Search Results (263)

Amorphous calcium phosphate (ACP) is a well-established bioceramic material known to promote the remineralization of dental hard tissues. White spot lesions (WSLs) represent the initial stage of enamel demineralization and are frequently observed in patients with fixed orthodontic appliances or inadequate oral hygiene. Although recommendations for remineralizing agents include both the prevention of lesion progression and the stimulation of tissue remineralization, the clinical efficacy of ACP-based materials remains under debate. This systematic review, registered in the PROSPERO database (CRD42024540595), aims to evaluate the clinical efficacy of casein phosphopeptide-amorphous calcium phosphate (CPP-ACP)-based products in the remineralization of WSLs and to compare these outcomes with those achieved using non-bioceramic approaches. Inclusion criteria comprised randomized clinical trials, prospective cohort studies, and pilot studies conducted on human subjects with WSLs affecting permanent teeth. Studies involving artificial WSLs or non-cariogenic enamel lesions were excluded. The quality of the included studies was assessed using the Cochrane Risk of Bias 2 (RoB 2) tool. Fourteen articles met the inclusion criteria and were analyzed. The main findings indicate that CPP-ACP is clinically effective in promoting the remineralization of WSLs, although the results were inconsistent across studies. Comparisons with placebo and resin infiltration treatments revealed greater efficacy for CPP-ACP. The combination of CPP-ACP with fluoride appeared to further enhance the remineralizing effect on WSLs. Additional standardized clinical studies with longer follow-up periods are warranted to confirm these outcomes. Full article

Improper emissions from industrial activities pose toxicological risks to groundwater safety. Based on an environmental forensic identification case involving livestock (sheep) damage caused by groundwater pollution in a pastoral area, we comprehensively evaluated groundwater quality risks, toxicological risks, and pollution sources using multivariate statistical methods, the Nemerow index method, and a non-carcinogenic health risk model. The potential specific pollutants in the region mainly included calcium, potassium, sodium, magnesium, manganese, fluoride, chloride, sulfate, ammonia nitrogen, total dissolved solids, and nitrate. An evaluation of the groundwater health risk factors showed that fluoride, nitrate, and manganese pose higher health risks (HQ > 1), as fluoride > nitrate > manganese. This suggests that these three pollutants were the primary causes of livestock damage. Identification of pollution sources using multivariate statistical analysis revealed that the main pollutants in the groundwater originate from two rare earth enterprises in the surrounding industrial park, followed by the emissions from animal husbandry. This study provides guidelines into comprehensive regional toxicological risk assessment and source tracing, offering an identification method for similar forensic environmental damage cases. Full article

This study aimed to evaluate the fluoride content and other key physicochemical properties in commercially available black tea infusions, with a focus on tea form and geographic origin, in order to assess their contribution to total dietary fluoride intake. Methods: A total of 121 black tea samples were analyzed, including 66 loose-leaf, 42 bags, and 13 pyramid-bag teas. Infusions were prepared using standardized brewing protocols. Fluoride concentrations were determined with an ion-selective electrode, while the pH, buffer capacity, titratable acidity, calcium, and inorganic phosphorus were also measured. Statistical analysis included ANOVA, Tukey post hoc tests, and Pearson correlation analysis. Results: Fluoride content varied significantly by tea form and origin. Infusion of tea bags exhibited the highest fluoride, calcium, and acidity levels, while loose-leaf teas had the lowest. Teas from Africa contained approximately twice as much fluoride as those from Central or East Asia. Significant correlations between fluoride, calcium, and phosphorus were observed, particularly in tea-bag infusions, suggesting processing influences mineral release. Conclusions: Black tea, particularly in bag form and sourced from African regions, may significantly contribute to daily fluoride intake. Given the potential to exceed recommended fluoride thresholds, especially in individuals consuming multiple cups daily or living in fluoridated areas, these findings underscore the importance of consumer awareness and possible product labeling to guide safe consumption. Full article

This study focuses on developing a novel clinker-free cement, specifically comprising phosphorus slag-based cementitious materials (PSCMs), by utilizing lime and industrial byproducts, including granulated electric furnace phosphorus slag and fluidized bed combustion bottom ash. The optimal composition of PSCM was determined by investigating the effects of different proportions of activators (water glass and sodium sulfate) and retarder (potassium fluoride) on the setting time and the mechanical strength of PSCMs. Performance evaluations demonstrated that the compressive and flexural strengths of the optimal PSCM formulation at 28 days were 64.1 MPa and 7.5 MPa, respectively. Notably, concrete prepared with the optimal PSCM exhibited superior freeze–thaw resistance and sulfate resistance compared to Portland cement concrete of equivalent strength grades. The comprehensive characterization of selected PSCM compositions, conducted using X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), and scanning electron microscope–energy-dispersive spectrometry (SEM-EDS), provided in-depth insights into the interrelationship among mechanical properties, durability, and microstructural characteristics. SEM-EDS analysis confirmed that calcium aluminosilicate hydrate and sodium aluminosilicate hydrate are the predominant hydration products of PSCMs. FTIR and TG analyses elucidated the continuous hydration behavior of PSCMs during the curing process, while SEM observations revealed a densely compact microstructure in the hardened PSCM paste. Full article

This study evaluated the pH, fluoride (F), and calcium (Ca) concentrations in saliva-derived microcosm biofilms following treatments with dentifrices applied at different amounts and F concentration. Human saliva was inoculated into McBain culture medium, and treatments were applied at 72/78/96 h (1 min). Fluoridated dentifrices containing 550 or 1100 ppm F (550F and 1100F, respectively) were used at the following combinations (intensities): (i-1) 550F/0.08 g or 1100F/0.04 g; (i-2) 550F/0.16 g or 1100F/0.08 g; (i-3) 550F/0.32 g or 1100F/0.16 g. A negative control (fluoride-free dentifrice—PLA) was also included. Biofilm F and Ca were measured with an ion-selective electrode and colorimetrically, respectively, while pH in the culture medium was measured with a pH electrode. Data were subjected to ANOVA and Student–Newman–Keuls’ test (p < 0.05). F-dentifrices did not significantly alter pH compared to PLA, except for 1100F at i-3. Biofilm F levels at i-1 and i-2 were comparable, for both 550F and 1100F, while 1100F at i-3 led to the highest biofilm F concentration. All F-groups showed significantly higher Ca levels than PLA, especially at i-2 and i-3. In conclusion, the interplay between dentifrice amount and F concentration was more influential on the biofilm’s inorganic composition and pH than either variable alone. Full article

Background: Due to limitations of fluoride (F) treatment as a main caries preventive measure, it is important to consider the use of other dental caries preventive measures to reduce caries prevalence, especially in its early stages. Recently, new remineralizing agents appeared on the market, with their commercial availability in a variety of oral care products. Objectives: The purposes include providing a scoping review that represents caries remineralizing efficacies of only commercially available products and their existing adverse effects (if it is presented) and ensuring that only evidence-based approved products are included. Methods: The following databases were used in searching scientific literature on 28 October 2024: PubMed, PubMed Advanced Search, MeSH database, and PubMed Clinical Queries. The study selection criteria were as follows: for laboratory, in vitro, and/or in situ—remineralization of enamel-scanning electron microscopy, spectroscopy, microhardness test, light microscopy, profilometry, transverse microhardness microradiography, integrated mineral loss, light microscopy, photothermal radiometry; if it was a randomized controlled trial—CONSORT protocol, ICDAS system (to detect dental caries), diagnostic additional devices; antibacterial ability-colony forming units, DNA-based sequencing, scanning electron microscopy, crystal violet staining, and confocal laser scanning microscopy. Results: This review includes 98 papers: 14 of them describing the current status of caries patterns in the world, 60 studies (45 laboratory studies and 15 RCTs), and 24 systematic reviews were analyzed in order to detect whether new remineralizing agents can replace fluoride in further caries prevention. Conclusions: All reviewed new remineralization agents could be used without additives to treat early caries lesions, but the combination with F promotes better remineralization. Only HAP demonstrated its potential to serve as an alternative to fluoride in oral care products. However, further clinical studies are needed to prove its role in the remineralizing process of initial caries lesions. One also needs to ensure that both the clinical trials and in vitro lab studies use the best gold standards to validate any changes in the tooth structure, both remineralization and demineralization. Full article

Fluoride gels are widely used in dental prophylaxis due to their proven ability to prevent demineralization and promote remineralization of hard dental tissues. However, the effectiveness of fluoride release from such gels may be significantly influenced by environmental factors such as pH and the presence of calcium ions. This in vitro study aimed to evaluate how these variables affect fluoride ion release from three commercially available fluoride gels—Clarben, Flairesse, and Lunos. The gels were incubated in artificial saliva of varying pH levels (4.5, 6.0, 7.0, and 7.5) with and without the addition of calcium, as well as in other water-based media—tap water, deionized water, and 0.9% NaCl solution. Fluoride release and changes in pH were measured and statistically analyzed using a multifactorial ANOVA. The results revealed that fluoride release was highest in calcium-free environments and at neutral to slightly alkaline pH, while the presence of calcium significantly reduced fluoride availability. Among the tested products, Flairesse and Lunos exhibited sensitivity to calcium’s presence, unlike Clarben. Fluoride release was generally higher in water than in artificial saliva. Additionally, all gels induced a decrease in pH, which varied depending on the initial pH and calcium content. These findings underline the importance of environmental conditions in optimizing the clinical efficacy of fluoride gel applications. Full article

Calcium fluoride (CaF₂) crystals are widely utilized in deep-ultraviolet (DUV) lithography due to their excellent optical properties. The laser-induced degradation and damage of CaF₂ crystals is a critical concern that restricts its extended application. Impurities of CaF₂ crystal are considered a key factor affecting its laser resistance. Establishing the quantitative relationship and mechanism of impurity content impacting the degradation and damage characteristics of CaF₂ crystal is essential. This study investigated the characteristics of different impurity contents affecting the degradation and laser-induced damage thresholds (LIDTs) of CaF₂ crystals under X-ray and 193 nm pulsed laser irradiations, and quantitatively analyzed the degradation process and mechanism. Our findings demonstrate that impurities at ppm levels significantly diminish the transmittance of CaF₂ crystals across various wavelengths following X-ray irradiation. In contrast, these impurities have a negligible effect on the LIDT test results, suggesting distinct damage mechanisms between X-ray and laser irradiation. This study provides valuable insights for optimizing the CaF₂ crystal fabrication process and enhancing irradiation resistance. Full article

Objectives: This study aimed to compare in vitro the protective effect of two enamel remineralizing agents, a varnish containing β-tricalcium phosphate with sodium fluoride (β-TCP-F) and a paste containing casein phosphopeptide-amorphous calcium phosphate with sodium fluoride (CPP-ACP-F), on artificially demineralized human enamel. Methods: A total of 120 human third molar enamel specimens were randomly assigned to four groups (n = 30 each): Group I (healthy enamel, control), Group II (initially demineralized, lesioned enamel), Group III (demineralized enamel and treated with β-TCP-F), and Group IV (demineralized enamel and treated with CPP-ACP-F). Groups II–IV underwent, for 15 days, a daily pH cycling regimen consisting of 21 h of demineralization under pH 4.4, followed by 3 h of remineralization under pH 7. Groups III and IV were treated with either β-TCP-F or CPP-ACP-F, prior to each 24 h demineralization–remineralization cycle. Fluoride ion release was measured after each pH cycle. Surface hardness, roughness, wettability, and Streptococcus mutans biofilm formation were assessed on days 5, 10, and 15 after a daily pH cycle. Results: CPP-ACP-F treatment showed a larger improvement in surface hardness (515.2 ± 10.7) compared to β-TCP-F (473.6 ± 12.8). Surface roughness decreased for both treatments compared to initially lesioned enamel; however, the decrease in roughness in the β-TCP-F group only reached a value of 1.193 μm after 15 days of treatment, a significantly larger value in comparison to healthy enamel. On the other hand, the decrease in roughness in the CPP-ACP-F treatment group reached a value of 0.76 μm, similar to that of healthy enamel. Contact angle measurements indicated that wettability increased in both treatment groups (β-TCP-F: 71.01°, CPP-ACP-F: 65.24°) compared to initially lesioned samples in Group II, reaching WCA values similar to or smaller than those of healthy enamel surfaces. Conclusions: Both treatments, β-TCP-F and CPP-ACP-F, demonstrated protective effects against enamel demineralization, with CPP-ACP-F showing superior enhancement of surface hardness and smoother enamel texture under in vitro pH cycling conditions. β-TCP-F varnish and CPP-ACP-F paste treatments counteracted surface modifications produced on human healthy enamel by in vitro demineralization. Full article

Extreme precipitation events are one of the common hazards in eastern Texas, generating a large amount of storm water. Water running off urban areas may carry non-point source (NPS) pollution to natural resources such as rivers and lakes. Urbanization exacerbates this issue by increasing impervious surfaces that prevent natural infiltration. This study evaluated the efficacy of rain gardens, a nature-based best management practice (BMP), in mitigating NPS pollution from urban stormwater runoff. Stormwater samples were collected at inflow and outflow points of three rain gardens and analyzed for various water quality parameters, including pH, electrical conductivity, fluoride, chloride, nitrate, nitrite, phosphate, sulfate, salts, carbonates, bicarbonates, sodium, potassium, aluminum, boron, calcium, mercury, arsenic, copper iron lead magnesium, manganese and zinc. Removal efficiencies for nitrate, phosphate, and zinc exceeded 70%, while heavy metals such as lead achieved reductions up to 80%. However, certain parameters, such as calcium, magnesium and conductivity, showed increased outflow concentrations, attributed to substrate leaching. These increases resulted in a higher outflow pH. Overall, the pollutants were removed with an efficiency exceeding 50%. These findings demonstrate that rain gardens are an effective and sustainable solution for managing urban stormwater runoff and mitigating NPS pollution in eastern Texas, particularly in regions vulnerable to extreme precipitation events. Full article

This study achieved the preparation of budget-friendly stratified Ca-Al adsorbents using a simplified precipitation synthesis route with subsequent pyroprocessing, showing superior defluoridation capabilities in aqueous environments. The structural properties and defluoridation performance of the adsorbents were systematically investigated by optimizing critical synthesis parameters, including calcium-to-aluminum molar ratios, the solution pH during co-precipitation, and calcination temperature. Characterization results revealed that the optimal sample (prepared at a Ca/Al ratio of 2:3, initial pH of 10, and calcination temperature of 600 °C) exhibited a high specific surface area, ordered mesoporous structure, and abundant surface hydroxyl groups, facilitating efficient fluoride adsorption. Batch adsorption experiments demonstrated significant effects of adsorbent mass, solution pH, and initial fluoride concentration on removal efficiency. The isothermal adsorption characteristics conformed to the Langmuir model, complemented by pseudo-second-order kinetic compliance, which jointly confirmed chemisorption-dominated monolayer coverage. Notably, the maximum adsorption capacity reached 263.33 mg g⁻¹, surpassing most comparable adsorbents reported in the literature. The material maintained a superior fluoride removal performance across a wide pH range (4~12) and exhibited superior recyclability. Rapid adsorption kinetics were observed, with equilibrium achieved within 60 min. The material showed a good removal effect in actual fluoride-containing smelting wastewater, which further proved its application potential. In addition, the analysis of the adsorption mechanism showed that the removal of fluoride was mainly achieved through the coordination between fluoride and metal ions and the ion-exchange reaction with surface hydroxyl groups. These findings suggest that the adsorbent has significant prospects for practical water quality fluoride removal applications. Full article

Background: Dental fluorosis (DF) is an irreversible alteration of tooth enamel formation caused by excessive fluoride (F) consumption during tooth growth, leading to skeletal fluorosis development due to the high F content of tap water, which should be detected. Objective: To detect the signs of skeletal fluorosis by comparison of the bone mineral density (BMD) of the lumbar spine, femoral neck, and total femur, and the fluor (F) intake from water between adults without and with DF from northwestern Mexico. Methods: Participants were 36 adults without DF (G1) and 42 with DF (G2). Dean criteria, DEXA, and SPADNS methods were used to evaluate DF, BMD, and F content in water, respectively. Results. G1 participants consumed 0.789 ± 1.55 mg F/d from water with 0.385 ± 0.32 mg F/L, while G2 participants drank 2.42 ± 2.65 mg F/d from water with 1.46 ± 0.59 mg F/L. The binary variable DF and BMD values were not associated (p > 0.05); however, according to severity degree, questionable DF was associated with total femur BMD (p = 0.025). BMD in the evaluated regions was no different between both groups and could be related to actual moderate levels of F in the tap water and to the partial or total consumption of bottled water. Conclusions. There was no association between DF and the measured BMD to infer skeletal fluorosis. Bone region BMD was no different between both evaluated groups and could be related to adequate F intake, with moderate F levels in tap water, and the consumption of negligible F content bottled water. Full article

In order to effectively recover Li from cathode active materials of lithium-ion batteries, model samples of LiCoO₂ mixed with polyvinylidene fluoride (PVDF) were calcined at temperatures of 350–700 °C under an Ar or air atmosphere. Complete Li recovery was achieved by calcining the model sample at 400 °C under an Ar atmosphere, followed by water leaching. Additionally, to immobilize PVDF-derived F, an impurity in Li purification, we explored the use of calcium compounds (Ca(OH)₂ and CaCO₃) and a layered double hydroxide in both dry and wet processing methods. In the wet process, F was fixed by adding Ca(OH)₂ to an aqueous LiF solution containing 1000 ppm of F. We confirmed that 98.6% of F was successfully removed from the solution after repeated fixation procedures. Furthermore, the unreacted Ca in the solution was separated and removed as CaCO₃ by concentrating the solution. Full article

The aim of this study was to assess the mechanical properties of experimental flow composites incorporating remineralizing and bactericidal fillers (hydroxyapatite (HAp), calcium fluoride, and nanosilver). The evaluated properties included wear resistance, dynamic properties (impact strength), hardness, and static strength (compressive and bending strength). This work includes SEM analysis. The specimens were prepared using a commercial light-cured composite material based on bisphenol A-glycidyl dimethacrylate (Bis-GMA) (Arkona Flow Art, Niemce, Poland) and composite material modified by adding 2 wt%, 5 wt% of hydroxyapatite powder containing fluoride (calcium fluoride), and nanosilver. For this purpose, hydroxyapatite (HAp) with a grain size of 30 μm, which was previously synthesized using the wet method, was used. The results were evaluated against the ISO 4049 standard. The results were subjected to statistical analysis using IBM SPSS Statistics, version 29 (IBM Corp., Armonk, NY, USA). A significance level of 5% (α = 0.05) was established. Based on the hardness measurements obtained in this study, it can be concluded that the incorporation of hydroxyapatite, calcium fluoride, and nanosilver fillers increased the hardness of the flowable composites (89 ShD). The results revealed that incorporating fillers such as hydroxyapatite, nanosilver, and calcium fluoride led to a decrease in the impact strength of the material (0.095 J/cm²). The results of the compressive strength tests revealed that the flowable composite containing 2 wt% of HAp, F, and Ag exhibited the highest compressive strength (190 MPa) among all of the tested materials. Among the experimental composites, the highest bending strength was observed in the variant containing 2 wt% of HAp, F, and Ag, with a value of 76.48 MPa. Significantly higher wear was observed for the composite containing nanosilver filler (4.02 × 10⁻⁴ Mm³/Nm) compared to the other composites. However, the inclusion of nanosilver as a filler in the composite matrix was found to significantly deteriorate the mechanical properties of the material. Full article

This systematic review aims to evaluate factors influencing fluoride release from dental nanocomposite materials. A comprehensive database search was conducted in February 2025 using PubMed, Web of Science, and Scopus. The search terms “fluoride release AND nanocomposites” were applied following PRISMA guidelines. Out of 336 initially identified articles, 17 studies met the inclusion criteria and were selected for analysis. Seventeen studies confirmed that fluoride-releasing nanocomposites are effective, with fluoride ion release influenced by material composition, nanofiller type, and storage conditions. Studies showed that acidic environments (pH 4–5.5) significantly enhanced fluoride release, particularly in materials containing nano-CaF₂ or fluoridated hydroxyapatite, which responded to pH changes. Quantitative comparisons revealed that daily fluoride release values ranged from <0.1 μg/cm²/day in commercial composites to greater than 6500 μg/cm²/day in BT-based nanocomposites and up to 416,667 μg/cm²/day in modified GICs. Additionally, some composites exhibited fluoride recharging capabilities, with materials incorporating pyromellitic glycerol dimethacrylate (PMGDM) and ethoxylated bisphenol A dimethacrylate (EBPADMA) demonstrating prolonged fluoride and calcium ion release after recharge exposure, rather than the highest initial values. Despite releasing lower fluoride levels than conventional GIC and RMGI materials, fluoride-releasing nanocomposites demonstrate significant anti-caries potential and clinical applicability, with some formulations supporting periodontal regeneration and caries prevention around orthodontic brackets. However, the lack of consistency in study protocols—including differences in storage media, sample geometry, and measurement methods—limits direct comparison of outcomes. Therefore, the most critical direction for future research is the development of standardized testing protocols to ensure reliable, comparable results across material groups. Full article