Self-curing polymethyl methacrylate is widely used for provisional restorations, retainers and denture repairs, but its lack of antibacterial activity favors bacterial colonization. Magnesium oxide nanoparticles exhibit broad antibacterial effects through the generation of reactive oxygen species. This study evaluated the influence of mechanochemically synthesized magnesium oxide nanoparticles on the mechanical properties of self-curing polymethyl methacrylate and on its antibacterial activity against Actinomyces israelii, Porphyromonas gingivalis, Capnocytophaga gingivalis, Prevotella intermedia, Streptococcus sanguinis, Streptococcus sobrinus, Eikenella corrodens and Fusobacterium nucleatum sensu stricto. Nanoparticles (1, 3 and 5 wt%) were incorporated into the polymer powder and polymerized. Flexural strength, elastic modulus, water sorption and solubility were determined. Antibacterial activity was assessed in broth cultures and quantified by optical density at 595 nm, with viability confirmed on agar. Nanoparticle incorporation provided in vitro antibacterial activity while partially reducing mechanical strength. These results suggest a targeted use of modified polymethyl methacrylate for applications prioritizing.
This study aimed to develop a novel cassava starch (CS)-based impression material and evaluate its physicochemical properties in comparison with conventional alginate. CS impression material was developed by combining CS with fillers and setting modifiers. Novel impression material was characterized using Fourier transform infrared spectroscopy and moisture content determination. Five water-powder (W/P) ratios (0.52, 0.60, 0.64, 0.68, 0.72) were assessed; W/P 0.64 was optimal, yielding the shortest setting time (9.33±0.51 min) with Rate 1 surface reproducibility. At this ratio, viscosity, tear strength, dimensional stability, elastic recovery, and compressive strength were compared with alginate (Tropicalgin, Zhermack, Italy; n=6). CS material demonstrated superior compressive strength (0.71 vs. 0.43 MPa, p=0.006), lower viscosity (2.20×103 vs. 7.73×103 cP, p<0.001), and markedly less dimensional change at 60 min (1.01 vs. 7.50 mm, p<0.001). Alginate exhibited significantly better elastic recovery (94.33% vs. 51.67%, p<0.001). Independent t-tests were applied (p<0.05).
The restoration of esthetics in dental treatment is essential for patient satisfaction, and accurate color reproduction is critical. Universal-shade resin composites, which eliminate the need for shade selection, have attracted attention; however, their color-matching ability to natural enamel remains unclear. This study evaluated the color-matching of universal-shade resin composites to human enamel compared with conventional A2-shade resin composites and investigated the direction of hue changes. Universal-shade resin composites and conventional A2-shade resin composites were placed on flattened human enamel surfaces with glycerin, and color changes were measured. No significant differences in L* values were observed among groups. The a* values significantly decreased in the OMNICHROMA Flow and DP-022 M flow groups, while b* values decreased in all groups except Clearfil Majesty ES Flow (A2). These findings suggest that the color-matching performance of universal-shade resin composites varies depending on the material.
This in vitro study evaluated the effects of a sodium-fluoride varnish, two surface pre-reacted glass-ionomer (S-PRG)-containing agents, and an experimental glycerol-stabilized calcium phosphate cluster (GCPC) gel on dentin permeability using a custom hydraulic conductance apparatus. Horizontal 1-mm coronal dentin disks were prepared from extracted human molars, conditioned with 2% citric acid, and randomized to ClinPro Fluoride Treatment, PRG Barrier-Coat, PRG Pro-Care Gel, experimental GCPC gel, or distilled-water control (n=10/group). Hydraulic conductance was calculated at 3 psi from the time required for 50 µL of water to pass through each specimen. ClinPro and PRG Barrier-Coat significantly reduced permeability after the first post-treatment evaluation, whereas ClinPro and both PRG agents produced near-zero values after the second evaluation. GCPC yielded a moderate but significant reduction. Scanning electron microscopy findings were consistent with progressive dentinal tubule occlusion.
This study evaluated the bonding performance and durability of a novel long-chain silane, 8-methacryloxyoctyl trimethoxysilane (8-MOTS), on zirconia surfaces. Specimens were treated with varying concentrations of 8-MOTS (0.1-4.0%) and compared with 3-(trimethoxysilyl)propyl methacrylate (3-TMSPMA) and a commercial silane primer. All zirconia surfaces underwent airborne-particle abrasion with alumina to simulate a clinically common surface treatment. Shear bond strength (SBS) was assessed after water storage (37ºC, 24 h) or boiling (100ºC, 16 h) as a severe hydrothermal screening method. The most favorable bonding performance was observed with 8-MOTS at 1.0% and 1.5%, maintaining SBS values ≥20 MPa after boiling. Failure-mode analysis and scanning electron microscopy indicated greater luting-agent retention and more combined failures in high-performing groups. Within the present alumina-abrasion and MDP-containing bonding protocol, 8-MOTS at 1.0-1.5% showed favorable durability.
This study developed a polymer-infiltrated ceramic network (PICN) with dentin-like mechanical properties for tooth restoration, and explored its internal stress transmission mechanisms under load using digital image correlation (DIC). A porous sodium aluminum silicate powder scaffold was fabricated and vacuum-infiltrated with resin to produce experimental PICN (EXP). The mechanical properties of EXP, Enamic, Emax, zirconia were assessed using Vickers hardness and three-point bending tests, shear bond tests, combined with DIC to observe their corresponding stress distribution and transmission path. The EXP with 30% porosity exhibited a flexural strength of 192.90 MPa, a shear bond strength of 23.35 MPa, a Vickers hardness of 2.75 GPa and an elastic modulus of 8.19 GPa which is comparable to demineralized dentin 8.47 GPa. The DIC revealed a more homogeneous strain distribution in the EXP compared with other materials, indicating a promising alternative for CAD/CAM dental restorations.
This in vitro study aimed to quantitatively evaluate residual monomer release at different time points from specimens with different thicknesses fabricated from five commercially available 3D-printed permanent crown resins manufactured using additive manufacturing technology. Specimens with thicknesses of 2 mm and 4 mm were prepared from five 3D-printed permanent crown resins [BEGO VarseoSmile Crown plus (BVS), NextDent C&B MFH (ND), Formlabs Permanent Crown Resin (FL), Saremco print CROWNTEC (SC), DentaFab PowerResins C&B (DF)] and from GC Cerasmart270 as a reference material (24 groups, n=8). The specimens were stored in a 75% ethanol/water solution for 1 week and 1 month. The elution of triethylene glycol dimethacrylate (TEGDMA), urethane dimethacrylate (UDMA), bisphenol A-glycidyl methacrylate (Bis-GMA) and 2-hydroxyethyl methacrylate (HEMA) was analyzed using high-performance liquid chromatography. Higher monomer release was observed for Bis-GMA and TEGDMA, particularly in the BEGO group. Increased specimen thickness was associated with higher TEGDMA release in the BVS group and higher Bis-GMA and TEGDMA release in the ND group. Prolonged storage duration generally increased Bis-GMA and TEGDMA release levels, particularly in the BVS, SC, and DF groups. Thickness- and time-dependent increases in UDMA and HEMA release were also observed in certain groups. These findings suggest that residual monomer release may be influenced by material type, specimen thickness and storage duration under the present experimental conditions.
This study examined the effectiveness of two newly released grinding materials in Japan on two types of zirconia with different yttria contents. Rotary cutting tools may be used for occlusal adjustment of single zirconia crowns. Grinding and polishing are then required. Simplified zirconia crowns with 3Y and 5Y yttria contents were manufactured and used as samples. After occlusal adjustment, the surface roughness and gloss of samples were measured at each stage using grinding and polishing materials. No significant differences were observed in surface roughness between 3Y and 5Y zirconia. The use of newly released grinding materials was effective for the surface treatment of zirconia. However, the surface roughness required to omit compound grinding was not achieved. Additionally, omitting either of the two grinding material processes increased variability in surface roughness after final grinding. Compound grinding is strongly recommended after occlusal adjustment of monolithic all-ceramic crowns following their installation.
The purpose of this study was to evaluate the stress distribution caused by different CAD-CAM abutments in immediate and delayed loading procedures in the maxillary central tooth area. Six different hybrid abutment models [titanium (control), zirconia, lithium disilicate, polymer-infiltrated hybrid ceramics, polyetheretherketone, and polymethyl methacrylate] were created. The von Mises stress values of the implant, Ti-base, implant screw, abutment, and crown, as well as the maximum and minimum principal stress values formed in the cortical and trabecular bone and the bone resorption risk index were evaluated. The highest stress values were observed in the implant, Ti-base, bone, and crown in the polymethyl methacrylate abutment, while the lowest values were observed in the zirconia abutment. The von Mises stress values in the immediate loading group were found to be lower than those in the delayed loading group. The bone resorption risk has been found to be higher in immediate loading.
The objective of the work was to prepare dual-functional TiO2-containing phosphate glasses to integrate ion-releasing ability and photocatalytic activity into a single material system. The glasses were prepared using the liquid phase method. The obtained glasses exhibited an amorphous structure and were composed of orthophosphate and pyrophosphate groups, which can therefore be classified as phosphate invert glasses. Structural analyses showed that titanium existed in both TiO4 tetrahedral and TiO6 octahedral coordination environments. The aging process promoted the formation of TiO6-rich phases on the glass surface. Glasses that were heat-treated at 600°C exhibited partial crystallization of anatase TiO2 while retaining the amorphous phosphate glass matrix. The heat-treated glass exhibited photocatalytic activity under UV irradiation, as confirmed by methylene blue degradation, while maintaining sustained ion release. Therefore, TiO2-containing phosphate glasses exhibit dual functionality, combining therapeutic ion release and photocatalytic activity. The properties of the obtained glasses may stimulate beneficial physiological responses and provide antibacterial effects, supporting their potential application as dual-functional dental biomaterials.
Composite granules of β-tricalcium phosphate (βTCP) derived from limestone were fabricated by mixing with polyacrylic acid (PAA) for potential bone substitute applications. Samples with varying ratios were evaluated using X-ray diffraction (XRD), Fourier-transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM), porosity analysis, and diametral tensile strength (DTS) testing. XRD confirmed the crystalline nature of βTCP, with peak intensities increasing as βTCP content increased. FTIR showed C=O stretching of -COOH and symmetric COO- vibrations, with νs(COO-) bands appearing in composites, indicating interactions between PAA and βTCP through Ca2+-carboxylate coordination. SEM revealed a porous structure in the composite granules, with pore size increased with βTCP content. Porosity was higher in all composite granules compared to PAA granules, while DTS values improved with increasing βTCP, indicating enhanced mechanical strength. In conclusion, composite granules were successfully fabricated by mixing βTCP derived from limestone with PAA, exhibiting promising characteristics as synthetic bone substitutes.
The increasing prevalence of denture use, particularly among the elderly population, necessitates effective strategies against Candida-containing polymicrobial biofilms. This study investigated novel temporary (biocompatible hydrogel) and permanent (sealant) denture coatings designed to selectively inhibit associated pathogens. Seven biomaterials were screened using minimum inhibitory concentration (MIC) assays against Candida albicans, Fusobacterium nucleatum, and Streptococcus mutans. Coatings were applied to acrylic surfaces and evaluated for physicochemical properties and antimicrobial efficacy using biofilm models and colony-forming unit (CFU) counting. Results demonstrated that poly(ethylene glycol) diacrylate / titanium dioxide (PEGDA/TiO2) and Sealant/TiO2 formulations exhibited significant, selective antimicrobial activity. This efficacy is attributed to altered surface hydrophilicity and the specific mechanisms of incorporated agents. These findings underscore the potential of biocompatible, bio-selective coatings in preventing denture-associated infections. Additional research involving a broader spectrum of oral microbes is required to further validate these preventive applications.
This study evaluated the monomer conversion (DC), surface microhardness, elemental release, and cytotoxicity of experimental dental sealants containing monocalcium phosphate monohydrate (MCPM), strontium/fluoride-bioactive glass nanoparticles (Sr/F-BAGs), and ε-polylysine. Experimental sealants with (TS1) and without additives (TS0) were compared to commercial sealants (Clinpro and BeautiSealant). DC was measured after light-curing for 40 s. Surface microhardness and elemental release in deionized water were determined after 4-week water storage. Cell viability of the extract was also examined. TS1 exhibited a DC of 82%, significantly higher than commercial materials (65-73%, p<0.05). Surface microhardness of TS1 (14.8 VHN) was comparable to commercial sealants (p>0.05). TS1 released Ca, Sr, and P ions, while commercial materials released mainly fluoride. All materials showed >70% cell viability. The experimental dental sealant demonstrated satisfactory polymerization and mechanical properties with enhanced multi-ion release, suggesting potential for improved bioactivity of the material to help prevent caries associated with restoration and sealant (CARS).
Titanium implants require surface modifications to overcome biological inertia and enhance osteointegration. Macrophage polarization is critical in regulating osteogenesis which affects inflammation and tissue repair. Strontium has been shown to enhance bone formation, and Sr2+ ions have also been found to influence immune responses and inflammation, suggesting potential applications in bone repair and regeneration. Our research utilized phase-transited lysozyme (PTL) surface modification to immobilize Sr2+ ions within the PTL coating, thereby obtaining two distinct morphological coatings: Sr-incorporation PTL-nanofilm (PSR-nanofilm) and Sr-incorporation PTL-coating (PSR-coating). Through a combination of in vitro and in vivo experimental approaches, this study demonstrated that PSR-coating implants with rough titanium surfaces enhance osteogenesis compared to PSR-nanofilm implants. This effect is attributed to their ability to polarize macrophages into the pro-inflammatory M1 phenotype during the early stage of implantation, followed by a transition to the anti-inflammatory M2 phenotype at a later stage via the sustained release of Sr2+.
This study focuses on optimizing Biodentine by incorporating zinc oxide nanoparticles (ZnO NPs) loaded with the antimicrobial agent cefixime to enhance both its mechanical properties and antibacterial efficacy. ZnO NPs were synthesized using zinc acetate dihydrate and oxalic acid via the sol-gel method, and cefixime was loaded through solvent-mediated techniques. Characterization via Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), scanning electron microscopy (SEM), UV-visible spectrophotometry (UV-Vis), and zeta potential confirmed the successful formation and stability of the nanoparticles. These drug-loaded NPs were then integrated into Biodentine for mechanical and structural evaluation. Results showed improved surface area, microhardness (Vickers), compressive strength, and reduced solubility without significantly altering the setting time. Energy dispersive X-ray spectroscopy (EDX) and SEM analyses confirmed uniform nanoparticle dispersion and elemental composition, while pH remained within safe limits. The modified Biodentine demonstrated superior performance and antimicrobial potential, making it promising for long-term dental restorations. The study concludes that ZnO-cefixime nanocomposite Biodentine offers dual advantages of mechanical strength and infection control.
Fucoidan is a sulfated polysaccharide from brown algae with potential as a marine-derived biomaterial for oral healthcare. This study compared crude fucoidan, purified fucoidan, and low-molecular-weight fucoidan (LMF) to clarify the relationship between physicochemical properties and biological activity. Iodine content was quantified by mass spectrometry, collagenase inhibition against MMP-8 and MMP-13 and antioxidant capacity were evaluated using biochemical assays, and cellular responses were assessed in oral squamous carcinoma (SAS) cells and normal fibroblasts. Among the preparations, LMF showed the highest iodine content and the strongest inhibition of collagenases and reactive oxygen species. Fucoidan selectively reduced the viability of SAS cells while sparing fibroblasts. RNA sequencing revealed activation of apoptosis-related pathways and suppression of survival signaling in SAS cells, whereas fibroblasts exhibited stress-adaptive transcriptional profiles. These results indicate that LMF exerts selective cytotoxic and tissue-protective effects, supporting its application as a functional dental biomaterial.
Poly(ɛ-caprolactone) (PCL) is widely used in bone tissue engineering but lacks intrinsic bioactivity. In this study, carbonate substituted hydroxyapatite (CHA) was incorporated into PCL using direct powder extrusion (DPE) three-dimensional (3D) printing to fabricate scaffolds with controlled CHA contents. Structural and thermal analyses confirmed that CHA retained its apatite crystal structure and acted as a mild nucleating agent without significantly altering PCL thermal behavior. Micro-computed tomography (micro-CT) combined with multi-scale spatial statistical analysis revealed scale-dependent particle distribution, with near-random arrangements at the nearest-neighbor scale and increasing mesoscale clustering at higher CHA contents. Mechanical testing showed that compressive and tensile elastic moduli increased with CHA addition up to 10 wt%, followed by a decrease at higher loadings. Annealing enhanced elastic modulus by improving interlayer bonding and internal structural homogeneity. These findings demonstrate that CHA content and spatial particle organization govern the mechanical performance of DPE 3D printed PCL-CHA scaffolds for bone tissue engineering.
Induced pluripotent stem cells (iPSCs) are a promising source for regenerative medicine due to their multilineage differentiation ability. We established a feeder-free xeno-reduced workflow to merge iPSC-derived mesenchymal stem cells (MSCs) and endothelial cells (ECs) into uniform hybrid spheroids for bone repair. iPSCs were differentiated into MSCs (CD73+/CD90+/CD105+; osteogenic, adipogenic, and chondrogenic) and ECs using a defined kit with brief fetal bovine serum exposure, yielding CD31+ cells that formed tube-like networks on the Matrigel. MSCs and ECs (5:1) were seeded in low-adhesion MicoCell® microwells, self-assembled within 4 h into hundreds of compact size-controlled spheroids, and maintained for 72 h under serum-free conditions. After clear unobstructed brain/body imaging cocktails and computational analysis (CUBIC) clearing and confocal immunofluorescence, CD90 and CD31 signals showed a distinct spatial organization within the three-dimensional structures, indicating the coexistence of both lineages. Notably, lumen formation was not observed at this stage. Overall, our feeder-free single-source system provides a reproducible platform for subsequent vascular maturation studies.
Various adhesive systems are available for direct resin-composite restorations. However, few studies have evaluated the relationship between environmental factors and the bond strength of universal adhesives (8th generation). This study evaluated the influence of the bonding environment on the bond strength to bovine teeth by comparing four universal adhesives with two two-step self-etch adhesives (2-SEA). Bonding was performed under simulated laboratory, rubber-dam, and intraoral conditions with temperature and relative humidity of 23°C and 50%; 30°C and 50%; and 30°C and 95%, respectively. The micro-tensile bond strengths of the adhesives were not significantly different between the rubber-dam and laboratory conditions. However, the bond strength values for three universal adhesives were significantly lower under intraoral conditions. This study suggested that high-humidity conditions, such as in the oral cavity, may affect the bonding performance of universal adhesives. However, the influence of humidity might be limited when using 2-SEA or under rubber-dam isolation.
This study aims to evaluate the bacterial activity of Barangan peel against Streptococcus mutans (S. mutans) using in silico and in vitro methods. In silico conducted with AutoDock 4.0 evaluated ligand binding to GtfB (PDB ID: 3AIB), SwissADME, ProTox-II, and PASS online assessed pharmacokinetic, toxicity, and biological activity profiles. Antibacterial activity of Barangan peel at 10%, 20%, 35%, and 50% concentrations against S. mutans was determined using agar assays. The inhibition zones and colony count data were analyzed using one-way ANOVA (p≤0.05). Results showed Barangan peel phytochemical has low toxicity (Class 5-6, LD50 >2,000 mg/kg) and high biological potential for non-phenolic terpenoids (Pa=0.405). Cyclopropa stigmat steroid has the strongest affinities (-8.00 kcal/mol). The minimum inhibitory concentration (MIC) was at a 10% concentration, while the inhibition zone diameter and colony count showed significant differences (p<0.05) for all concentrations. Barangan peel phytochemicals exhibited favorable toxicity profiles and potent inhibitory activity against S. mutans.
