Dental Materials最新文献

Objectives: To characterize the polymerization shrinkage strain, shrinkage stress, and Martens hardness kinetics of a self-cured bulk-fill resin composite (STELA Automix) under different bonding protocols, and to compare its behavior with two light-cured bulk-fill composites.

Methods: STELA Automix was evaluated either alone (ST_A) or with its dedicated STELA Primer (ST_A+P_ST), Adhese Universal (ST_A+AU), or Adhese Universal followed by light curing (STA+AU+LCU). Polymerization shrinkage strain (bonded-disk, 60 min, n = 3), shrinkage stress (Bioman II analyzer, 3600 s, n = 3), and Martens hardness (up to 7 days, n = 5) were measured for STELA and two light-cured bulk-fill composites, Filtek One Bulk Fill and SureFil SDR flow (SDR), under equivalent conditions (23 °C). Data were analyzed by one-way ANOVA and Tukey's test (α = 0.05).

Results: All STELA configurations showed higher final shrinkage strain than the light-cured bulk-fill materials (p < 0.05). Final shrinkage stresses ranged from 1.34 to 2.39 MPa, with ST_A + AU yielding the lowest and ST_A + AU + LCU the highest values (p < 0.05). The dedicated STELA Primer advanced shrinkage onset and increased the interval between onset and the maximum shrinkage-strain rate (Δt), indicating an altered early shrinkage-kinetic profile in the bonded configuration. Across the STELA protocols, shrinkage-rate development extended over tens of seconds, while Martens hardness increased gradually over 7 days and ultimately exceeded that of SDR.

Significance: Despite higher polymerization shrinkage strain than the light-cured composites, STELA exhibited slower stress build-up and a prolonged viscoelastic response during early polymerization. The dedicated primer altered the early shrinkage-kinetic profile by increasing Δt, whereas additional light activation compressed this interval. This kinetic profile, which can be modified by formulation and bonding protocol, may be as critical as shrinkage magnitude in shaping interfacial stress development in bulk-fill composites.

Objectives: This study aims to improve the densification and strength of additively manufactured lithium disilicate glass-ceramics (LDGCs) for dental restorations by introducing a β-spodumene-lithium metasilicate (LM)-amorphous silicon dioxide (A-SiO₂)-glass system.

Methods: Precursor slurries with varying ratios of β-spodumene, LM, and A-SiO₂ were shaped using digital light processing and subsequently sintered without applied pressure. The resulting LDGC samples were systematically evaluated in terms of density, porosity, phase composition, microstructure, mechanical properties, fracture morphology, and molding accuracy.

Results: The combined addition of β-spodumene and LM significantly reduced porosity, promoted densification and crystallinity, and produced a uniform interlocked microstructure. In contrast, the introduction of A-SiO₂ facilitated the transformation of LM into lithium disilicate, but increased porosity and defects by impeding densification. The optimized β-spodumene/LM/glass ternary system achieved a maximum flexural strength of ∼332.5 MPa and a fracture toughness of ∼2.3 MPa·m^1/2, while exhibiting hardness and elastic modulus comparable to natural enamel. Moreover, crown manufacturing demonstrated high molding accuracy.

Significance: The synergistic addition of β-spodumene and LM effectively enhances densification and strength in additively manufactured LDGCs, establishing a promising material system for high-load aesthetic restorations.

Objectives: Fractures in all-ceramic restorations remain a relevant clinical complication despite advances in materials and manufacturing. This study aimed to map and critically appraise the available evidence on fractographic analyses of clinically failed all-ceramic prostheses, focusing on fracture origins and reporting quality.

Methods: This scoping review followed JBI guidelines and was registered in the Open Science Framework. Two trained independent reviewers searched LILACS, MEDLINE, EMBASE, Web of Science and Scopus databases. Studies published in English reporting fractographic analyses of clinically failed prostheses were included. Data extraction covered fractographic methods, restoration type, ceramic material, fracture type, and origin location.

Results: Fracture origins were strongly influenced by restoration design and support conditions. In tooth-supported bilayered alumina single crowns, fracture occurred predominantly at the cervical margins, followed by veneer chipping. In tooth-supported bilayered zirconia FDPs, fractures originated mainly at the gingival side of connectors, followed by veneer chipping. In implant-supported zirconia veneered single crowns, fracture origins were identified at screw access holes or at internal angles of the abutment. In bilayered zirconia implant-supported FDPs, veneer chipping was the most frequent fracture type. Significant variability was identified in the quality of published fractographic analyses.

Significance: Despite advances in materials and manufacturing, fractures in all-ceramic restorations remain a clinical challenge, often associated with design or processing factors. The variability in fracture-prone regions highlights the complexity of restoration biomechanics. Improved adherence to fractographic guidelines and closer collaboration with trained fractographers should be included in future studies to enhance the quality and interpretability of fracture analysis.

Background: The treatment of infected bone defects remains challenging due to persistent infection, insufficient local drug delivery, and a disrupted repair microenvironment. Conventional porous titanium (Ti) scaffolds lack antibacterial functionality, while systemic antibiotics often fail to achieve adequate local concentrations. To address these limitations, this study designed a composite scaffold integrating localized sustained-release antibacterial capability and mechanical compatibility.

Methods: A gyroid porous Ti scaffold with ∼74% porosity and ∼0.82 mm pore size was fabricated via selective laser melting. It was subsequently infused with a sodium alginate/gelatin (SG) hydrogel loaded with kanamycin sulfate (KS) at concentrations of 2.5, 5.0, and 10.0 mg/mL, forming Ti@SG + KS2.5, Ti@SG + KS5, and Ti@SG + KS10 composite scaffolds. These were characterized for microstructure, mechanical properties, drug release, antibacterial activity, and biocompatibility through in vitro and in vivo evaluations, including antibacterial and antibiofilm assays, cell-migration and tube-formation tests, subcutaneous implantation, and an infected bone defect model in rats.

Results: The composite scaffolds retained an open gyroid pore structure with mechanical properties suitable for bone repair, exhibiting compressive yield strengths of 27.9-29.2 MPa and elastic moduli of 0.55-0.58 GPa. The Ti@SG + KS10 scaffold demonstrated strong and sustained antibacterial and antibiofilm activity against Escherichia coli and Staphylococcus aureus, promoted collagen deposition, and suppressed excessive inflammation. In a rat infected bone defect model, it effectively eradicated local infection and significantly enhanced trabecular bone formation, with bone volume and maturity markedly exceeding those of the pure Ti control, along with notable systemic biosafety.

Significance: This study successfully developed a multifunctional Ti‑based composite scaffold that provides mechanical support, localized sustained antibacterial release, and osteogenic enhancement. The scaffold effectively addresses key challenges in the repair of infected bone, such as infection control and microenvironment regulation, thereby offering a promising integrated strategy for the clinical management of infected bone defects.

Objectives: To evaluate the antibacterial effects of tricalcium silicate cement-based sealers and epoxy resin-based sealer with planktonic versus multispecies biofilm assays at 0, 28, and 90 days. The physicochemical properties of the tested sealers were also assessed.

Methods: Four root canal sealers were investigated: AH Plus Jet and AH Plus Bioceramic (Dentsply Sirona, Tulsa, OK, USA), BioRoot RCS, and BioRoot Flow (Septodont, Saint-Maur-des-Fossés, France). Film thickness, flow, radiopacity and solubility were assessed in accordance with ISO 6876:2012. Hydration characteristics and functional groups were analysed using X-ray diffraction (XRD) and Fourier transform infrared (FT-IR) spectroscopy. Antibacterial activity was evaluated using a direct contact test (DCT) against planktonically grown Enterococcus faecalis and Fusobacterium nucleatum, as well as a multispecies biofilm assay incorporating E. faecalis, F. nucleatum, Streptococcus oralis, and Porphyromonas gingivalis. Bacterial viability was determined on material aged for 0, 28, and 90 days. Morphological evaluation of sealers and biofilms was performed using scanning electron microscopy (SEM). Data were analysed using one-way and two-way ANOVA with Tukey post hoc tests.

Results: All sealers met the ISO 6876:2012 requirements for setting time, flow, film thickness and radiopacity, but the hydraulic sealers exhibited higher solubility than AH Plus (P < 0.001). Progressive Ca (OH)₂ formation, particularly in BioRoot RCS, was confirmed by XRD and FT-IR over time. In planktonic assays, tricalcium silicate sealers demonstrated significant antibacterial activity against both bacterial species (P < 0.001), whereas AH Plus resin- based sealer showed limited inhibition. However, the multispecies biofilm assay revealed greater bacterial tolerance and reduced antimicrobial effects for all sealers.

Conclusion: Tricalcium silicate sealers exhibited strong antibacterial activity against planktonic bacteria, however, their antimicrobial effects were diminished against multispecies biofilms. These findings highlight the importance of using biofilm-based assays to evaluate the clinically relevant antimicrobial performance of endodontic sealers, aligning laboratory evaluations with the clinical challenges encountered in root canal infections.

Biofilm-associated oral infections, including dental caries, periodontitis, and peri-implantitis, remain fundamentally challenging to manage due to the highly dynamic oral microenvironment and the intrinsic tolerance of multispecies biofilms to conventional antimicrobial strategies. In this context, stimuli-responsive metal-organic frameworks (MOFs) have emerged not merely as drug carriers, but as programmable platforms capable of integrating environmental sensing, on-demand activation, and multimodal antibacterial action. This review critically re-examines smart MOF-based antibacterial systems through the lens of the oral microenvironment, highlighting how pH fluctuations, enzymatic activity, inflammatory redox stress, and biomechanical forces collectively govern MOF stability, activation, and therapeutic performance. We establish oral-specific design principles for stimuli-responsive MOFs, systematically analyze representative MOF families-including ZIFs, Zr-based frameworks, porphyrinic MOFs, and MIL-series materials-and delineate key activation mechanisms driven by pH, enzymes, redox cues, and light. Particular emphasis is placed on the integration of photodynamic therapy (PDT) with controlled antibiotic release, where MOFs enable spatially confined, synergistic disruption of biofilms while mitigating off-target toxicity and antimicrobial resistance. Beyond mechanistic insights, we critically evaluate preclinical evidence across in vitro, ex vivo, and animal models, and identify translational bottlenecks related to biosafety, ion release control, material reproducibility, and clinical deployment in the oral cavity. By bridging oral pathophysiology with materials engineering, this review provides a conceptual and practical framework for the rational design of next-generation, adaptive MOF systems, and offers guidance for prioritizing research directions with the greatest potential for clinical impact in precision antibacterial dentistry.

Objectives: Polyaryletherketones (PAEKs) are widely used in dentistry due to their high biocompatibility, while their physical and mechanical properties are frequently modified using fillers and additives. Effects of these modifications on biocompatibility and biofilm formation remain unclear. This study investigated the influence of different PAEK compositions on the quantity and composition of biofilms.

Methods: Five PAEKs (unfilled PEEK, filled PEEK, pressed PEEK, PEKK, and AKP) and reference materials (titanium, zirconium dioxide, PMMA) were polished to Ra values below 0.2 µm to control for topographical effects. Surface morphology and composition were determined by scanning electron microscopy and wavelength-dispersive X-ray spectroscopy on an electron microprobe (WD-EPMA). Surface free energy (SFE) was analyzed by contact angle measurement. Custom-made intraoral splints with mounted material specimens were worn by 20 participants for 24 h. Biofilm formation was analyzed using microscopy and qPCR. Two PEEK types (filled and unfilled) underwent additional 24-hour exposures by six participants and were analyzed for microbial differences. Additionally, filled and unfilled PEEK were compared to titanium in CCK-8 assays using human fibroblasts.

Results: All materials exhibited homogeneous surface morphology. SFE was significantly higher (p < 0.0005) for all materials compared to titanium, except for zirconium dioxide. Filled PEEK showed increased biofilm formation compared with unfilled PEEK in vitro and in vivo (p < 0.0001), while biofilm composition remained unchanged. Only PEEK containing TiO₂ was associated with increased biofilm formation, without improving fibroblast viability.

Significance: TiO₂ in PEEK increased biofilm formation without enhancing fibroblast viability, indicating that material fillers can affect microbial colonization independently of cellular biocompatibility.

Objective: To enhance the stability of resin-dentin bonding interface, this study aimed to develop a multifunctional SACP-PEP/TMC film made up of silanized amorphous calcium phosphate (SACP), amelogenin-derived peptide PEP-QP5, and trimethyl chitosan (TMC) integrating biomimetic remineralization, collagenase suppression, and bacterial inhibition effect, and explore the film-based application under both etch-and-rinse and self-etch strategies.

Methods: The SACP-PEP/TMC film was fabricated by solution casting for the evaluation of its morphology, swelling, release behavior, and cytotoxicity. Recombinant collagen and demineralized dentin models were constructed to evaluate its biomimetic remineralization capacity. Live/dead staining, scanning electron microscopy were used to assess the bacterial inhibition effect against Streptococcus mutans. Micro-shear bond strength (μSBS), microleakage, and in-situ zymography were used to evaluate the resin-dentin bonding performance and durability, which were further evaluated in vivo using a rat model combined with Micro-CT and histological analyses.

Results: A homogeneous SACP-PEP/TMC film with a thickness of approximately 4-5 μm was successfully fabricated. The film rapidly swelled and dispersed within the adhesive and enabled sustained release of Ca^2 +, PO₄^3- and PEP-QP5 for up to 3 months after light curing. It effectively induced biomimetic mineralization while significantly inhibiting Streptococcus mutans. Improved μSBS, reduced interfacial microleakage, and suppressed endogenous matrix metalloproteinase activity were observed, accompanied by significantly increased immediate and long-term resin-dentin bond strength in vitro and in vivo.

Significance: The multifunctional SACP-PEP/TMC film improved resin-dentin bonding durability significantly by integrating biomimetic remineralization, collagenase suppression, and bacterial inhibition effect, suggesting the film-based application form a promising strategy for developing durable dentin bonding materials.

To overcome the limitations of the presently existing preformed crowns on primary teeth in terms of esthetics, mechanical properties, and longevity in the repair of extensive defect areas, an innovative glass fiber-reinforced resin preformed crown on primary teeth has been created and tested in the present research. The material is based on a copolymer system of modified vinyl-epoxy resin and acrylic resin, incorporated with inorganic fillers such as zirconia and reinforced with glass fibers, forming a glass fiber-reinforced vinyl-epoxy polymer (GF-VEP). The in vitro data proved that the physicochemical characteristics (water sorption, solubility, and hardness) and biocompatibility (cytotoxicity and hemolysis) of the material were in line with appropriate industry requirements. GF-VEP crowns had significantly greater compressive and fatigue strength than clinically used preformed resin crowns but less than preformed metal crowns that did not fail under the maximum applied load, when subjected to simulated intraoral conditions. The wear resistance of GF-VEP crowns was not statistically different than preformed resin crowns and significantly lower than preformed metal crowns. GF-VEP crowns also showed significantly higher bonding strength than preformed resin crowns, and no marginal leakage recorded. Even though the bonding strength of preformed metal crowns was not significantly different compared to GF-VEP crowns, dye microleakage was noted at the bonding interface. In general, the GF-VEP crown has a promising overall performance, meeting or exceeding the standards of the existing clinical products, shows potential as an esthetic, reliable, and scalable restorative option to large defects on primary teeth.

Objective: Thiourethanes (TU) improve mechanical properties and depth of cure in dental materials. This study investigated whether these benefits are maintained under light attenuation conditions, when TUs are combined with different photoinitiators, and used in cements cured under different ceramic thicknesses.

Methods: BisGMA/UDMA/TEGDMA (50/30/20 wt%) were combined with 0 or 20 wt% TU. Camphorquinone/amine (CQ/EDMAB), BAPO, or Ivocerin were used as photoinitiators. Polymerization kinetics and light transmission were monitored by near-IR spectroscopy during photoactivation (320-500 nm, 1580 mW/cm², 300 s, n = 3) through 0, 0.5, and 1.5 mm ceramic. Irradiance and photoinitiator consumption were evaluated by UV-Vis. Data were analyzed by three-way ANOVA/Tukey's test (α=0.05).

Results: Conversion increased with TU under most conditions (p < 0.001), but decreased as a function of ceramic thickness (p < 0.001), due to reduced irradiance. TU only reduced Rp_max when combined with CQ (p < 0.05). Ivocerin achieved the highest conversion at the clinically relevant 40-s exposure, while CQ produced the highest final DC at 300 s. Shorter wavelengths were more attenuated with increasing ceramic thickness (p < 0.001). Photoinitiator consumption was highest for Ivocerin (88%), followed by BAPO (74%) and CQ (60%).

Conclusion: TU improved conversion under all conditions, and led to at least partial recovery of the loss in conversion observed under light attenuation conditions under different ceramic thickness, compared with non-TU controls. That recovery was greater when TU was combined with alpha-cleavage type initiators.

Significance: Combining TU with alternative photoinitiators improves curing under light attenuation.