study evaluated the influence of key biomechanical parameters-orthodontic force magnitude, loading direction, and insertion depth-on stress and strain distribution in orthodontic mini-implants using three-dimensional finite element analysis (FEM).

Methods: A three-dimensional model of a titanium orthodontic mini-implant inserted into a mandibular bone segment was developed and analyzed under varying force magnitudes (1-10 N), loading directions (30°, 45°, and 60°), and insertion depths (2-4 mm). Cortical and cancellous bone components were included, and static loading conditions were applied using simplified, linear elastic material assumptions.

Results: Stress and strain levels increased with higher force magnitudes, with implant stresses approaching critical values at loads above 9 N. Cortical bone stresses remained within physiological limits, whereas cancellous bone exceeded the microdamage strain threshold at forces greater than 3 N. A 60° loading direction reduced implant bending and strain, while deeper insertion significantly decreased strain and displacement, indicating improved primary stability.

Conclusions: Within the limits of this computational model, optimal mechanical behavior was observed under 1-3 N forces, a 60° loading direction, and a 2-4 mm insertion depth. Loads above 9 N approached fatigue and interfacial risk. These findings provide computational insight into the biomechanical behavior of orthodontic mini-implants under the modeled conditions.

Low-intensity pulsed ultrasound (LIPUS) has emerged as a versatile, non-invasive physical modality with growing potential in regenerative medicine and neural repair. Advances in ultrasound physics and biomedical engineering have enabled precise spatiotemporal control of acoustic stimulation, positioning therapeutic ultrasound as an alternative to conventional pharmacological and surgical interventions that often suffer from limited targeting and substantial side effects. Unlike high-intensity focused ultrasound, which relies primarily on thermal ablation, LIPUS operates within a low-energy, non-thermal regime and modulates cellular behavior through mechanical cues, mechano-transduction, and downstream biological responses. Accumulating evidence demonstrates that LIPUS regulates calcium dynamics, cytoskeletal remodeling, neurotrophic factor expression, inflammation, myelination, and local vascular remodeling, thereby promoting functional recovery in both peripheral and central nerve injury models. Moreover, the integration of LIPUS with biomaterials, including piezoelectric scaffolds and acoustically responsive drug delivery systems, has expanded its functionality from direct stimulation to on-demand electrical signaling and controlled therapeutic release. Despite these advances, challenges remain regarding parameter standardization, mechanistic consistency, and clinical translation. In this review, we summarize the systems, parameters, and biological mechanisms underlying LIPUS, discuss its applications in peripheral and central nerve injury repair, and highlight emerging strategies and translational barriers toward intelligent, multimodal, and personalized ultrasound-based therapies.

This study compared the mechanical and thermal properties of new and retrieved multizone rhodium-coated superelastic nickel-titanium (NiTi) archwires across anterior and posterior segments. Using three-point bending tests, Scanning Electron Microscopy with Energy-Dispersive Spectroscopy analysis, and multiple linear regression, it was found that the posterior segments of new wires generated forces 0.50-0.80 N higher than those of anterior or retrieved specimens. While anterior segments exhibited higher austenite start and finish temperatures (by 6.15 °C and 5.21 °C, respectively) compared to posterior segments, these temperatures remained below average intraoral levels, and clinical retrieval did not significantly alter transformation temperatures. However, retrieved wires produced lower overall forces, likely due to surface cracking identified through microscopy. Ultimately, while posterior segments consistently generate higher forces than anterior segments, the observed reduction in force over time and the risk of surface degradation led to the conclusion that these archwires are not recommended for tooth movements exceeding 2 mm.

The success of titanium dental implants rely on osseointegration, influenced by surface properties and early immune responses. While sandblasted and acid-etched (SLA) titanium surfaces have shown clinical success, macrophage-mediated immune responses at these interfaces remain poorly understood. Anatase nanostructures have been shown to influence macrophage polarization on smooth titanium, but their effects on micro-rough SLA surfaces are not fully explored. This study investigates the immunomodulatory effects of micro-nanostructured anatase coatings on SLA titanium using human monocyte-derived macrophages (MDMs). M0-MDMs, were cultured and polarized to M1 and M2- macrophages on Ti-machined, Ti-SLA, Ti-SLA-anatase, and coverslip control surfaces for 48 h. Macrophage behavior was assessed using CCK-8 assay, confocal microscopy, SEM, ELISA, and qRT-PCR. All surfaces demonstrated excellent cytocompatibility, with similar macrophage viability across all investigated groups. M1 macrophages showed upregulation of CCR7 and TNF-α, while M2 macrophages expressed CD209 and CCL13 across all surfaces. Importantly, Ti-SLA-anatase did not significantly alter M1 or M2 markers, cytokine secretion, or gene expression, and did not exacerbate inflammatory responses. Micro-nanostructured anatase coatings on SLA titanium are immunologically well-tolerated and do not increase inflammation. These findings, combined with previously reported enhanced osteogenic properties, suggest the clinical potential of anatase-coated SLA surfaces.

Additive manufacturing is now an integral part of digital prosthodontic workflows, and although stereolithography (SLA) is widely used for denture base fabrication, the dimensional accuracy of printed dentures remains highly dependent on manufacturing parameters, particularly build orientation. This study evaluated the influence of build orientation on the trueness and precision of SLA-printed maxillary and mandibular denture bases. Thirty complete denture bases were fabricated using SLA and divided into three groups according to build orientation: 0°, 45°, and 90° (n = 10). The intaglio surfaces of the printed dentures were scanned and compared with their corresponding digital reference models using three-dimensional inspection software. Trueness was quantified using root mean square error (RMSE) and directional deviations, while precision was assessed based on the variability of RMSE values within each group. Statistical analysis was performed using one-way ANOVA and Tukey's post hoc test (p ≤ 0.05). Build orientation significantly affected the trueness of maxillary denture bases, with dentures printed at 90° demonstrating the lowest RMSE values. No statistically significant differences in trueness were observed among build orientations for mandibular denture bases. Precision was not influenced by build orientation for maxillary dentures, whereas mandibular dentures printed at 90° exhibited significantly greater variability compared with 0° and 45°. Build orientation is a critical factor influencing the dimensional accuracy of SLA-printed denture bases in an arch-dependent manner. Optimizing build orientation may enhance both accuracy and reproducibility, thereby improving the predictability and clinical reliability of additively manufactured denture bases.

The success of orthodontic therapy depends on the effective, continuous application of forces to teeth. Therefore, an essential element of the treatment is the adhesion between the bracket and enamel. The purpose of this study was to evaluate the influence of bracket base design and bonding system on shear bond strength. The study was conducted on eighty extracted premolars which were randomly divided into four groups of twenty teeth each, using two types of metal brackets (80-gauge mesh and anchor pylons base design) and two types of bonding systems (conventional and self-etching). The combination of bracket and bonding system resulted in four distinct configurations of bracket bonding, with each configuration tested on twenty teeth. Shear bond strength testing was performed using a Laryee Universal Testing Machine. The obtained values were statistically analyzed. Slightly higher shear bond strength values were recorded for brackets with anchor pylons bonded using the conventional bonding system (13.32 ± 4.20 N/mm²), whereas the lowest values were recorded for the same bracket base design bonded with the self-etching system (11.10 ± 4.50 N/mm²). Nevertheless, ANOVA test did not reveal statistically significant differences between the two bracket types or between the two bonding techniques in terms of shear bond strength and force values and no significant interaction effects were observed. Considering the obtained results, several additional factors must be taken into account when evaluating the shear bond strength of orthodontic brackets.