The current study attempted to investigate the effect of hydroxyapatite nanofibers (HANFs) added in different percentages upon the qualities of glass ionomer cement (GIC): fracture toughness, vickers microhardness and fluoride release. Synthesis and characterization of hydroxyapatite nanofibers were carried out before being added to the powder of high-viscosity conventional GIC in three varied weight ratios (1, 3 and 5%) resulting into 3 experimental groups which were next compared with basic GIC as a control group. Fracture toughness, Vickers microhardness and fluoride release on day1 and day 7 were evaluated. Results indicated significant improvement in fracture toughness, microhardness and fluoride release of GIC modified by hydroxyapatite nanofibers at varied tested ratios and this increase was directly proportional to their ratio of addition. According to these findings, glass ionomer cement modified with hydroxyapatite nanofibers in varying proportions could be a dependable restorative material with enhanced fracture toughness, microhardness and fluoride release.

Molecular biotechnology for the biodegradation of organofluorine compounds.

ObjectivesDemineralization of enamel is a major challenge during and after fixed orthodontic treatment. Fluoride can strengthen the enamel and reduce the occurrence of white spot lesions (WSLs). Current fluoride-releasing products exhibit a short-term release due to initial burst effect, which severely limits clinical effectiveness. O-rings are orthodontic elastomeric ligatures used to support the attachment of arch-wire to each bracket. This study aimed to develop a simple method to coat the O-rings for long-lasting fluoride release.MethodsCalcium fluoride (CaF2) was coated on the commercial O-rings via a dip and dry method using a coating medium composed of a solution of polycaprolactone (PCL) with CaF2 microcrystals. To optimize the fluoride release, the coating media with different concentrations of PCL (2.5%, 5%, and 10%) solution were applied, and the fluoride release was measured for 7 weeks. The morphology and elemental abundance of the coatings were characterized by energy-dispersive X-ray spectroscopy. The resilience of the modified O-rings was evaluated by a standard tensile program.ResultsA thicker coating with a higher elemental abundance of fluoride was achieved by increasing the PCL concentration in the coating medium. The average fluoride release rates of the 2.5%, 5%, and 10% groups in the seventh week were 0.69 μg F−/ring/day, 6.54 μg F−/ring/day, and 6.97 μg F−/ring/day, respectively. 5% and 10% groups showed long-term and linear release within the therapeutic range, while the 2.5% group fell below the range from the sixth week.ConclusionOur study demonstrated Ca-F O-rings displayed sustained fluoride release under in vitro conditions, indicating potential clinical relevance for reducing WSLs during orthodontic treatment. This work represents an early-stage feasibility study and warrants further validation with larger-scale and in vivo conditions.

Perfluorooctane sulfonate (PFOS), a persistent and bioaccumulative perfluoroalkyl substance, poses significant environmental and human health risks due to the extraordinary stability of its C–F bonds. Conventional remediation strategies largely fail to achieve mineralization, instead transferring contamination or producing secondary waste streams. In this study, we investigate neutron irradiation as a potential destructive approach for PFOS remediation in both solid and aqueous matrices. Samples were exposed to thermal neutrons (flux: 3.2 × 109 n·cm−2·s−1, 0.0025 eV) at the Argonauta reactor for 6 h. Raman and FTIR spectroscopy revealed that PFOS in powder form remained largely resistant to degradation, with only minor structural perturbations observed. In contrast, aqueous PFOS solutions exhibited pronounced spectral changes, including attenuation of C–F and S–O vibrational signatures, the emergence of carboxylate and carbonyl functionalities, and enhanced O–H stretching, consistent with radiolytic oxidation and partial defluorination. Notably, clear peak shifts were predominantly observed for PFOS in aqueous solution after irradiation (overall displacement toward higher wavenumbers), whereas in powdered PFOS the main spectral signature of irradiation was the attenuation of CF2 and S–O related bands with comparatively limited band relocation. To evaluate the biological relevance of these structural alterations, cell viability assays (MTT) were performed using human umbilical vein endothelial cells. Non-irradiated PFOS induced marked cytotoxicity at 100 and 50 μg/mL (p < 0.0001), whereas neutron-irradiated PFOS no longer exhibited significant toxicity, with cell viability comparable to the control. These findings indicate a matrix-dependent response: neutron scattering in solids yields negligible molecular breakdown, whereas radiolysis-driven pathways in water facilitate measurable PFOS transformation. The cytotoxicity assay demonstrates that neutron irradiation promotes sufficient molecular degradation of PFOS in aqueous media to suppress its cytotoxic effects. Although complete mineralization was not achieved under the tested conditions, the combined spectroscopic and biological evidence supports neutron-induced radiolysis as a promising pathway for perfluoroalkyl detoxification. Future optimization of neutron flux, irradiation duration, and synergistic catalytic systems may enhance mineralization efficiency. Because PFOS concentration, fluoride release (F−), and TOC were not quantified in this study, remediation was assessed through spectroscopic fingerprints of transformation and the suppression of cytotoxicity, rather than by mass-balance mineralization metrics. This study highlights neutron irradiation as a promising strategy for perfluoroalkyl destruction in contaminated water sources.

White spot lesions (WSLs) are characterized by enamel demineralization. Minimally invasive treatments using infiltrating resins, such as the commercially available Icon®, are recommended. The need for such treatments justifies ongoing research into developing materials that can address existing limitations regarding strength, durability, and biocompatibility. This study aimed to synthesize and characterize four novel nanobiomaterials by evaluating their physicochemical properties and biocompatibility compared to the commercial material Icon®. The recipes for the experimental nanobiomaterials NB3, NB6, NB3F, and NB6F contain varying proportions of TEGDMA, UDMA, HEMA, Bis-GMA, and HAF-BaF2 glass. Mechanical and physicochemical characteristics were evaluated, such as flexural strength, measured using the three-point test; water absorption and solubility; fluoride release; polymerization conversion; and residual monomers, assessed using High-Performance Liquid Chromatography (HPLC). In vitro cell viability was assessed via colorimetry using human dysplastic oral keratinocytes (DOKs). NB6 and NB6F demonstrated the greatest polymerization potential. NB3 exhibited the lowest water absorption and solubility due to its hydrophobic nature. Additionally, the inclusion of UDMA enhanced the strength and elasticity of NB3 when compared to NB6. Among the samples with fluoride additives (NB3F and NB6F), the highest fluoride release on day 7 occurred with the material lacking UDMA. In contrast, the NB3F sample containing UDMA released the least amount of fluoride on the same day. In quantitative terms, NB3 and NB6F exhibited the lowest levels of residual monomers, whereas NB6 showed the highest levels. Both NB3 and NB6 were significantly better tolerated by the cells, showing higher cell viability compared to the commercial material Icon®. The materials' mechanical and physicochemical properties varied with component proportions, enabling identification of a suitable formulation for targeted clinical applications. Biocompatibility tests showed that the experimental NB3 and NB6 were better tolerated than Icon®. Furthermore, the incorporation of filler particles improved the mechanical strength of the experimental nanobiomaterials.

Evaluation of Fluoride Release and Antibacterial Activity of Four Fluoride-Releasing Restorative Materials: An in Vitro Study

Enhanced physicochemical properties and mineral precipitation in experimental glass ionomer cements containing fluoride-doped calcium phosphates and zinc-polycarboxylate bioactive glass.

Background: Glass ionomer cement (GIC) is a widely used dental material known for its chemical adhesion to tooth structure, fluoride release, and biological compatibility, making it valuable across multiple dental disciplines. Since its development in the early 1970s, continuous modifications have expanded its clinical and interdisciplinary applications. Aim: This article aims to review the composition, properties, clinical indications, limitations, and interdisciplinary relevance of glass ionomer cement in dentistry, dental laboratories, and allied healthcare practice. Methods: A narrative review approach was employed, synthesizing existing scientific literature and clinical evidence related to the chemistry, setting mechanism, manipulation techniques, and clinical performance of conventional and modified glass ionomer cements. Results: Glass ionomer cement demonstrates reliable chemical bonding to enamel and dentin, sustained fluoride release with anticariogenic effects, and favorable biological responses. Advancements such as resin-modified, metal-reinforced, and high-viscosity formulations have improved handling characteristics, early strength, and moisture tolerance. However, limitations remain, including lower fracture resistance, reduced abrasion resistance, and esthetic constraints in high-stress or highly visible areas. Conclusion: Glass ionomer cement remains an essential restorative and preventive material when appropriately selected according to clinical demands. Its dentin-like properties, fluoride-mediated protection, and compatibility with interdisciplinary care continue to support its significant role in modern dental practice.

Restoration of primary teeth is a fundamental component of pediatric dental care, as primary dentition plays a critical role in mastication, speech development, esthetics, and the maintenance of arch integrity for the eruption of permanent teeth. Dental caries remains one of the most prevalent chronic diseases in children worldwide, making the selection of appropriate restorative materials essential for achieving durable and biologically acceptable outcomes. This narrative review aims to evaluate the restorative options available for primary teeth in pediatric dentistry, with emphasis on their clinical performance, advantages, and limitations. Due to the anatomical and histological differences between primary and permanent teeth—such as thinner enamel and dentin, larger pulp chambers, and shorter functional lifespan—restorative material selection in primary teeth requires specific considerations. Traditional materials, including dental amalgam, have demonstrated long-term durability and moisture tolerance; however, their use has declined due to esthetic demands and concerns regarding mercury exposure. Glass ionomer cements and their modified forms offer chemical adhesion to tooth structure, fluoride release, and cariostatic properties, making them particularly suitable for children at high caries risk, despite their relatively lower mechanical strength. Resin-based materials, such as composite resins, compomers, giomers, and ormocer-based systems, provide superior esthetics and acceptable mechanical properties, but their clinical success is highly dependent on proper isolation and technique sensitivity. Full-coverage restorations, including stainless steel crowns, veneered crowns, prefabricated zirconia crowns, and newly developed polymer-based crowns, are recommended for extensively damaged primary teeth, especially following pulp therapy. Stainless steel crowns remain the gold standard for posterior primary teeth due to their durability and cost-effectiveness, whereas zirconia and aesthetic crowns offer improved esthetic outcomes with certain limitations related to tooth preparation and retention. Recent advancements in restorative materials and digital technologies, such as CAD–CAM-fabricated crowns, have expanded treatment options in pediatric dentistry. In conclusion, no single restorative material fulfills all clinical requirements. The selection of restorative options for primary teeth should be individualized based on the child’s age, caries risk, tooth location, functional demands, esthetic expectations, and level of cooperation. Appropriate material selection contributes significantly to the long-term oral health and overall well-being of pediatric patients.

Background: Preservation of tooth structure is a key principle in pediatric dentistry, where restorative materials must balance mechanical strength with the preservation of pulp vitality and minimally invasive techniques. The aim of this in vitro study, as it relates to pediatric dentistry, was to investigate the flexural strength of common composite resins, glass ionomer cements, and resin-modified glass ionomer cement within standardized and homogeneous laboratory conditions. Methods: This study evaluated the flexural strength of seven restorative materials: four composites (Filtek™ Z250, Filtek™ Supreme XT, Gradia, Premise), two GICs (Ketac™ Molar Easymix, GC Fuji IX GP), and one RMGIC (Vitremer). Standardized specimens were prepared and tested using a three-point bending protocol with a universal testing machine (Zwick-Roell Z005). A total of 49 specimens were fabricated and analyzed. Statistical analysis was performed with a one-way ANOVA followed by Tukey’s post hoc test. Results: The flexural strength value of composite resins was significantly greater than that of the glass ionomer and resin-modified glass ionomer cements (p < 0.001). Filtek™ Z250 had the highest flexural strength, and Vitremer, a resin-modified glass ionomer cement, exhibited intermediate performance. Ketac™ Molar Easymix had the lowest values among conventional glass ionomer cements, whilst the flexural strength values obtained for GC Fuji IX GP were similar to some composite materials but with higher variability. Conclusions: Composite resins remain the most durable option for pediatric restorations in stress-bearing areas, whereas RMGICs provide a compromise between mechanical performance and biological advantages such as fluoride release and biocompatibility. Conventional GICs, despite their lower flexural strength, retain clinical relevance in low-load sites and for patients at a high risk of caries. Material selection in pediatric dentistry should therefore be tailored to the child’s age, tooth location, and functional demands to ensure long-lasting, minimally invasive restorations. This study involved only mechanical properties alone, and biological aspects, such as fluoride release and biocompatibility, were not considered. Material selection in pediatric dentistry should therefore take into account mechanical requirements, restorative location, and clinical environment.

Fluoride-releasing adhesives in orthodontics help protect enamel. The study compared the fluoride release, recharge, and re-release properties of three light-cure orthodontic bonding adhesives: Group A: Transbond TM Plus Color Change, Group B: Waldent Orthobond LC, and Group C: Koden EZ Bond. The study conducted an in-vitro investigation using 24 maxillary first premolar teeth bonded with one of three fluoride-releasing adhesives after etching. Each sample was placed in artificial saliva, and fluoride release was measured over 60 days using a fluoride electrode. After initial release measurement, specimens were soaked in 1000 ppm fluoride solution for 5 minutes, rinsed, and placed in new containers with distilled water before re-release measurements. Statistical Analysis: One-way ANOVA and Repeated Measures ANOVA tests were used to determine significance, with the Bonferroni posthoc test for further analysis. The fluoride release rate decreased gradually over time for all three groups. The highest fluoride release occurred on Day 1 for all three bonding agents, with a significantly reduced fluoride release by Day 2. Group A exhibited consistent and highest overall fluoride release throughout the 60 days. Group B gradually declined to release fluoride until Day 7, releasing the least fluoride throughout the study. Group C had a higher fluoride release on Day 1 and Day 2 but slowly declined until Day 14. Group B and Group C sharply declined fluoride release by Day 30 and almost negligible amounts on Day 60. All three agents noted enhanced fluoride release post-recharge, with continuous release until day 14. Greater release on days 7 and 14 compared to the initial release in all three groups. Transbond Plus Color Change: Consistent high fluoride was released initially and post-recharge. Waldent Orthobond LC: Lower release throughout the study. Koden EZ Bond: High initial release and post-recharge but continuing to decrease until Day 14.

This in vitro study evaluated the flexural strength, fluoride release, water sorption, and solubility of a high-viscosity hybrid glass ionomer cement (HVGIC, Equia Forte HT, GC Europe) over 28 days following six surface treatments: Equia Forte Coat (light-cured, 20s), bonding agent (Clearfil SE Universal Bond, 20s), light-curing alone as thermal treatment (20s or 60s), petroleum jelly, and untreated control. Specimens were stored in artificial saliva at 37 °C. Flexural strength (three-point bend test, ISO 4049:2019) and fluoride release were assessed at 24, 48, 96 h and 28 days. Sorption and solubility were measured at 28 days. Statistical analysis included bivariate tests, Kaplan-Meier survival curves, Tukey’s post-hoc, and Weibull regression.Proprietary coat and bonding agent reached the minimum required strength (MRS = 80 MPa) fastest (< 2 days), followed by petroleum jelly (2.5 days), 60s light curing (3 days), 20s (4 days), and control (5.5 days). Control showed the highest fluoride release initially, while at 28 days, 60s light-curing released the most fluoride. Proprietary coat and bonding agent showed minimal release. No significant differences in water sorption or solubility were found.These findings suggest that specific coatings or prolonged light curing can improve HVGIC performance and longevity of restorations.

BackgroundConventional Glass Ionomer Cement (GIC) is widely used in restorative dentistry due to its biocompatibility and fluoride release; however, its limited mechanical strength and bioactivity restrict its broader clinical applications. Reducing glass powder particle size represents a promising approach to enhancing its physicochemical performance.ObjectiveTo investigate the effect of glass powder particle size reduction on the physicochemical and mechanical properties of a conventional GIC.MethodsFour groups of conventional GIC were prepared by modifying glass powder particle size through one- or two-step ball milling. Particle size distribution (PSD) and field emission scanning electron microscopy (FE-SEM) were used to verify particle morphology, while energy dispersive x-ray spectroscopy (EDX), x-ray diffraction (XRD), and Fourier-transform infrared spectroscopy (FTIR) confirmed chemical composition. The groups included: A – submicron (average 576.9 nm), B – nano (average 92.4 nm), C – hybrid (average 352.6 nm; composed of both nano and submicron particles), and D – control (936.8 nm, unmodified). Evaluations included pH, fluoride, and calcium ion release (over 28 days), initial setting time, compressive strength, and diametral tensile strength. Data were analyzed using one-way analysis of variance (ANOVA) with Tukey's honestly significant difference (HSD) test (p < 0.05).ResultsGroup B (nano) exhibited the highest fluoride (8.4 ± 0.2 ppm at 3 h) and calcium ion release (1.3 ± 0.08 ppm at 3 h), and the most alkaline pH (6.6 ± 0.09 at day 28). Particle size reduction significantly increased ion release and pH over time but reduced compressive strength (99.02 ± 4.01 MPa) and prolonged setting time (426 ± 10.14 s). The hybrid group (Group C) demonstrated a balanced profile between ion release and mechanical strength, with no chemical alteration observed across groups.ConclusionReducing GIC particle size to the nanoscale enhances ion release and alkalinity but compromises mechanical strength. A hybrid formulation incorporating both nano- and submicron-sized particles provides an optimal balance between bioactivity and strength, offering a promising direction for future development of GICs.

To evaluate the laboratory potential secondary caries reduction of restorative dental materials. 20 maxillary molars received Class V cavities on both buccal and lingual surfaces with enamel and root surface margins adjacent to the restorations. The teeth were randomly assigned into four groups with five teeth per group. The treatment groups were: (1) Filtek Bulk Fil (negative control); (2) Equia Forte glass-ionomer (positive control); (3) Beautifil giomer (fluoride releasing); and (4) Activa Restorative (fluoride releasing). All teeth were restored following the manufacturers' instructions. All teeth received 10,000 thermal cycles followed by immersion in a demineralizing solution to produce artificial caries-like lesions. Polarized light microscope evaluation was performed on longitudinal sections (30 enamel lesions per the ten Cate method, and 30 root surface lesions per group). Lesion depth and wall lesions for both enamel and root surface adjacent to the restorations were evaluated using ANOVA and Duncan's Multiple Range test (P< 0.05). On enamel surfaces, a significantly increased difference was seen with Filtek Bulk Fil compared with the other restorative materials for primary surface lesion depths and wall lesion frequency (P< 0.05: ANOVA and Duncan's Multiple Range Test). Significant difference was found with Activa Restorative (significantly less) compared with Equia Forte glass ionomer and Beautifil Giomer for primary surface lesion depths and wall lesion frequency (P< 0.05: ANOVA and Duncan's Multiple Range Test). On root surfaces, a significantly increased difference was recorded with Filtek Bulk Fil compared with the other restorative materials for primary surface lesion depths and wall lesion frequency (P< 0.05: ANOVA and Duncan's Multiple Range Test). A significant difference was found with Activa Restorative (significantly less) compared with Equia Forte glass ionomer and Beautifil giomer for primary surface lesion depths and wall lesion frequency (P< 0.05: ANOVA and Duncan's Multiple Range Test). Both lesion depth and frequency of wall lesions in the enamel and root surfaces adjacent to the restorations in all treatment groups were significantly (P< 0.05) reduced compared with the control group for a enamel and root cavosurface wall lesions, which may imply effect of fluoride release from fluoride-containing restorative materials vs non-fluoride containing ones. Activa Restorative, compared to Equia Forte glass ionomer and Beautifil giomer, showed statistically significantly less enamel and root surface wall lesions.

Optimization of 3-butenoic acid-modified polyalkenoic acid for enhanced glass ionomer cement performance.

A scoping review of hydroxyapatite-modified glass ionomer cements used for restorative dentistry.

Functional glass ionomer cement modified with phosphate and zinc oxide nanoparticles: in vitro insights into physicomechanical behavior, cytotoxicity and antimicrobial activity.

Filamentous cyanobacterium Spirulina platensis mediates phosphate biomineralization for efficient fluoride immobilization and drives metabolic shift toward stress resistance and biomineralization.

ABSTRACT Time‐resolved fluoride release from alkali‐fluoride nanoparticles in water is quantified to decouple lattice‐intrinsic from surface‐mediated effects on dissolution. Bare and coated and particles are examined under fixed matrix conditions using a dialysis‐coupled fluoride ion‐selective electrode (‐ISE). Dissolution kinetics are fitted with a speciation‐aware model to extract activity‐based solubility constant and an effective rate constant ; TEM, DLS, and ICP‐OES provide morphological and mass‐related confirmation. dissolves faster and reaches higher fluoride plateaus than , despite the lower bulk solubility product of LiF, consistent with facet/morphology‐controlled reactivity. Fits yield a quartz‐like dependence on undersaturation for but indicate inhibition/passivation near equilibrium for . Surface chemistry primarily suppresses rates: mesoporous silica reduces by about an order of magnitude with little change in plateau concentration; poly(acrylic acid) decreases for both lattices and lowers the plateau for ; an amphiphilic polymer causes moderate suppression and shows localized notch etching at coating vacancies. Joint reporting of matrix‐specific apparent and activity‐based solubility enables cross‐comparison. The resulting lattice‐surface map provides design guidance for engineering lanthanide‐doped nanoparticles with predictable aqueous stability for imaging, sensing, and theranostic applications.

This study systematically investigated the driving mechanisms and feedback effects of fluoride pollution gradients on fungal communities in water-soil systems, using the Qingshui River basin in Ningxia, China, as a case study. In 2022, 66 sets of samples, each comprising water, sediment, and riparian soil, were collected across three phases (May, July, December). High-throughput sequencing combined with fluoride speciation analysis revealed that fluoride pollution significantly reduced fungal alpha diversity (low-fluoride group > high-fluoride group I > high-fluoride group II), with aquatic habitats exhibiting the most sensitive response. Ascomycota and Chytridiomycota were identified as dominant fluoride-tolerant phyla, and Ascobolus and Cladosporium as representative tolerant genera. Fungi influenced fluoride speciation through mediating mineral weathering and organic matter metabolism; for instance, Humicola promoted fluoride immobilization, while Archaeorhizomyces participated in organic matter-bound fluoride (O.M.-F) metabolism. Fungi in sediments tended to promote the accumulation of residual fixed fluoride (Res-F), whereas those in riparian soils exhibited dual regulatory effects on the release of bioavailable fluoride (Ba-F). This research elucidates the succession patterns of fungal communities under fluoride pollution and their feedback mechanisms on fluoride biogeochemical cycling, offering a theoretical basis for ecological restoration in high-fluoride regions.