Chronic oral and maxillofacial diseases are frequently associated with progressive alveolar bone loss, leading to impaired structural integrity of the jaw and increased risk of implant failure, microbial colonization, and microfracture formation. Ceramic scaffolds such as those made of hydroxyapatite (HA) and β-tricalcium phosphate (β-TCP) have attracted considerable attention because of their controlled resorption properties and the promotion of rapid new vital bone formation. The aim of this research is to enhance the performance of scaffolds composed of HA and β-TCP used for guided bone tissue regeneration in oral surgery. HA/β-TCP scaffolds were loaded with simvastatin (SIMV) and coated with multiple layers of alginate (ALG). The proposed strategy was designed to achieve a local and prolonged drug release while simultaneously improving mechanical properties. The scaffolds were characterized in terms of porosity, water absorption, in vitro degradation, in vitro bioactivity, and SIMV release. In addition, microscale mechanical properties were evaluated using Brillouin microscopy before and after the coating process. Cytocompatibility was further evaluated by using murine macrophages as an in vitro cellular model. The results demonstrated that ALG coatings significantly modulated SIMV release, promoting a delayed drug release. Moreover, ALG deposition improved the micromechanical properties of the scaffolds, conferring a dual structure analogous to those of bone tissue. These findings indicate that ALG-coated SIMV-loaded HA/β-TCP scaffolds represent a promising multifunctional platform for the medical field.
Background/Aim: Restorative materials in pediatric dentistry are frequently exposed to acidic oral liquid medications, which may alter their surface properties and color. This in vitro study compared the surface roughness, three-dimensional topography, and color stability (ΔE00) of a glass hybrid restorative system (GH), a polyacid-modified composite resin (PMC), and a nanohybrid bulk-fill resin composite (NHC) following a standardized repeated-exposure protocol to two pediatric antihistamine syrups: ketotifen (Zaditen®) and cetirizine (Zyrtec®). Materials and Methods: Disc-shaped specimens were randomly allocated to three immersion subgroups per material (Zaditen®, Zyrtec®, distilled water). After baseline measurements (t0), specimens underwent 5000 thermal cycles (t1), then immersion in the assigned solution for 5 min, twice daily, for 6 days (t2). Ra and ΔE00 were evaluated quantitatively; surface degradation was further characterized descriptively using 3D optical profilometry and SEM. Data were analyzed using a three-way mixed-design ANOVA (Time × Material × Solution). Results: Antihistamine syrup exposure was associated with significant changes in surface topography and color stability (p < 0.001), with large-to-moderate effect sizes for time and its interactions. GH showed the highest Ra and largest color change, but much of this occurred after thermocycling, before syrup exposure. NHC and PMC generally showed smaller changes than GH. 3D profilometry and SEM revealed material-specific morphologies, interpreted descriptively rather than as confirmed degradation mechanisms. Conclusion: Standardized repeated exposure to ketotifen and cetirizine syrups was associated with material-dependent changes in surface topography and color stability, with GH showing the greatest change and NHC/PMC comparatively greater stability; clinical extrapolation requires further study.
Objective: This study aimed to evaluate the long-term degradation behavior, biostimulatory effects, and biocompatibility of a novel poly-L-lactic acid-block-polyethylene glycol/hyaluronic acid (PLLA–b–PEG/HA) composite filler for soft tissue augmentation. Methods: PLLA–b–PEG/HA microsphere properties were characterized via scanning electron microscopy (SEM), X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), nuclear magnetic resonance hydrogen spectroscopy (1H NMR), thermogravimetry (TG) and differential scanning calorimetry (DSC). A 104-week in vivo rabbit model was established to systematically observe filler degradation and tissue responses. Ultrasound monitoring, histological staining, ELISA and RT-PCR were performed to assess volumetric changes, inflammatory reactions and collagen synthesis-related signaling. Results: Physicochemical property tests demonstrated that PLLA–b–PEG retains the fundamental physicochemical properties of pristine PLLA while exhibiting enhanced hydrophilicity. B-ultrasound demonstrated a presented uniform in vivo distribution without displacement or diffusion over time, confirming steady and predictable degradation. SEM verified progressive morphological degradation and porous evolution of the microspheres. The filler induced a mild, balanced inflammatory microenvironment with early expression of both pro-inflammatory (IL-12, TNF-α) and anti-inflammatory (IL-4) cytokines, which resolved gradually over time. Sustained TGF-β upregulation persisted throughout the 104-week observation period, driving continuous neocollagenesis and prominent neoelastogenesis, thereby achieving favorable and long-term tissue remodeling with excellent biocompatibility. Conclusions: The PLLA–b–PEG/HA composite filler exhibits controllable degradation properties and homeostatic regulatory effects, along with outstanding long-term biosafety and tissue integration capacity. As an ideal biostimulatory filler for soft tissue augmentation, it can effectively facilitate the regeneration of high-quality functional extracellular matrix rich in collagen fibers and elastic fibers, and holds promising clinical prospects for natural and long-lasting soft tissue filling applications.
Background: Three-dimensional (3D) printing and bioprinting have emerged as transformative technologies in tissue engineering and regenerative medicine. Conventional 3D printing enables the fabrication of complex, customizable scaffolds that mimic the native extracellular matrix (ECM), providing mechanical support essential for cell adhesion, proliferation, and differentiation. In contrast, 3D bioprinting integrates biomaterials, growth factors, and living cells into bioinks, allowing the precise layer-by-layer construction of tissue-like structures. Objective: This review aims to highlight recent advances and applications of both conventional 3D printing and 3D bioprinting in regenerative medicine, with a specific focus on craniofacial tissue regeneration. Particular emphasis is placed on the distinct roles of scaffold-based and cell-laden approaches. Methods: A comprehensive analysis of the current literature was conducted to examine both conventional 3D printing and bioprinting approaches used in craniofacial tissue engineering. Emphasis was placed on printing techniques, bioink composition and selection, scaffold design, and cell sources, as well as their applications across multiple tissue types. Results: Recent developments demonstrate that conventional 3D printing enables the fabrication of customizable scaffolds, whereas 3D bioprinting enables the generation of highly organized, cell-laden constructs that closely resemble native tissue architecture. These technologies have shown promising outcomes in developing patient-specific disease models and regenerative implants for craniofacial tissues, including bone, dental, tracheal, ocular, muscle, and neural tissues. Conclusions: 3D printing and bioprinting offer powerful platforms for craniofacial regenerative medicine. Ongoing advancements in bioink formulation, printing precision, and biological integration are expected to further enhance their translational and clinical potential.
Background and Objectives: Magnesium-based biomaterials are increasingly investigated due to their biodegradability, bone-like elastic modulus, and potential osteogenic properties. However, alloy composition may influence degradation behavior and local tissue response. This study aimed to assess and compare the local biocompatibility, degradation characteristics, and bone regenerative response induced by Mg-Zn-Mn-Ca and Mg-Nd-Y-Zr-Zn magnesium alloy powders. Materials and Methods: Two magnesium alloys were evaluated through physicochemical characterization, in vitro osteoblast cytocompatibility and antimicrobial assays, and in vivo testing in Sprague–Dawley rats. Standardized cylindrical defects were created in the medial femoral condyle and filled with either Mg-Nd-Y-Zr-Zn or Mg-Zn-Mn-Ca alloy powders, while untreated defects served as controls. Bone remodeling and defect healing were assessed by micro-computed tomography, allowing three-dimensional qualitative and quantitative evaluation of newly formed bone. Scanning electron microscopy was used to analyze surface morphology and degradation features, while histopathological examination assessed inflammation, osteogenesis, and tissue integration at the implant site. Results: Both magnesium alloy powders showed antimicrobial potency and elicited no cytotoxic effects in vitro, while animal studies revealed progressive biodegradation over time, associated with new bone formation within and around the defect area. Micro-CT analysis demonstrated active bone remodeling in experimental groups, with differences in bone distribution and defect-filling patterns between Mg-Nd-Y-Zr-Zn and Mg-Zn-Mn-Ca implants. SEM revealed alloy-specific degradation morphologies. Histological evaluation showed a moderate early inflammatory response that decreased at later time points, together with ongoing osteogenesis and favorable tissue integration. No severe local adverse reactions or persistent inflammation were observed. Conclusions: Both Mg-Nd-Y-Zr-Zn and Mg-Zn-Mn-Ca alloy powders were locally biocompatible and supported bone regeneration in a rat femoral condyle defect model. Differences in degradation behavior and tissue response emphasize the relevance of alloy composition in developing magnesium-based biomaterials for bone defect treatment.
Angled abutments and cantilever extensions in bar-supported full-arch implant prostheses may generate bending moments and localized stress concentrations within prosthetic components and peri-implant bone. Implant-supported rehabilitation becomes biomechanically more demanding in completely edentulous patients with posterior bone resorption. Therefore, understanding how connection geometry, cantilever length, and framework material influence prosthetic design is important. In this study, a three-dimensional mandibular model generated from CT data was used to compare conventional and spherical abutment–bar connection designs in All-on-Four prostheses with 30° angled posterior abutments. Cantilever lengths of 8, 10, and 12 mm were evaluated, and Ti6Al4V Grade 5 and PEEK were assigned as alternative bar prosthesis materials. Finite element analyses were performed in ANSYS Workbench, and von Mises stress distributions were evaluated in the bar prosthesis, prosthetic screws, abutments, implants, and surrounding cortical and trabecular bone. The results showed that increasing cantilever length increased stress levels in prosthetic components and bone tissues. The spherical connection design generally reduced stresses in the most critical distal components compared with the conventional design; however, this reduction was not uniform for all components, particularly in the PEEK models. The highest stress value was observed in the posterior angled abutment of the PC-12 model with a PEEK bar prosthesis (1592.2 MPa). Among the implant components, the lowest stress was observed in the anterior implant of the TS-8 model (27.99 MPa). In contrast, the lowest bone stress was recorded in the anterior trabecular bone capsule of the PC-8 model. These findings indicate that cantilever length and connection geometry are critical parameters in designing full-arch implant prostheses. At the same time, the use of PEEK as a bar material should be interpreted with caution under extended-cantilever conditions.
Background: Injectable bone graft substitutes offer a practical alternative to preformed ceramic scaffolds by adapting to irregular bone defects while preserving osteoconductive properties. This study investigated the in vivo performance of hydroxyapatite/tetracalcium phosphate (HA/TTCP) granules, uncoated or alginate-coated, with or without autologous ovine bone marrow concentrate (oBMC), in a standardized sheep bone defect model. Methods: oBMC was characterized for cellular composition, viability, and recovery. Implanted HA/TTCP formulations were evaluated after 6 and 12 weeks by micro-computed tomography and histomorphometry. Results: Uncoated HA/TTCP granules promoted bone formation, integrating with host bone. Alginate coating improved injectability and handling but influenced granule organization and degradation. Uncoated HA/TTCP + oBMC showed a more favorable response than the coated formulation, with higher bone-to-implant contact (p = 0.004) and bone volume (p = 0.031) at 12 weeks. A modest increase in peri-implant bone volume was observed from 6 to 12 weeks in the HA/TTCP + oBMC group, though this did not retain statistical significance once clustering was accounted for. No significant direct effect of oBMC was observed compared with the cell-free formulation. Conclusions: Injectable HA/TTCP granules + oBMC represent a promising single-step strategy for irregular bone defects, although further coating optimization is needed to preserve biological performance while maximizing handling advantages.
(1) Background: Hybrid injectable biomaterials incorporating poly-D,L-lactic acid (PDLLA) and hyaluronic acid (HA) have emerged as an important class of biostimulators in aesthetic medicine, combining immediate soft-tissue augmentation with sustained collagen biostimulation. Although inadvertent intravascular injection is uncommon, it may lead to severe vascular complications. However, experimental data on the intravascular behaviour of PDLLA-HA hybrid biostimulators remain limited. This study evaluated vascular flow changes, countercurrent flow, and tissue response following intra-arterial injection of Juvelook® and Juvelook Volume® (VAIM Co., Ltd., Seoul, Republic of Korea) in a rabbit ear model. (2) Methods: A total of 112 rabbits (56 animals per product) were studied using an identical protocol. Each rabbit received bilateral intra-arterial injections of either 0.1 or 0.2 mL of PDLLA-HA hybrid biostimulator prepared at the manufacturer’s recommended 6 mL reconstitution or at serial dilutions ranging from 12 to 42 mL. Immediate vascular flow, countercurrent flow, macroscopic skin changes, and histopathological findings were evaluated over a 7-day observation period. (3) Results: At an injection volume of 0.1 mL, both products dispersed throughout the arterial system without persistent vascular occlusion or tissue necrosis. At 0.2 mL, transient vascular occlusion occurred in the standard (6 mL) and 12 mL dilution groups, with spontaneous restoration of blood flow within 5 min. Countercurrent flow was observed only in the Juvelook Volume® (VAIM Co., Ltd.) cohort under these conditions. No skin necrosis, intravascular thrombosis, or embolisation was observed. Histopathological examination demonstrated preserved vascular integrity, with only focal perivascular foreign-body reactions consistent with injectable biomaterials. (4) Conclusions: Neither biostimulator caused persistent vascular occlusion or clinically significant tissue injury under the experimental conditions investigated. Injection volume and dilution influenced transient vascular flow disturbance and countercurrent behaviour. These findings provide experimental evidence that improves current understanding of the short-term intravascular behaviour of PDLLA-HA hybrid biostimulators and may contribute to future assessments of vascular safety.
Objectives: Clinical outcomes of peri-implant soft tissue augmentation remain variable, and baseline-associated factors of treatment response are poorly understood. This exploratory study aimed to evaluate baseline-associated patterns of peri-implant soft tissue gain following augmentation with connective tissue grafts (CTG) and volume-stable collagen matrices (VCMX). Materials and Methods: This study represents a secondary analysis of a randomized clinical trial including 32 implant sites (CTG, n = 16; VCMX, n = 16). Peri-implant soft tissue thickness (STT) was measured using high-frequency ultrasonography at baseline (T0), 3 months (T1), and 12 months (T2). Absolute and relative STT gains were analyzed, and their relationship with baseline thickness was assessed. Results: Both augmentation approaches resulted in significant increases in soft tissue thickness, with most of the gain occurring during the early healing phase. At 12 months, CTG demonstrated greater absolute tissue gain than VCMX. At the mid-buccal measurement site, mean relative gain was approximately 225% with CTG and 147% with VCMX. The strongest inverse correlation between baseline STT and relative gain was also observed at this site in the CTG group (r = −0.815, p < 0.001). Sites with thinner tissues showed greater proportional increases, whereas thicker tissues demonstrated a reduced relative response. Conclusions: Relative soft tissue gain was inversely associated with baseline soft tissue thickness. Thinner tissues exhibit greater proportional increases, whereas thicker tissues demonstrate a lower relative gain. These findings support a phenotype-informed and individualized approach to peri-implant soft tissue management.
Hydrogels are hydrated three-dimensional polymeric networks with biomedical potential because they can encapsulate therapeutic agents and provide localised, sustained, or stimulus-responsive drug delivery. Their performance is determined by interacting variables, including polymer composition, synthesis route, crosslinking chemistry, drug loading, swelling, degradation, and the biological microenvironment. This multidimensional design space often makes hydrogel development slow and dependent on trial-and-error experimentation. This review examines the data-driven development of biomedical hydrogels for controlled drug delivery, focusing on clinical applications and emerging machine-learning approaches that support material selection, formulation design, synthesis optimisation, and release prediction. The review first discusses natural and synthetic hydrogels, including alginate, chitosan, gelatin-based systems, hyaluronic acid, and polyethylene glycol, with emphasis on how their physicochemical properties influence biocompatibility, synthesis flexibility, and drug-release behaviour. Key applications are then considered, including wound healing, cancer therapy, glucose-responsive insulin delivery, and inflammatory disease management. Particular attention is given to injectable and stimuli-responsive hydrogels, where formulation conditions and synthesis parameters can be tuned to improve localisation, therapeutic exposure, and release control. The review evaluates machine-learning methods, including random forest, gradient boosting, artificial neural networks, Gaussian process regression, and active learning, for predicting hydrogel properties, modelling release profiles, optimizing synthesis and formulation variables, and prioritizing experimental candidates. Finally, translational challenges are addressed, including small non-standardised datasets, limited external validation, weak in vitro-clinical correlations, material safety, explainability, reproducibility, scalability, and regulatory requirements. By integrating clinical, materials, synthesis, and machine-learning perspectives, this review highlights opportunities for developing safer and clinically relevant hydrogel-based drug-delivery systems.
Complex patient-specific bone defects remain difficult to reconstruct because the regenerative capacity of bone is limited and prefabricated implants cannot readily match defect geometry. In this work, methylcellulose-gelatin-hydroxyapatite (MC/GEL/HA) inks were formulated with varying methylcellulose content and hydroxyapatite incorporation, crosslinked with EDC/NHS, and 3D-printed into porous scaffolds with defined square-pore architectures. Inks were evaluated by oscillatory and steady-shear rheology, and printed scaffolds were characterized for morphology, chemical composition, mechanical performance, physicochemical stability, wettability, apatite-forming bioactivity, and osteogenic responses of human bone marrow mesenchymal stem cells. Methylcellulose content primarily governed ink rheology and printability, and increased compressive strength (up to ~0.38 MPa for 15MC/10GEL/30HA), whereas hydroxyapatite enhanced surface hydrophilicity, promoted apatite nucleation within 7 days in simulated body fluid, and markedly increased alkaline phosphatase activity (>10-fold over HA-free scaffolds), mineralization (~2-fold by Alizarin Red), and the highest osteocalcin expression among the HA-containing formulations (~2.45-fold at day 14). The 15MC/10GEL/30HA formulation showed the most favorable balance of printability, mechanical performance, and osteogenic performance. These complementary functions reconciled structural stability with osteogenic performance, supporting the MC/GEL/HA system as a tunable bioink platform for non-weight-bearing bone regeneration, while warranting further in vivo validation.
The host immune response plays a central role in determining biomaterial performance, particularly through early macrophage activation dynamics at the tissue–biomaterial interface. This study evaluated the response of THP-1-derived human macrophages cultured on a fibrous extracellular matrix-like polydioxanone (PDO) mesh under basal (M0), M1-induced, and M2-induced in vitro conditions. Macrophage responses were assessed by gene expression analysis, immunofluorescence staining of macrophage- and polarization-associated markers, scanning electron microscopy (SEM), and metabolic and viability assays. Distinct stimulus- and time-dependent responses were observed across transcriptional, marker distribution, morphological, and metabolic readouts. Pro-inflammatory gene expression increased under M1-polarizing conditions at 72 h and declined at 96 h, whereas anti-inflammatory and M2-associated markers progressively increased under M2 stimulation, reaching higher levels at 96 h. Immunofluorescence confirmed macrophage differentiation under basal conditions and showed condition-dependent distributions of CD86- and CD206-associated signals, consistent with the transcriptional profiles. SEM revealed stable cell–material interactions and polarization-associated morphological heterogeneity. Metabolic and viability assays confirmed viable cells under all conditions, with activity patterns consistent with induced activation states. Under basal (M0) conditions, macrophages cultured on the PDO mesh maintained a basal phenotype without evidence of marked pro-inflammatory activation. Overall, these findings indicate that fibrous PDO meshes support macrophage viability, differentiation, and stimulus-responsive activation, highlighting their potential as immunologically compatible polymeric platforms for regenerative biomaterial applications.
Demineralized bone matrix (DBM)-derived allografts retain extracellular matrix (ECM)-associated factors involved in bone repair, but biochemical protein recovery alone may not predict functional pathway activation. We evaluated the HEK-Blue™ TGF-β Reporter Assay as a targeted method for assessing Smad-dependent reporter activity in DBM-derived materials. ECM proteins were extracted from cortical demineralized bone granules (DBG) using guanidine hydrochloride (GuHCl) or urea and quantified after extraction, dialysis, and sterile filtration. Reporter cells were stimulated with extracted ECM proteins or directly with processed cortical and cancellous products, including DBG, wet heat-treated DBG formulated as Putty (PHT), and gamma-irradiated PHT (PGI). Non-pooled DBM sponge samples were also tested. Secreted embryonic alkaline phosphatase (SEAP) activity served as the functional reporter readout. Material-only no-cell controls assessed material-derived background. PrestoBlue™ readouts served as exploratory quality controls. The urea-derived extract yielded a higher apparent BCA-detectable protein concentration than the GuHCl-derived extract. Only the GuHCl-derived extract induced increasing SEAP activity at matched protein input. Direct stimulation showed reporter activation above the TNF-α pathway-negative cytokine control for cortical DBG, PHT, PGI, and cancellous DBG. DBM sponges also induced detectable SEAP activity. These findings support targeted functional screening of Smad-dependent TGF-β reporter activation in DBM-derived materials, but not total osteoinductivity assessment.
Bone loss represents a significant clinical burden that has driven the development of improved orthopedic graft substitutes. Although current grafting options, including autografts, allografts, and xenografts, have demonstrated considerable therapeutic potential, their widespread application is constrained by limitations such as donor scarcity, limited availability, and associated clinical risks. Consequently, biologically derived materials, including avian eggshells and marine bivalve shells, have emerged as promising alternative sources to produce bone precursor materials and next-generation bone graft substitutes. This review summarizes recent advances in avian eggshell- and marine shell-derived calcium carbonate (CaCO3) materials for bone regeneration and examines their preclinical evaluation in diverse animal models, including critical-size defects in calvarial, femoral, radial and mandibular bone. Relevant studies published over the past ten years were systematically analyzed, focusing on natural calcium carbonate systems derived from avian eggshell and marine shells, including oyster, mussel, clam, scallop, cockle, and sea urchins. A structured literature search was conducted using PubMed, Scopus, and Google Scholar to identify studies published between 2015 and 2025 investigating eggshell- and aquatic-derived biomaterials for bone repair and regeneration. Eligible studies were screened, and data were comparatively analyzed with respect to biomaterial source, scaffold fabrication, physicochemical characteristics, mechanical performance, biocompatibility, osteogenic potential, and the use of preclinical animal studies. Eggshell-derived biomaterials currently show the strongest translational evidence, while aquatic shell-derived biomaterials remain promising but underexplored for bone regeneration. Furthermore, this review critically examines the scientific, manufacturing, and regulatory challenges that must be addressed before clinical implementation.
The aim of this study was to evaluate the influence of n-butyl cyanoacrylate (NBCA) coating of freshly mixed mineral trioxide aggregate (MTA) on its microhardness after setting under conditions of moisture and human blood exposure. MicroMega MM-MTA samples were prepared using Teflon molds (6 mm × 4 mm). Four experimental groups (n = 4) were established: control (MTA + phosphate-buffered saline (PBS)), MTA coated with NBCA (PeriAcryl) + PBS, MTA + blood + PBS, and MTA coated with NBCA + blood + PBS. Samples assigned to the blood-exposure groups were exposed to human blood for 15 min, rinsed, and subsequently stored in PBS. Prior to microhardness testing, all samples were incubated in PBS for seven days. Microhardness was measured using a Vickers microhardness tester, with five indentations performed on each specimen (20 measurements per group). Data were analyzed using the Shapiro–Wilk test for normality, Levene’s test, and two-way ANOVA, followed by Tukey’s post hoc test. The analysis revealed significant differences among the experimental groups (p < 0.001). Post hoc analysis demonstrated statistically significant differences between tissue glue-coated and uncoated samples (p < 0.05). Within the limitations of this in vitro study, coating MTA with NBCA tissue glue during the setting period significantly increased its microhardness following exposure to human blood and PBS.
Confined catalysis enhances enzyme activity, stability, and selectivity by encapsulating enzymes in well-defined micro- or nanoscale environments. Unlike conventional immobilization strategies, which primarily stabilize enzymes, this approach actively regulates enzyme behavior, substrate transport, and product removal, addressing challenges in real-world biosensing. In this work, we connect confined catalysis principles with biosensor design requirements, emphasizing tailored microenvironments, hierarchical pore architectures, and cascade reaction optimization to improve sensitivity, selectivity, and operational stability. The review also highlights advanced strategies such as molecular imprinting, aptamer recognition, and DNA scaffold-guided co-localization, which enable precise substrate discrimination and efficient signal amplification. By integrating these confinement strategies with emerging materials, including biological macromolecular materials, amorphous porous materials, and crystalline framework materials, this work outlines pathways to next-generation biosensors with enhanced performance and practical applicability, addressing limitations overlooked in previous studies.
Background: This in vitro study compared the effectiveness of polytetrafluoroethylene (PTFE) tape and a conventional cotton retraction cord for gingival displacement and evaluated the mechanical and microstructural characteristics of PTFE tape. Methods: Eight standardized prepared teeth with artificial gingiva were evaluated under three conditions: control, cotton retraction cord, and PTFE tape. After each condition, impressions were digitized using a CAD/CAM system. Sulcular width was measured at four predefined locations and averaged for statistical analysis. PTFE tape was also evaluated by tensile testing before and after sterilization and by scanning electron microscopy (SEM). Results: Mean sulcular widths were 0.716 ± 0.118 mm (control), 0.851 ± 0.140 mm (cotton cord), and 0.907 ± 0.099 mm (PTFE). Repeated-measures ANOVA showed a significant effect of the displacement method (p < 0.001), with PTFE producing significantly greater sulcular enlargement than cotton cord. Qualitative SEM analysis revealed a more homogeneous impression surface morphology following PTFE removal. Sterilization did not significantly affect the tensile properties or microstructural integrity of PTFE tape. Conclusions: Under standardized in vitro conditions, PTFE tape produced the highest gingival sulcular enlargement and maintained favorable mechanical and microstructural properties, supporting its potential as an alternative gingival displacement material. Further clinical studies are required to confirm these findings.
Chitosan and calcium phosphate (CaP) are attractive bioactive coating materials for titanium (Ti) orthopedic implants, but coating approaches must provide uniform deposition, adequate adhesion, and cytocompatibility. This proof-of-concept study evaluated whether CaP microshells could be incorporated into electrosprayed chitosan coatings bonded to silanized Ti substrates without compromising coating properties. CaP microshells were synthesized using carbon microsphere templates and added to chitosan electrospray solutions at 0.25, 0.5, and 1.0 wt% relative to chitosan. Electrospray parameters were adjusted, and coatings were characterized by scanning electron microscopy, energy dispersive X-ray spectroscopy, Fourier transform infrared spectroscopy, tensile adhesion testing, water contact angle measurements, and W-20-17 bone marrow stromal cell culture. Increasing capillary diameter and reducing pressure enabled stable deposition of uniform composite coatings containing up to 1.0 wt% CaP. CaP microshells were distributed across the coating surfaces and throughout the coating thickness. Silanization significantly increased coating adhesion compared with non-silanized Ti, while CaP incorporation up to 1.0 wt% did not significantly reduce bond strength. All coatings were hydrophilic and supported viable cell attachment and growth over five days. These findings support the feasibility of electrosprayed chitosan–CaP microshell coatings as adhesive, cytocompatible bioactive coating platforms for Ti implant materials.
(1) Background: Orthodontic tooth movement (OTM) during sliding mechanics is influenced by a multitude of interactions. Studies suggest that vibration induced by mastication or usage of electric tooth brushes might impact resistance to sliding (RS) in conventional brackets. In superelastic brackets, archwire sliding might also be altered due to deformation of the bracket wings during mastication. Therefore, the aim of this study was to investigate how the superelastic properties of Nickel–Titanium (NiTi) brackets affect archwire sliding during mastication. (2) Methods: Orthodontic superelastic NiTi archwires with diameters of 0.014” and 0.016” were ligated into four superelastic NiTi brackets. One bracket was positioned with a vertical offset of 1 mm to simulate clinical vertical leveling. A weight force was applied to axially preload the archwire. The occlusal and axial forces affecting the movement of the archwires through the bracket were measured. (3) Results: Low chewing forces caused a measurable axial movement of the 0.014” wire. Increased chewing forces resulted in higher axial movements. The archwire diameter had an impact: 0.014” NiTi required lower masticatory forces to initiate wire motion as compared to the 0.016” NiTi. (4) Conclusions: The superelastic NiTi brackets examined showed that under simulated continuous dynamic masticatory loading, obstacles such as friction or binding could be overcome.
Cranial bone defects remain a significant clinical challenge due to their limited intrinsic regenerative capacity and the complexity of coordinating osteogenesis, angiogenesis, and immune responses within a confined and poorly vascularised environment. Conventional approaches, including autologous grafts and synthetic implants, provide structural support but fail to actively modulate the biological processes required for effective bone regeneration. In this context, hydrogel-based systems have emerged as versatile platforms for localized and controlled drug delivery in cranial bone tissue engineering (BTE). This review provides a comprehensive overview of hydrogel-based delivery strategies designed to regulate the spatiotemporal presentation of bioactive agents within cranial defects. The main classes of hydrogels, natural, synthetic, semi-synthetic, and hybrid systems, are discussed in relation to their physicochemical properties and suitability for drug delivery applications. Current delivery approaches are analysed, including cell-free systems (growth factors, peptides, bioactive ions, nucleic acids, and small molecules drugs), cell-based platforms, and multifunctional systems integrating secondary carriers such as nanoparticles (NPs), microparticles (MPs), and extracellular vesicles (EVs). Particular emphasis is placed on how hydrogel design parameters, including crosslinking density, degradation kinetics, and responsiveness to microenvironmental cues, govern therapeutic release and influence regenerative outcomes. Emerging strategies and key translational challenges are also highlighted.
