Search Results (35)

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

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

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

Reusing treated effluent from municipal wastewater treatment plants is essential for addressing freshwater scarcity, a key objective of the United Nations Sustainable Development Goals (SDGs). While closed-circuit reverse osmosis (CCRO) has shown promise in municipal reuse facilities, the comprehensive assessment of water quality parameters, especially at higher recovery rates, is lacking. In this study, at the San Jacinto Valley Regional Water Reclamation Facility (SJVRWRF), we evaluated the performance of CCRO in treating municipal wastewater tertiary effluent, focusing on high recovery rates. Our analysis of selected chemical parameters across recovery rates ranging from 90% to 95% revealed the effective removal of suspended particles by CCRO. However, variations in removal rates were observed among ions, with chloride removal at 96.3% and nitrate removal at 79.6%, contrasting with fluoride’s complete removal and sulfate’s 99.7% removal rate. Divalent ions like calcium and magnesium exhibited better rejection than monovalent ions such as sodium and potassium. Additionally, the removal efficiency of total dissolved solids (TDSs), alkalinity, chloride, nitrate, sodium, and potassium decreased with an increasing recovery rate, while sulfate, calcium, and magnesium removal rates remained stable. These findings enhance our understanding of membrane treatment processes, providing valuable insights for future water reclamation projects to combat freshwater resource scarcity. Full article

Phosphogypsum (PG), a by-product of phosphoric acid production, contains high levels of fluorine and phosphorus impurities, which negatively impact the strength and setting time of PG-based cement materials and pose environmental risks. This study explores a dual approach combining physical adsorption using zeolite powder and chemical modification with quicklime (CaO) to immobilize these impurities. The composition of 90 wt.% PG, 5 wt.% zeolite powder, and 5 wt.% quicklime reduces the soluble phosphorus to below the detection limits and significantly lowers the free water content in the PG. Through SEM, XRD, and FT-IR analyses, it was found that zeolite powder adsorbs fluorine and phosphorus through encapsulation, while quicklime chemically reacts to form insoluble calcium phosphate and calcium fluoride. This transformation decreases the solubility, mitigating potential environmental contamination. The combination of physical adsorption and chemical conversion provides a sustainable strategy to reduce environmental hazards and enhance PG’s suitability for cement-based materials. The findings from this research offer a promising pathway for the sustainable utilization of PG, providing a mechanism for its safe incorporation into building materials, while addressing both environmental and material performance concerns. Full article

Bacterial infections are a common cause of clinical complications associated with the use of orthodontic microimplants. Biofilm formation on their surfaces and subsequent infection of peri-implant tissues can result in either exfoliation or surgical removal of these medical devices. In order to improve the properties of microimplants, hybrid coatings enriched with silver nanoparticles, calcium, and phosphorus were investigated. The present study aimed to assess the microstructure of commercially available microimplants composed of a medical TiAlV (Ti6Al4V) alloy covered with organic–inorganic layers obtained by the sol–gel method using the dip-coating technique. The microstructures and elemental surface compositions of the sterile, etched, and layer-modified microimplants were characterized by scanning electron microscopy with X-ray energy-dispersive spectroscopy (SEM-EDS). Elements such as silver (Ag), calcium (Ca), phosphorus (P), silicon (Si), oxygen (O), and carbon (C) were detected on the microimplant’s surface layer. The SEM observations revealed that control microimplants (unetched) had smooth surfaces with only manufacturing-related embossing, while etching in hydrofluoric acid increased the surface roughness and introduced fluoride onto the microimplants. Layers with only silver nanoparticles reduced the roughness of the implant surface, and no extrusion was observed, while increased roughness and emerging porosity were observed when the layers were enriched with calcium and phosphorus. The highest roughness was observed in the microimplants etched with AgNPs and CaP, while the AgNPs-only layer showed a reduction in the roughness average parameter due to lower porosity. Enhancing the effectiveness of microimplants can be achieved by applying selective surface treatments to different parts. By keeping the outer tissue contact area smooth while making the bone contact area rough to promote stronger integration with bone tissue, the overall performance of the implants can be significantly improved. Full article

The investigation into the implementation and widespread adoption of oyster shell recycling methods aimed at restoring coastal ecosystems and enhancing water quality is currently limited. In this study, we investigated the utilization of oyster shell powder (OSP) as a cost-effective and environmentally sustainable method for treating high-fluoride-concentration wastewater, a byproduct of industrial processes. We conducted extensive laboratory testing to determine the optimal conditions for fluoride removal. This involved variations in OSP doses, particle sizes, and initial wastewater pH levels. The results of these tests showed that OSP achieved fluoride removal efficiencies exceeding 98% at an optimal dosage of 5 g/L. In addition, OSP effectively adjusted the wastewater pH from highly acidic (pH 2) to almost neutral (pH 6.87), demonstrating its effectiveness in real-world industrial wastewater treatment. OSP, derived from oyster shell waste, is rich in calcium carbonate and offers a novel approach to wastewater management by leveraging a natural waste product. This study demonstrates the potential of OSP as a waste management strategy and contributor to the circular economy by repurposing industrial byproducts. Full article

This concise review provides an update on the use of calcium-based materials for the prevention of dental caries. Some calcium-based materials promote remineralization and neutralize bacterial acids, disrupting cariogenic biofilms and inhibiting bacterial growth. Medical Subject Headings of [Dental Caries] and [Calcium] were adopted to search publications. Information related to the aim of this review was extracted and summarized. Common calcium-based materials are calcium phosphate, hydroxyapatite, calcium carbonate, calcium fluoride and casein phosphopeptide–amorphous calcium phosphate (CPP-ACP). Calcium phosphate is commonly used in toothpaste. It provides calcium and phosphate ions, enhances the incorporation of fluoride into caries lesions and increases mineral density. Hydroxyapatite is a form of calcium phosphate that is chemically similar to the mineral found in teeth. It can be applied on teeth to prevent caries. Calcium carbonate can be found in toothpastes. It neutralizes bacterial acids and acts as a calcium reservoir during remineralization. Calcium fluoride is found in dental products and promotes remineralization as a source of fluoride, which can be incorporated into tooth enamel, forming fluorapatite and increasing resistance to caries. CPP-ACP is derived from milk proteins. It contains calcium and phosphate, which help to remineralize tooth enamel. CPP-ACP inhibits cariogenic bacteria. It also interacts with bacterial biofilms and disrupts their formation. These calcium-based materials can be used to boost the preventive effect of fluorides or, alternatively, as a therapy for caries prevention. Full article

(1) Background: This study aimed to establish the effect of calcium lactate enamel pretreatment related to different fluoride types and concentrations on the enamel uptake of alkali-soluble fluorides. (2) Materials: In a blind and randomized in vitro study, a total of 60 teeth are used. The first 30 teeth were cut and randomly allocated into one of the following treatments: (A) calcium lactate pretreatment followed by three different fluoride solutions; (B) the “Fluoride only” group, with slabs treated with three different fluoride solutions; (C) the “Calcium only” group, with slabs treated with calcium lactate solution; (D) slabs treated with deionized water (negative control group). The next 30 teeth underwent all the above described group procedures but were treated with lower fluoride concentrations. Fluoride was extracted from enamel using 1 M KOH solution and analyzed using a fluoride ion-specific electrode. (3) Results: The findings revealed that slabs treated with NaF following calcium lactate pretreatment exhibited significantly greater enamel uptake of alkali-soluble fluoride compared to other substrates. This significant effect was not observed at lower fluoride concentrations. (4) Conclusion: The study demonstrates that pretreatment with calcium lactate followed by treatment with NaF at 226 ppm F significantly enhances the uptake of alkali-soluble fluoride in enamel compared to other fluoride types. Full article

Objectives: The purpose of this study is to evaluate the remineralization potential of primary teeth enamel after being exposed to different laser diode therapies. Methods: Ninety-six vestibular primary teeth enamel samples were divided into eight groups (n = 12) with varying treatments: control (G1), CPP-ACP-fluoride varnish (G2), diode lasers at 980 nm (G3), 808 nm (G4), 450 nm (G5), 980 nm + CPP-ACP-fluoride varnish (G6), 808 nm + CPP-ACP-fluoride varnish (G7), and 450 nm + CPP-ACP-fluoride varnish (G8). Each sample was assessed using a DIAGNOdent^® (KaVo Dental, Biberach, Germany), at baseline, post-treatment, and post-pH cycle remineralization. SEM imaging was performed before and after treatment and following the pH cycle. Results: The results indicated that the 980 nm and 808 nm diode lasers, both alone and in combination with CPP-ACP-fluoride varnish, either maintained or increased the calcium (Ca) weight percentage (Wt%) in the enamel. The 980 nm diode laser combined with CPP-ACP-fluoride varnish (G6) showed a significant increase in Ca Wt%, suggesting a strong remineralization effect. Similarly, the 808 nm diode laser alone (G4) also promoted a substantial increase in Ca Wt%. In contrast, the 450 nm diode laser, whether applied alone or in combination with CPP-ACP-fluoride varnish, resulted in a lower Ca Wt% and an increase in phosphorus (P) Wt%. Most groups, except for the CPP-ACP-fluoride varnish alone (G2), demonstrated an increase in P Wt%, indicating a complex interaction between laser therapy and enamel remineralization. Conclusions: The combined use of laser therapy with CPP-ACP-fluoride varnish significantly enhanced the remineralization of temporary teeth enamel. The 980 nm diode laser + CPP-ACP-fluoride varnish showed the most pronounced improvement in remineralization, while the 808 nm diode laser alone also effectively increased calcium solubility. These findings suggest that higher-wavelength diode lasers, particularly when combined with remineralizing agents, can effectively enhance the mineral content of primary teeth and promote enamel remineralization. Full article

Dentin hypersensitivity (DH) is a common challenge in pediatric patients with molar incisor hypomineralization (MIH), stemming from enamel porosity or exposed dentin after enamel breakdown. This three-arm randomized controlled clinical trial aims to evaluate the effectiveness of three different desensitizing treatment protocols. The study was conducted on 39 children, aged 6–14 years old, with MIH and DH. Group A received casein phosphopeptide plus amorphous calcium phosphate fluoride (CPP-ACPF) mousse and sham light therapy, Group B received placebo mousse and photo-bio-modulation therapy (PMBT), and Group C received both CPP-ACPF mousse and PMBT. DH evaluation using a visual analogue scale was performed at multiple time points. Both CPP-ACPF mousse and PMBT individually demonstrated desensitizing effects on dental elements affected by MIH. While PMBT had a greater immediate effect, the combination of the two therapies proved most effective in reducing DH. The VAS scores were statistically lower in group C compared to groups A and B, both after the first session (p = 0.0001) and after 28 days (p = 0.0005). This study suggests promising avenues for managing DH in MIH patients, highlighting the potential of combined therapies, specifically CPP-ACPF mousse and PMBT, for enhanced clinical outcomes. Full article

This study explored the feasibility of fluoride removal from simulated semiconductor industry wastewater and its recovery as calcium fluoride using fluidized bed crystallization. The continuous reactor showed the best performance (>90% fluoride removal and >95% crystallization efficiency) at a calcium-to-fluoride ratio of 0.6 within the first 40 days of continuous operation. The resulting particle size increased by more than double during this time, along with a 36% increase in the seed bed height, indicating the deposition of CaF₂ onto the silica seed. The SEM-EDX analysis showed the size and shape of the crystals formed, along with the presence of a high amount of Ca-F ions. The purity of the CaF₂ crystals was determined to be 91.1% though ICP-OES analysis. Following the continuous experiment, different process improvement strategies were explored. The addition of an excess amount of calcium resulted in the removal of an additional 6% of the fluoride; however, compared to this single-stage process, a two-stage approach was found to be a better strategy to achieve a low effluent concentration of fluoride. The fluoride removal reached 94% with this two-stage approach under the optimum conditions of 4 + 1 h HRT combinations and a [Ca²⁺]/[F⁻] ratio of 0.55 and 0.7 for the two reactors, respectively. CFD simulation showed the impact of the inlet diameter, bottom-angle shape, and width-to-height ratio of the reactor on the mixing inside the reactor and the possibility of further improvement in the reactor performance by optimizing the FBR configuration. Full article

The Yulong copper deposit in Tibet is a typical porphyry copper deposit, with about 30 million tons of copper oxide ore in the surface layer. However, more than 40% of the copper resources are in a combination state, resulting in an extraction efficiency of only 50% for copper via the hydrometallurgical process. In this study, the process mineralogy of the combined copper oxide ore was systematically investigated and a calcium fluoride-enhanced leaching process is proposed to increase the leaching efficiency of the combined copper ore. The process mineralogy of the combined copper oxide ore was analyzed using various testing techniques, including chemical analysis, X-ray diffraction, and a process mineralogy parameter testing system (Mineral Liberation Analysis). The results revealed that limonite accounted for 86.12% of the sample, and 63.51% of the copper resource existed in the form of combined copper oxide in limonite. However, it is difficult for the uniformly distributed combined copper oxide in limonite to sufficiently make contact with sulfuric acid, which is the leaching agent, resulting in low copper leaching efficiency. The enhanced leaching behavior of the combined copper oxide ores was also investigated, thereby determining effective and economical enhanced leaching conditions. Under optimal conditions, at a grinding fineness ratio of −0.074 mm (accounting for 85%), liquid-solid ratio of 4:1, sulfuric acid concentration of 50 g/L, temperature of 30 °C, CaF₂ dosage of 1% of the ore mass, and leaching time of 4 h, the copper leaching efficiency increased to 60.57%, which was 7.34% higher than that of atmospheric pressure leaching. Finally, the enhanced leaching slag was analyzed using an electron probe microanalyzer. It indicated that fluorine ions can erode the combined copper oxide ore and facilitate the diffusion of hydrogen ions inside the limonite, thereby achieving a strengthening effect. Full article

The aim of this study was to compare the mechanical properties and ion release from a commercially available resin-modified glass ionomer cement to a formulation reinforced by the addition of short glass fibres at various percentages. Methods: Three experimental groups were prepared by adding a mass ratio of 10%, 15% and 20% of short glass fibres to the powder portion of the cement from a capsule (GC Fuji II LC), while the control group contained no fibres. Microhardness (n = 12), fracture toughness, and flexural, compressive and diametral tensile strength (n = 8) were evaluated. To study ion release, readings were obtained utilising fluoro-selective and calcium-selective electrodes after 24 h, 7 days and 30 days (n = 12). The spatial distribution of fibres within the material was evaluated through scanning electron microscopy. The data were analysed using one-way ANOVA with a Bonferroni adjustment. Results: The findings suggest that elevating fibre weight ratios to 20 wt% results in improved mechanical properties (p < 0.05) in microhardness, flexural strength, diametral tensile strength and fracture toughness. In terms of ion release, a statistically significant difference (p < 0.001) was observed between the groups at the conclusion of 24 h and 7 days, when the fluoride release was much higher in the control group. However, after 30 days, no significant distinction among the groups was identified (p > 0.05). Regarding calcium release, no statistically significant differences were observed among the groups at any of the evaluated time points (p > 0.05). SEM showed the fibres were homogeneously incorporated into the cement in all experimental groups. Conclusions: Resin-modified glass ionomer enhanced with short glass fibres at a weight loading of 20% showcased the most favourable mechanical properties while concurrently maintaining the ability to release fluoride and calcium after a 30-day period. Full article