Journal of Functional Biomaterials最新文献

Titanium dioxide nanotubes (TNTs) have favorable biocompatibility and nanoscale morphologies, and they have been extensively explored for titanium implant surface modifications. However, they are limited by their mechanical strength and weak interfacial adhesion between the nanotube layer and the titanium substrate. This restricts their clinical applications. In this study, a two-step electrochemical anodization method is developed to achieve in situ tantalum (Ta) doping into TNT arrays to enhance their mechanical performance without altering their nanotubular structure. The surface morphology, element and crystal phase composition, surface roughness, wettability, and mechanical properties of the Ta-doped TNTs were then thoroughly characterized. Scanning electron microscopy revealed that the Ta doping did not change the nanotube architecture. In addition, X-ray diffraction confirmed anatase TiO₂ formation in all the samples. X-ray photoelectron spectroscopy demonstrated that Ta⁵⁺ doping significantly reduced oxygen vacancies, and this was a concentration-dependent effect. Nanoindentation and scratch tests showed that the hardness, the Young's modulus of the nanotube layer, and the adhesion strength between the nanotubes and the titanium substrate were markedly improved compared to those of the undoped TNTs. These mechanical enhancements may be attributed to lattice densification due to Ta doping. In vitro cell assays further demonstrated that the Ta-TNTs promoted rat bone marrow mesenchymal stem cell adhesion, proliferation, and osteogenic differentiation. This was evidenced by increased alkaline phosphatase activity, enhanced mineralization, and upregulated gene expression levels. The results suggest that the Ta-doped TNTs offer a pathway for the development of mechanically robust and bioactive implant surfaces for dental and orthopedic applications.

Context: The increasing incidence of secondary caries and the failure of restorations have intensified research into dental restorative materials capable of actively interacting with the oral environment. In this context, antibacterial and bioregenerative nanomaterials have attracted growing scientific interest due to their potential to inhibit biofilm formation while simultaneously supporting mineral repair processes.

Objective: This narrative review analyzes recent developments in nanostructured materials for restorative dentistry and oral health applications, with particular emphasis on antibacterial agents, bioactive systems, and emerging dual-function approaches that integrate multiple biological functions into restorative materials.

Scope of the review: The analyzed literature indicates that metallic nanoparticles, cationic monomers, and natural nanopolymers can reduce bacterial adhesion and metabolic activity under experimental conditions. In parallel, bioactive nanomaterials such as nanohydroxyapatite, bioactive glass, and calcium phosphate-based systems have demonstrated the ability to release remineralizing ions and to promote mineral deposition at the tooth-material interface. Dual-function hybrid materials aim to combine these antibacterial and bioregenerative effects within a single restorative system. Interpretative Perspective: Despite these advances, most available evidence derives from in vitro and preclinical studies, with significant heterogeneity across experimental models, evaluation methods, and outcome variables. This variability limits direct comparisons between studies and necessitates a cautious interpretation of claims regarding long-term antibacterial efficacy, functional tissue regeneration, and routine clinical applicability.

Conclusions: Antibacterial and bioregenerative nanomaterials represent a relevant and continuously evolving research direction in restorative dentistry. Their successful clinical translation will depend on establishing standardized testing protocols, conducting comprehensive safety assessments, and generating clinically relevant evidence supporting long-term efficacy and biological compatibility. Their successful clinical translation will depend on establishing standardized testing protocols, conducting comprehensive safety assessments, and generating clinically relevant evidence supporting long-term efficacy and biological compatibility.

Introduction: The fracturing of abutment screws is a recurrent technical complication in implant-supported prostheses that may compromise prosthetic maintenance. Although multiple retrieval approaches have been described, comparative data under controlled experimental conditions remain limited. Materials and Methods: This in vitro pilot study evaluated the retrievability of fractured abutment screws when using three commonly applied instruments: an ultrasonic scaler, a fissure bur, and a screw removal kit. Eighteen implants from a single implant system were embedded in epoxy resin, and abutment screws were fractured under clockwise monotonic torque either with (w/A) or without (w/oA) abutments (n= 3 per retrieval method). Retrieval success and procedure time were recorded. Scanning electron microscopy (SEM) was performed to qualitatively assess deformation of the implant internal hex and screw thread morphology. Results: Fracture torque values were higher in specimens fractured with abutments compared with those without abutments. Fractures induced without abutments appeared to extend deeper within the screw channel, engaging a greater number of internal threads. In this pilot study, a shorter retrieval time was observed with the screw removal kit and fissure bur compared with the ultrasonic scaler, although retrieval outcomes varied between specimens. SEM observations suggested differing patterns of internal hex deformation between the retrieval techniques. Conclusions: Within the limitations of this in vitro pilot study, different retrieval approaches demonstrated characteristic mechanical behaviors and deformation patterns in the implant internal connection. These preliminary findings provide descriptive insight into the retrievability of fractured screws and may serve as a basis for future studies with larger sample sizes and clinically relevant fracture models.

To address the issues of displacement and insufficient positional stability observed in the clinical use of the PROPEL Mini stent, this study investigates the influence of different biodegradable materials on the mechanical properties of the stent under the constraint of a fixed monofilament braided closed-loop geometry. Finite element analyses are conducted using Abaqus/Explicit to quantitatively evaluate the nonlinear mapping between nominal diameter, axial length, and radial pressure throughout a loading-unloading cycle. The results reveal that while axial behavior is consistent during compression, material-specific plasticity causes irreversible geometric sets in Mg alloy and PLGA models, whereas the PCL stent achieves total elastic recovery to its initial dimensions. During unloading, the Mg alloy stent recovers to a nominal diameter of 28 mm with a reduced axial length of approximately 22 mm, whereas the PLGA stent exhibits a much smaller recovery diameter of 14 mm with an axial length of approximately 23 mm. These post-release configurations directly determine the functional expansion range of the biodegradable stents after implantation. During unloading, the Mg alloy stent provides the highest radial pressure (peak 6.8 kPa) with a functional recovery range up to 26.5 mm, ensuring superior scaffolding stability. In contrast, while PCL achieves the widest recovery (52 mm), its radial pressure is clinically negligible (the maximum value is still less than 165 Pa), and the PLGA model exhibits both insufficient support and a restricted functional recovery limit (13 mm). By using high-strength materials such as Mg alloys, the radial anchoring force of the stent can be effectively enhanced without changing the existing structure, providing a scientific basis for solving clinical displacement problems.

Introduction: The outcome of endodontic microsurgery depends on the integrity of the apical seal and the adaptation of root-end filling materials under functional stresses. The study aims to compare the void volumes and distribution of ProRoot MTA, ERRM, and ERRM combined with Bioceramic sealer under simulated functional loading using micro-computed tomography (micro-CT).

Methods: Forty-four single-rooted mandibular premolars were prepared with 3 mm apical cavities and divided into four groups (n = 11 each): Cavit (Control), ProRoot MTA, ERRM Putty, and ERRM + BC Sealer. Samples were scanned by micro-CT to quantify internal, marginal, and total voids. Each specimen was then subjected to cyclic vertical loading of 20 N for 1,000,000 cycles in a chewing simulator, followed by post-scanning. Pre- and post-loading void volumes and distribution were analyzed and compared statistically (α = 0.05).

Results: Functional loading significantly increased void volumes in all groups (p < 0.05). Control and MTA showed the highest total and marginal voids (p < 0.05), while ERRM and ERRM + BC maintained significantly lower overall and marginal voids. No difference was detected between ERRM and ERRM + BC (p > 0.05). ERRM and ERRM + BC Sealer showed relatively lower marginal-to-internal voids ratios compared to MTA. Material dislodgement occurred only in Cavit and MTA.

Conclusions: ERRM and ERRM + BC sealer groups exhibited favorable marginal adaptation and significantly lower overall void volumes after low-load functional loading compared to MTA and the control. The findings indicate preserved sealing performance and suggest resistance to void formation under simulated occlusal stresses.

Objective: This retrospective study was conducted to evaluate long-term outcomes lcomplication rates of crown restorations supported by different types of endodontic posts and to determine the influence of post material on biological and technical outcomes. Materials and Methods: Clinical and radiographic data from 437 crowned teeth retained by fiber, metallic, or custom-made posts were collected at Qassim University Dental Hospital between August and November 2025. Biological (secondary caries, periapical lesions) and technical (debonding, fracture, chipping) complications were recorded. Kaplan-Meier and life-table analyses were used to estimate complication-free survival, and Cox regression was employed to identify significant predictors (α = 0.05). Results: The mean observation period was 6.76 ± 4.88 years. The overall complication rate was 56.8%. Crowns restored with fiber posts exhibited the lowest complication rate (40.0%) and the highest 15-year cumulative survival (52%), followed by custom-made (38%) and metallic posts (15%). Fiber posts demonstrated a significantly lower hazard of complications than metal posts (HR = 1.70, p = 0.009). Female sex (HR = 1.69, p = 0.001) and mandibular location (HR = 1.36, p = 0.048) were associated with increased risk. Metal-ceramic crowns showed a protective effect compared to ceramic crowns (HR = 0.56, p = 0.001). Conclusions: The type of post significantly affected long-term prognosis of crowned endodontically treated teeth. Fiber posts provided the most favorable outcomes by minimizing catastrophic root fractures, while metallic and custom-made posts demonstrated higher complication hazards. Crown material, arch location, and patient factors further influenced survival outcomes.

As cancer mortality rates rise globally, malignancies have become the second leading cause of death. Recently, efforts have been made to understand the impact of the tumor microenvironment that involves fluid shear forces. Biomechanical stimulation, which uses shear stress to activate mechanosensitive ion channels, e.g., Piezo1, increases calcium influx into the intracellular space and activates T cells. Novel 3D cancer cultures with T cells have been proposed. Such models use cell/scaffold constructs to recapitulate interactions between cells and the extracellular matrix. In addition, flow perfusion bioreactors investigate the impact of fluid shear forces on immune and/or cancer cells. These bioreactors have biosensors that allow monitoring of immune cell activation. Furthermore, they provide a biomimetic environment for the study of the interaction of T cells and cancer cells. Hence, immune checkpoint inhibitors have demonstrated immunotherapeutic efficacy, but a single-target blockade has often proved insufficient. Co-delivery of CCL19 pDNA and the PD-1/PD-L1 interaction inhibitor BMS-1 using RGD-modified nanocarriers targeting tumor integrins enhanced local antitumor immunity. This review highlights recent insights into how fluid shear stress (FSS) regulates cancer progression and immune responses in three-dimensional in vitro models, with a focus on bioreactors and the surface modification of scaffold materials.

Physicochemical modification of titanium implants aims to enhance early osseointegration by improving bioactivity. This study deposited and evaluated an anatase TiO₂ film on clinically relevant sandblasted, acid-etched titanium (Ti-SLA) to enhance in vitro bioactivity and osteogenic responses. An ~8 µm TiO₂-anatase coating was deposited on Ti-SLA by reactive pulsed DC magnetron sputtering. Surface characterization included FE-SEM, helium ion microscopy, and XRD. Wettability and surface free energy (SFE) were evaluated by contact angle analysis. In vitro bioactivity was assessed by hydroxyapatite (HA) formation in twofold-concentrated simulated body fluid (2× SBF). Osteoblast responses were evaluated through cell adhesion, viability, alkaline phosphatase activity, gene expression, and mineralization. The coating produced hierarchical multi-globular microstructures decorated with faceted anatase nanocrystals. Ti-SLA's initial hydrophobicity converted to a superhydrophilic, high-energy surface with increased polar SFE. Homogeneous HA crystallites deposited exclusively on SLA-anatase in 2× SBF. SAOS-2 cells showed enhanced metabolic activity, ALP activity, osteogenic gene upregulation, and improved mineralized matrix, while primary human osteoblasts exhibited increased metabolic activity and calcium deposition. The anatase coating produced a superhydrophilic, high-energy micro-nano surface that accelerates HA formation and enhances osteoblast function in vitro, warranting in vivo validation for early osseointegration.

Over the past decade, endodontic biomaterials have shifted from being passive fillers to bioactive systems that can support repair and regeneration through validated physicochemical and biological mechanisms [...].