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Dentin tissue can act as a reservoir for bioactive molecules that create signals for cellular proliferation and differentiation to initiate tissue regeneration. Therefore, the aim of this study is to compare the cell viability, inflammatory response, and antimicrobial activity of bovine dentin grain-added calcium-hydroxide (CH-BDG) with different pulp-capping materials.ProRoot MTA, Biodentine, Dycal, TheraCal-LC, and an experimental material, CH-BDG, were examined. Cell viability was determined via the WST-1 assay. The inflammatory response was analysed by the monocyte chemoattractant protein-1 (MCP-1/CCL2) and macrophage inflammatory protein-1α (MIP-1α/CCL3) levels. The antimicrobial activity was evaluated by agar-diffusion.The cell viability of CH-BDG was analogous with Biodentine and control at 24 h. The cell viability of CH-BDG decreased at 48 h, but the rate was higher than ProRoot MTA and Dycal (p<0.05). For MCP-1 and MIP-1α values, there was no significant difference between the control and CH-BDG. The MCP-1 level of CH-BDG was lower compared to other pulp-capping materials (p<0.05). The MIP-1α level of CH-BDG was lower compared to ProRoot MTA, Biodentine, and TheraCal-LC (p<0.05). No inhibition zone was detected against oral microorganisms for CH-BDG.The experimentally developed CH-BDG showed competing properties and additional advantages compared to the existing pulp-capping materials. [ABSTRACT FROM AUTHOR]

With the development of industry and agriculture, eutrophication caused by increasing amounts of phosphorus in the environment has attracted people's attention. On the other hand, copper tailings (CT) is a kind of solid waste with large quantity, large area, and easy to cause groundwater and soil pollution. CT is also a potential resource because of its large specific surface area. CT is intended to be used as an adsorbent for removal phosphate in water, but trace heavy metals and a small amount of phosphate in CT may bring negative effects. Calcium hydroxide (Ca(OH)2) was used to modify CT (CCT), hoping to fix the heavy metals and phosphate in CT at the same time. It was found that the removal capacity of CCT was significantly higher than that of CT. The process of phosphate removal by CCT involves electrostatic sorption and surface precipitation, and there is a synergistic effect between CT and Ca(OH)2. The phosphate removal rate of CCT-0.4 increased with the increase of pH value under alkaline conditions. The XRD patterns of phosphate sorption by CCT mean that Ca3(PO4)2, Ca5(PO4)3(OH) and AlPO4 exist in CCT after phosphate removal, indicating that surface precipitation occurs during the removal process. In summary, the removal mechanism of phosphate by CCT is mainly electrostatic attraction and surface precipitation. [ABSTRACT FROM AUTHOR]

The efficiency of stabilization/solidification (S/S) treated heavy metal contaminated soils may be deteriorated by the changeable external environment. Thus, the toxicity characteristics leaching procedure (TCLP) and pH-dependent leaching test were carried out to evaluate the toxicity of zinc-contaminated soil treated by cement blended with soda residue with consideration of freezing–thawing (F-T) cycles. Results showed that F-T cycles had little impact on the toxicity of Zn-contaminated soils treated with cement-soda residue, and the leached Zn2+ concentration didn't exceed the regulatory limit defined by the standards. Dissolution/precipitation of zinc hydroxides was suggested to be the controlling mechanism for Zn2+ leachability. Besides, Zn2+ immobilized by chemical incorporation and encapsulation by calcium silicate hydrates (CSHs) and calcium aluminate hydrates (CAHs) still remained stable in an acidic condition. Results of X-ray diffraction (XRD) and scanning electron microscopy (SEM) verified that F-T cycles impose little impact on the chemical properties of the specimens, but only alter the micro- and macrostructure characteristics. [ABSTRACT FROM AUTHOR]

Aim: Calcium hydroxide (CH) has been considered as a direct pulp capping materials (DPC) for the last decades despite having some limitations. Phosphorylate pullulan (PPL) incorporated with CH (CHPPL) is a novel biomaterial that was introduced as a promising DPC material. Thus, the aim of the study was to evaluate the inflammatory response and mineralized tissue formation (MTF) ability of PPL‐based CH formulations on rat molars after DPC. Methodology: This study consisted of six groups: CH with 1% PPL (CHPPL‐1); 3% PPL (CHPPL‐3); 5% PPL (CHPPL‐5); Dycal and NEX MTA Cement (N‐MTA) as the positive control, and no capping materials (NC). One hundred twenty maxillary first molar cavities were prepared on Wistar rats. After capping, all the cavities were restored with 4‐META/MMA‐TBB resin and pulpal responses were evaluated at days 1, 7, and 28. Kruskal–Wallis followed by Mann–Whitney U‐test was performed with a significance level of 0.05. Immunohistochemical expression of IL‐6, Nestin, and DMP‐1 was observed. Results: At day 1, CHPPL‐1, N‐MTA, and Dycal exhibited no to mild inflammation, whilst CHPPL‐3, CHPPL‐5, and NC showed mild to moderate inflammation, and the results were significantly different (p <.05). At day 7, mild to moderate inflammation was observed in CHPPL‐1, N‐MTA, and Dycal, whereas CHPPL‐3, CHPPL‐5, and NC exhibited moderate to severe inflammation. Significant differences were observed between CHPPL‐1 and N‐MTA with NC (p <.05), CHPPL‐1 and CHPPL‐3 with CHPPL‐5 and Dycal (p <.05), and CHPPL‐3 with N‐MTA (p <.05). A thin layer of mineralized tissue formation (MTF) was observed in all groups. At day 28, CHPPL‐1, Dycal, and N‐MTA showed no to mild inflammation, whilst CHPPL‐3, CHPPL‐5, and NC exhibited mild to severe inflammation, and statistically significant difference was detected (p <.05). CHPPL‐1, Dycal, and N‐MTA exhibited continuous MTF, whilst CHPPL‐3, CHPPL‐5, and NC had thicker and interrupted MTF. Significant differences were observed between CHPPL‐1, CHPPL‐3, and N‐MTA with NC group (p <.05). Variable expressions of IL‐6, Nestin, and DMP‐1 indicated differences in the materials' impact on odontoblast‐like cell formation and tissue mineralization. Conclusions: These findings suggest that CHPPL‐1 has the potential to minimize pulpal inflammation and promote MTF and had similar efficacy as MTA cement. [ABSTRACT FROM AUTHOR]

The yield of green energy from solid-state anaerobic co-digestion (SSAD) has recently been enhanced by incorporating innovative pretreatment methods and nanoparticles. However, the environmental consequences of employing new processes have not been fully examined. In this study, the environmental impacts of three high-methane-yielding scenarios including SSAD of corn stover blended with dairy manure (DM) denoted as (SYM1), calcium hydroxide-pretreated corn stover (CpCS) blended with DM (SYM2), and the CpCS blended with DM and nanoparticles (SYM3) were assessed and compared the baselines of solid-state and semi-solid-state anaerobic digestion using a life cycle assessment (LCA) approach. The approach investigated the best management practices that would result in high methane yield and low environmental impact. Results of the life cycle assessment indicate the inclusion of calcium hydroxide and nanoparticle has minimal negative environmental impact. There was an environmental gain in GWP when corn stover was co-digestion with DM (SYM1) relative to DM mono-digestions (baselines) and the carbon footprint of SYM1 was less by more than 85% compared to SYM2 and SYM3. However, the large volume of untreated corn stover harnessed for SYM1 scenario resulted in over 75% fossil fuel depletion compared to the other scenarios. The surplus methane from the SYM3 (at least twofold of other scenarios and baselines) in conjunction with being the least with the environmental implication makes the scenario the most attractive option for on-farm practice capable of harnessing the growing organic waste volume. These outcomes can guide trade-off between pretreatment and nanoparticle application to reduce solid-state anaerobic digestion's negative environmental impact. [ABSTRACT FROM AUTHOR]

Objectives: This study aimed to assess the efficacy of different activation techniques in removing calcium hydroxide (Ultracal XS), Ledermix, and Bio-C Temp from simulated internal root resorption (IRR) cavities. Materials and methods: 108 single-rooted maxillary incisors were prepared using Reciproc R50 files. Simulated IRR cavities, 2 mm in diameter and located 8 mm from the apex, were created. Ultracal XS, Ledermix, and Bio-C Temp were applied to the samples, grouped by irrigation activation techniques: Standard Needle Irrigation (SNI), EDDY, Passive Ultrasonic Irrigation (PUI), and XP-endo Finisher (XPF). Medicament removal efficacy was evaluated using a standardized scoring system. Statistical analysis was performed using the Kruskal-Wallis test. Results: XPF and PUI were more effective than SNI in medicament removal across the groups, with no significant difference. EDDY showed no significant difference than other groups. Ledermix was more effectively removed in all activation groups compared to Bio-C Temp. The XPF was superior in removing Ultracal XS compared to Bio-C Temp. However, none of the groups achieved complete medicament removal. Conclusions: XPF and PUI techniques enhance medicament removal efficacy. Bio-C Temp was more difficult to remove from the IRR cavities than other medicaments. Clinical relevance: Bio-C Temp could be removed from the canals less effectively compared to calcium hydroxide and Ledermix. Among the tested irrigation activation methods, XPF and PUI were found to be more effective at removing the tested medicaments. [ABSTRACT FROM AUTHOR]

Electric reduction furnaces cannot be fed fines in the production of manganese ferroalloy as they hinder gas permeability. Thus, agglomeration techniques can be used to minimize the environmental and economic impacts of storing fines. Among these techniques, briquetting is advantageous because it allows for cold agglomeration of the particles and is flexible in terms of particle sizes. Therefore, this work aimed to develop self-reductor briquettes composed of ore manganese fines, dust ferromanganese, charcoal fines, and three different binders. The compaction pressure, curing time, and % binder were optimized to enhance briquette strength through a multivariate experimental design consisting of a screening study using a 23 full factorial design followed by response surface methodology with a spherical central composite design. The results were assessed by analysis of variance, and a regression model was established. The study found that briquettes elaborated with bentonite exhibited an optimized compressive strength of 4.02 MPa, achieved with a compaction pressure of 67.55 MPa and 12.71% bentonite. For briquettes elaborated with pregelatinized starch, a compressive strength of 7.04 MPa was obtained with a compaction pressure of 67.52 MPa, a curing time of 19.51 days, and 8.07% pregelatinized starch. For briquettes agglomerated using slaked lime and molasses, an optimized compaction pressure of 27.09 MPa and a curing time of 23.27 days resulted in a compressive strength of 1.63 MPa. These results suggest that briquettes containing bentonite and pregelatinized starch are feasible substitutes for lump ore in electric furnaces. [ABSTRACT FROM AUTHOR]

Calcium hydroxide was used as a swelling agent and grinding aid to grind together with cellulose raw materials to prepare microfibrillated cellulose (MFC). Carbon dioxide was introduced to obtain MFC coated with calcium carbonate (CMFC). The effect of calcium hydroxide dosage on the fibrillation process of cellulose materials and the characteristics of MFCs and CMFCs were studied. Results show that when the dosage of calcium hydroxide was 5 % (based on cellulose materials), calcium hydroxide could be completely dissolved in water and had a swelling effect on cellulose materials. When the dosage reached 10 %, undissolved calcium hydroxide particles could serve as grinding media to assist in the fibrillation of cellulose materials. When the dosage exceeded 50 %, the auxiliary grinding effect of calcium hydroxide was more obvious. After accelerated carbonation, the generated calcium carbonate nanoparticles were coated on the surface of MFC, which increased its viscosity and decreased water retention value. The presence of calcium carbonate also facilitated the concentration, redispersion, and drying of MFC. The pretreatment, mechanical fibrillation, and accelerated carbonation were carried out in the same equipment without the need for heating or washing. Therefore, this study provides a in situ and one step method for the preparation of MFC. [ABSTRACT FROM AUTHOR]

This study aimed to evaluate the efficacy of different irrigation techniques including standard needle irrigation (SNI), passive ultrasonic irrigation (PUI), EndoActivator (EA), XP‐Endo Finisher (XPF), photon‐induced photoacoustic streaming (PIPS), and shock wave enhanced emission photo‐acoustic streaming (SWEEPS) systems on the penetration of irrigation solutions into dentinal tubules in teeth with calcium hydroxide (CH) applied and oval‐shaped canals by confocal laser scanning microscope (CLSM). Ninety mandibular incisor teeth with oval‐shaped canals were included in this study. After the preparation of teeth using Resiproc Blue R25 (VDW, Munich, Germany) canals were filled with a paste based on CH. The teeth were stored in 100% humidity at a temperature of 37°C for 14 days. According to the irrigation activation systems, the teeth were divided into six groups (n = 15); SNI, PUI, EA, XPF, PIPS, and SWEEPS. In each group, 3 irrigation/activation cycles of 20 s of irrigation and 20 s of activation were performed with the relevant activation method. The root canals were filled with fluorescein sodium (Sigma, Alldrich Co., St. Louis, MO, USA) and activated with the relevant activation method for 30 s. Specimens were sectioned horizontally to 1 ± 0.1 mm at 2, 5, and 8 mm from the apex and then examined under the CLSM. Maximum penetration depth, maximum penetration area and penetration percentage were measured by using Image J software. Data were analyzed using a two‐way analysis of variance (ANOVA) and posthoc Tukey tests (p =.05). No difference was found between the activation systems in terms of maximum penetration depth and maximum penetration area of irrigation solutions in the apical section (p >.05). The penetration percentage of irrigation solutions was higher in PUI and PIPS compared with EA and XPF at the apical section (p <.05). No difference was found between SNI, PUI, PIPS, and SWEEPS in terms of the penetration percentage of irrigation solutions in all sections (p >.05). The penetration percentage of irrigation solutions was higher in the middle and coronal sections compared to the apical section in EA and XPF (p <.05). Tubule penetration of irrigation solutions in SNI was similar between sections. The Tubule penetration area of irrigation solutions in PUI, EA, XPF, PIPS, and SWEEPS was lower in the apical section than in the middle and coronal sections. Research Highlights: The tubule penetration depth and area of the irrigation solutions were similar between the activation systems tested in the apical sections.The Tubule penetration area of irrigation solutions in middle and coronal sections was higher in PUI and PIPS than in SNI. [ABSTRACT FROM AUTHOR]

AbstractAs known, calcium hydroxide Ca(OH)2 is a basic material, that can be used in numerous applications. Recently, many trials have been performed to modify some properties of alkali-activated materials (AAMs) by introducing Ca(OH)2. In general, Ca(OH)2 can be introduced into AAMs in three forms: as a part of a precursor or as an additive, as a sole activator or combined with an auxiliary activator. The incorporation of Ca(OH)2 into different matrices may modify some properties or worsen others. This essentially depends on curing conditions, the ratio of Ca(OH)2, precursor type and fineness, activator type, activator concentration, and testing age. This review aimed to collect, summarize, and analyze the available studies regarding the effect of Ca(OH)2 on the properties of AAMs in its three forms. The review showed that most studies preferred using Ca(OH)2 as a part of precursor followed by using it as an activator combined with an auxiliary activator, with its use as the sole activator being least preferred. The review found that Ca(OH)2 incorporation in precursors reduced workability and setting time but increased carbonation resistance, with 5-30% Ca(OH)2 being the most effective activator. Auxiliary activator with Ca(OH)2 enhanced the strength. Additionally, some recommendations for the future were mentioned. [ABSTRACT FROM AUTHOR]

In 2020, Denmark buried approximately four million culled, farmed mink in mass graves treated with slaked lime due to widespread SARS-CoV-2 infections. After six months, environmental concerns prompted the exhumation of these cadavers. Our analysis encompassed visual inspections, soil pH measurements, and gas emission assessments of the grave environment. Additionally, we evaluated carcasses for decay status, cadaverine content, and the presence of various pathogens, including SARS-CoV-2 and mink coronavirus. Our findings revealed minimal microbial activity and limited carcass decomposition. Although viral RNA from SARS-CoV-2 and mink coronavirus, along with DNA from Aleutian mink disease virus, were detected, the absence of infectious SARS-CoV-2 in cell culture assays suggests slow natural degradation processes. This study provides critical insights for future considerations in managing mass burial scenarios during outbreaks of livestock-associated zoonotic pathogens. [ABSTRACT FROM AUTHOR]

The aim of this study is to evaluate the effect of different irrigation activation methods on root canal sealer penetration in teeth with simulated internal root resorption (IRR) and calcium hydroxide (CH) applied using a confocal laser scanning microscope (CLSM). 60 incisors with a single root and a single canal were included in the study. IRR cavities were created in the middle third of the root canal, and CH was placed. The samples were randomly divided into 4 groups (n = 15) according to the irrigation activation method to be tested: standard needle irrigation (SNI), sonic activation (EDDY), photon-induced photoacoustic flow (PIPS), and shock wave enhanced emission photoacoustic flow (SWEEPS). After irrigation activation applications, the root canals were obturated. Sections of 1.0 ± 0.1 mm were taken from the apical, middle, and coronal regions of each sample. The penetration area (µm2) and maximum penetration depth (µm) of the root canal sealer were examined by CLSM and analyzed using ImageJ software. Statistical analysis was performed with a one-way ANOVA and post-hoc Tukey test at the P < 0.05 significance level. Among all irrigation activation methods tested, both the penetration area and maximum penetration depth of the root canal sealer were greater in the coronal region than in the apical region (p < 0.05). In the IRR region, there was no difference in terms of maximum penetration depth between PIPS and SWEEPS (p > 0.05), it was highest in SWEEPS (p < 0.05). PIPS and SWEEPS were better than other irrigation activation methods in the penetration of root canal sealer in the resorption areas of teeth with IRR. [ABSTRACT FROM AUTHOR]

Mineral Trioxide Aggregate (MTA) is the gold standard for vital pulp treatment (VPT), but its superiority over novel calcium silicate-based cements in permanent teeth lacks systematic evidence. This study aimed to compare the efficacy of these materials in VPT through a network meta-analysis. A systematic search was conducted in MEDLINE, EMBASE, Cochrane Library, and Web of Science until January 20, 2024. The inclusion criteria were randomized controlled trials involving VPT with biomaterials and reversible or irreversible pulpitis diagnoses in mature permanent teeth. The primary outcome was the odds ratio (OR) of failure rates with 95% confidence intervals. In the 21 eligible trials, failure rates were significantly higher with calcium-hydroxide than MTA at six (OR 2.26 [1.52-3.36]), 12 (OR 2.53 [1.76-3.62]), and 24 months (OR 2.46 [1.60-3.79]). Failure rates for Totalfill at six (OR 1.19 [0.55-2.58]) and 12 months (OR 1.43 [0.71-2.92]), and Biodentine at six (OR 1.09 [0.66-1.78]), 12 (OR 1.21 [0.74-1.96]), and 24 months (OR 1.47 [0.81-2.68]) were not significantly different from MTA. The results were similar in the direct pulp capping subgroup, whereas, in the partial and full pulpotomy subgroup, there was not enough evidence to achieve significant differences. MTA, Biodentine, and Totalfill are the most efficient materials for VPT. However, calcium-hydroxide-based materials are not recommended in VPT. [ABSTRACT FROM AUTHOR]

The combination of multiple factors in marine environments can accelerate the concrete corrosion. In this work, bending fatigue load, dry–wet cycles and Cl− erosion were experimentally combined to evaluate the endurance of marine concrete incorporating nanoparticles (nano-silica (NS) and nano-titania (NT)). Dry–wet cycles of the nano-concretes were simulated in seawater (5% sodium chloride solution) and bending fatigue loads at stress levels of 0.5, 0.6, 0.7 and 0.8 were applied. The results indicated that the nanoparticles enhanced the resistance to Cl− erosion during dry–wet cycles and bending fatigue load by making the concrete more durable under coupled bending fatigue load, dry–wet cycles and Cl− erosion. The improvements were the most obvious for a NT content of 1% and a NS content of 2%, and the improvement was better with 1% NT than with 2% NS content is 2%. The free Cl− content in the concrete tension zone was larger than in the compressive zone. X-ray diffraction was used to assess the physical phases of the concretes before and after the experiments and to analyse the reasons for the increased concrete durability. The nanoparticles increases the content of hydrated calcium silicate in concrete, changed the orientation of calcium hydroxide and improved the concrete durability. [ABSTRACT FROM AUTHOR]

Grouting engineering is extensively employed in highway maintenance, tunnel excavation, mining, and other domains. As application scenarios become more complex, the demands for injectivity and toughness of grouting materials escalate. This research presents the fabrication of a dual-network cementitious material through acrylamide (AM) monomers in-situ polymerization and ultra-fine portland cement for grouting. The in-situ polymerization of AM increases the fluidity of cement paste, forms a hydrogel three-dimensional network structure, and significantly reduces the initial setting time from 345 to 35 min at a 5% AM content. The early-stage compressive strength (0–7 days) is inhibited by the in-situ polymerization, the flexural strength is notably increased, with an overall toughness improvement of 174.4% at a 7% AM content. The in-situ polymerization influences the early hydration behavior of ultra-fine portland cement by delaying the hydration induction period and affecting calcium hydroxide content and the bound water in calcium silicate hydrate. The complexation between metal ions (Ca2+, Al3+) in ultra-fine portland cement and carboxyl groups in the polymer enhances organic–inorganic interaction. The three-dimensional network structure of the cement hydration products and the polymer will form a dual-network structure, further enhancing the performance of the ultra-fine portland cement. In this research, the potential application of AM in-situ polymerization in the enhancement of ultra-fine portland cement grouting is proposed. [ABSTRACT FROM AUTHOR]

In recent years, inorganic nanoparticles, including calcium hydroxide nanoparticles [Ca Ca(OH)2 NPs], have attracted significant interest for their ability to impact plant photosynthesis and boost agricultural productivity. In this study, the effects of 15 and 30 mg L−1 oleylamine-coated calcium hydroxide nanoparticles [Ca(OH)2@OAm NPs] on photosystem II (PSII) photochemistry were investigated on tomato plants at their growth irradiance (GI) (580 μmol photons m−2 s−1) and at high irradiance (HI) (1000 μmol photons m−2 s−1). Ca(OH)2@OAm NPs synthesized via a microwave-assisted method revealed a crystallite size of 25 nm with 34% w/w of oleylamine coater, a hydrodynamic size of 145 nm, and a ζ-potential of 4 mV. Compared with the control plants (sprayed with distilled water), PSII efficiency in tomato plants sprayed with Ca(OH)2@OAm NPs declined as soon as 90 min after the spray, accompanied by a higher excess excitation energy at PSII. Nevertheless, after 72 h, the effective quantum yield of PSII electron transport (ΦPSII) in tomato plants sprayed with Ca(OH)2@OAm NPs enhanced due to both an increase in the fraction of open PSII reaction centers (qp) and to the enhancement in the excitation capture efficiency (Fv'/Fm') of these centers. However, the decrease at the same time in non-photochemical quenching (NPQ) resulted in an increased generation of reactive oxygen species (ROS). It can be concluded that Ca(OH)2@OAm NPs, by effectively regulating the non-photochemical quenching (NPQ) mechanism, enhanced the electron transport rate (ETR) and decreased the excess excitation energy in tomato leaves. The delay in the enhancement of PSII photochemistry by the calcium hydroxide NPs was less at the GI than at the HI. The enhancement of PSII function by calcium hydroxide NPs is suggested to be triggered by the NPQ mechanism that intensifies ROS generation, which is considered to be beneficial. Calcium hydroxide nanoparticles, in less than 72 h, activated a ROS regulatory network of light energy partitioning signaling that enhanced PSII function. Therefore, synthesized Ca(OH)2@OAm NPs could potentially be used as photosynthetic biostimulants to enhance crop yields, pending further testing on other plant species. [ABSTRACT FROM AUTHOR]

Biodiesel, an eco-friendly alternative to conventional fossil fuels, offers reduced emissions like carbon dioxide, sulfur oxides, and soot. This study explores biodiesel production from a blend of waste oils using a novel biomass-based catalyst derived from the bottom ash of a biomass boiler. Catalyst synthesis involved wet impregnation, a unique approach using previously unreported bottom ash. Characterization via SEM-EDS, BET, FTIR, and XRD revealed its composition and structure. Optimization of biodiesel production involved assessing alcohol molar ratio, catalyst concentration, and reaction time, achieving a maximum FAME concentration of 95% under specific conditions. Blending residual palm oil with waste frying oil enhanced biodiesel properties, demonstrating a maximum FAME concentration at specific catalyst concentration (8%), molar ratio (1:10), and reaction time (2 h). Catalyst reusability, up to three cycles without significant yield variation, showcased its sustainability. The catalyst, primarily composed of calcium, a characteristic biomass bottom ash component, exhibited mesoporous features. Impregnation with eggshells not only altered composition but also ensured a uniform particle size distribution. FTIR and XRD analyses indicated calcium in hydroxide and crystallized forms. Effective catalyst separation methods included decanting or water washing, with optimal biodiesel purity achieved through 3% phosphoric acid washing at 60 °C. Various recovery methods were assessed, highlighting hexane washing as the most efficient, enabling up to three catalyst reuse cycles without substantial efficiency loss. [ABSTRACT FROM AUTHOR]

This study investigates the effects of fly ash with a high unburned carbon content as a partial sand replacement material on the properties of mortars. Fly ash was added to the mortar in four different ratios: 0, 10, 30, and 50% by volume. This study examined two series of mortar mix proportions, one having a controlled water-to-cement ratio and the other having a controlled flow. The fresh properties and compressive strength of the mortars were investigated. The experimental results showed that the compressive strength increased with increasing fly ash-to-aggregate ratio (FA/A). However, the increase in FA/A resulted in higher water requirements, lower flow, and longer setting times. The calcium hydroxide content and total porosity of the mortars were also examined to support the results of the compressive strength tests. Based on the results, the FA/A ratio had a significant impact on the fresh properties and compressive strength of the mortars. To ensure fresh properties and compressive strength of mortars, a fly ash-to-sand ratio of up to 30% is recommended. [ABSTRACT FROM AUTHOR]

With the rise in the marine industry and marine tourism, coral powder is increasingly used to make concrete for marine islands. This study proposes a three-parameter hydration model and a hydration kinetic model to predict the performance of coral powder concrete based on previous experimental data. The process of the proposed prediction model is as follows: 1. The input parameters of the three-parameter hydration model are calibrated for the first 7 days using the cumulative hydration heat per gram of cement. The maximum cumulative hydration heat (455.87 J/g cement) and the shape coefficient (−0.87) remain constant. In this study, the hydration rate coefficients for 0%, 10%, and 20% coral powder were 6.91, 6.19, and 5.55, respectively, showing decreases of 10.41% and 19.68% compared with the specimens without coral powder. 2. At 28 days, the cumulative heat release values per gram of cement for 0%, 10%, and 20% coral powder were 389.77, 395.69, and 401.62 J/g, showing increases of 1.52% and 3.04% for the specimens containing 10% and 20% coral powder, respectively. Meanwhile, the hydration degrees for 0%, 10%, and 20% coral powder were 0.855, 0.868, and 0.881, respectively, showing increases of 1.52% and 3.04%. Furthermore, the cumulative heat release values per gram of binder were 389.77, 356.12, and 321.29 J/g, showing decreases of 8.63% and 17.56% for specimens containing 10% and 20% coral powder, respectively. 3. Properties such as compressive strength, ultrasonic pulse velocity (UPV), and surface electrical resistivity were evaluated using the power function and the cumulative hydration heat per gram of binder. 4. At 28 days, the chemically bound water contents for samples with 0%, 10%, and 20% coral powder were 0.2402, 0.2197, and 0.1981 g/g binder, respectively. Moreover, the calcium hydroxide contents were 0.1848, 0.1690, and 0.1524 g/g binder, showing reductions of 8.53% and 17.52% in bound water and 8.54% and 17.53% in calcium hydroxide. 5. A hydration kinetic model is proposed, which can distinguish between the dilution effect and the nucleation effect of coral powder, unlike the three-parameter model, which cannot distinguish between the two effects. Furthermore, the input parameters of the hydration kinetic model remain unchanged for different mixtures, while the input parameters of the three-parameter model must be varied among mixtures. Parameter analysis of the hydration kinetic model indicated that a low water–binder ratio and a high coral powder substitution rate significantly improve the relative reaction level of cement. [ABSTRACT FROM AUTHOR]

Thermochemical energy storage (TCES) presents a promising method for energy storage due to its high storage density and capacity for long-term storage. A combination of TCES and district heating networks exhibits an appealing alternative to natural gas boilers, particularly through the utilisation of industrial waste heat to achieve the UK government's target of Net Zero by 2050. The most pivotal aspects of TCES design are the selected materials, reactor configuration, and heat transfer efficiency. Among the array of potential reactors, the fluidised bed emerges as a novel solution due to its ability to bypass traditional design limitations; the fluidised nature of these reactors provides high heat transfer coefficients, improved mixing and uniformity, and greater fluid-particle contact. This research endeavours to assess the enhancement of thermochemical fluidised bed systems through material characterisation and development techniques, alongside the optimisation of heat transfer. The analysis underscores the appeal of calcium and magnesium hydroxides for TCES, particularly when providing a buffer between medium-grade waste heat supply and district heat demand. Enhancement techniques such as doping and nanomaterial/composite coating are also explored, which are found to improve agglomeration, flowability, and operating conditions of the hydroxide systems. Furthermore, the optimisation of heat transfer prompted an evaluation of heat exchanger configurations and heat transfer fluids. Helical coil heat exchangers are predominantly favoured over alternative configurations, while various heat transfer fluids are considered advantageous depending on TCES material selection. In particular, water and synthetic liquids are compared according to their thermal efficiencies and performances at elevated operating temperatures. [ABSTRACT FROM AUTHOR]

The physicochemical properties of steel slag were investigated using SEM and IR, and it was found that free calcium oxide and free magnesium oxide in steel slag produce calcium hydroxide when in contact with water, leading to volume expansion. Thus, the expansion rate of steel slag itself was first investigated, and it was found that the volume expansion of steel slag was more obvious in seven days after water immersion. Then, the cement dosages of 5% and 6% of the steel slag expansion rate and cement-stabilized gravel volume changes between the intrinsic link were further explored after the study found that the cement bonding effect can be partially inhibited due to the volume of expansion caused by the steel slag, so it can be seen that increasing the dosage of cement can reduce the volume expansion of steel slag cement-stabilized gravel with the same dosage of steel slag. Finally, a prediction model of the expansion rate of steel slag cement-stabilized gravel based on the BP (back propagation) neural network was established, which was verified to be a reliable basis for predicting the expansion rate of steel slag cement-stabilized aggregates and improving the accuracy of the proportioning design. [ABSTRACT FROM AUTHOR]

This study provides experimental insights into the optimization of alkali-activated materials (AAMs) carried out in situ at the restoration site of Monreale Cathedral, Italy. Volcanic ash from Mt. Etna volcano (Italy) was used as a precursor to obtain AAMs. Standard and modified pastes with a small amount of slaked lime paste were compared in terms of setting time, rheology, mineralogy, chemical morphology, and mechanical performance. The modified pastes exhibited a faster setting time, superior mechanical strength and rheological properties. Mineralogically, no difference was observed between the two pastes for the small amount of slaked lime paste added very close to the detectable limit (<2 wt%). Moreover, its addition causes slight differences in the morphology of the gel without changing the chemical composition of the Na 2 O–CaO–Al 2 O 3 –SiO 2 –H 2 O ((N,C)-A-S-H)) type. The results obtained may be useful for the development and optimization of building materials (especially for restoration purposes) where appropriate physico-mechanical performance is required. [Display omitted] [ABSTRACT FROM AUTHOR]

Background: Azathioprine is one of the earliest immunosuppressants prescribed for several autoimmune diseases. Yet there is a lack of research on the impact of azathioprine on pulp healing following the pulp capping procedure. Aim: This study aimed to investigate the effect of azathioprine on the healing ability of mechanically exposed dogs' dental pulps following direct pulp capping with mineral trioxide aggregate (MTA), bio-aggregates (BA), and Calcium hydroxide (Ca(OH)2). Methods: Four mongrel dogs were randomly assigned to two groups (two dogs/30 teeth in each group): immunosuppressed (group I) and control (group II). Group I received azathioprine for two months before surgical treatments and until the dogs were euthanized. Fifteen class V buccal cavities were performed in each dog. Each group was randomly divided into three subgroups (10 teeth each) based on the pulp capping substance. The pulps in subgroups A, B, and C were immediately capped with MTA, BA, and Ca(OH)2, respectively. Inflammation and dentine bridge development were histopathologically evaluated and scored at one and two months. The data were statistically analyzed. Results: The immunosuppressed group exhibited statistically greater inflammatory cell count and decreased dentine bridge thickness, compared to the control group in all subgroups (p < 0.05). Conclusion: Azathioprine has an adverse effect on the healing of exposed dogs' dental pulp following direct pulp capping with MTA, BA, and Ca(OH)2. Therefore, patients using azathioprine as an immunosuppressive medication may experience delayed healing of mechanically exposed pulps following capping with MTA, BA, or Ca(OH)2. [ABSTRACT FROM AUTHOR]

Porous ceramics were synthesized using porcelain tile polishing residue (PTPR) and slaked lime (Ca(OH)2) as a reinforcing agent through a hydrothermal autoclaving method. The process parameters, including the quantity of slaked lime added, the hydrothermal autoclaving temperature, and the reaction duration, were optimized meticulously. The composition, structure, thermal and physical properties of the samples were thoroughly analyzed via Brunauer–Emmett–Teller (BET) measurements, powder X-ray diffraction (PXRD), and scanning electron microscopy (SEM). The results indicated that the incorporation of slaked lime and hydrothermal autoclaving led to the formation of calcium silicate hydrate, which corresponded with an enhancement in the strength of the sample. Notably, when the quantity of slaked lime added was optimized at 30 wt%, the formation of tobermorite (5CaO·6SiO2·5H2O) was detected. At a hydrothermal autoclaving temperature of 150 °C, the formation of only sheet-like calcium silicate hydrate was observed. In contrast, at an elevated temperature of 180 °C and 210 °C, needle-like tobermorite was successfully synthesized. The porous ceramic with the most favorable structure was obtained through autoclaving at 180 °C for 10 h with 30 wt% slaked lime, exhibiting a total pore volume of 0.11 mL/g, a specific surface area of 26.35 m2/g, and a mesoporous volume fraction of 90.40%. [ABSTRACT FROM AUTHOR]

Aim: Design, produce and assess the viability of a novel nanotechnological antibacterial thermo‐sensible intracanal medicament This involves encapsulating calcium hydroxide (Ca(OH)2) within polylactic‐co‐glycolic acid (PLGA) nanoparticles (NPs) and dispersing them in a thermosensitive gel (Ca(OH)2‐NPs‐gel). In addition, perform in vitro and ex vivo assessments to evaluate tissue irritation and penetration capacity into dentinal tubules in comparison to free Ca(OH)2. Methodology: Reproducibility of Ca(OH)₂‐NPs was confirmed by obtaining the average size of the NPs, their polydispersity index, zeta potential and entrapment efficiency. Moreover, rheological studies of Ca(OH)2‐NPs‐gel were carried out with a rheometer, studying the oscillatory stress sweep, the mean viscosity value, frequency and temperature sweeps. Tolerance was assessed using the membrane of an embryonated chicken egg. In vitro Ca(OH)2 release was studied by direct dialysis in an aqueous media monitoring the amount of Ca(OH)2 released. Six extracted human teeth were used to study the depth of penetration of fluorescently labelled Ca(OH)2‐NPs‐gel into the dentinal tubules and significant differences against free Ca(OH)2 were calculated using one‐way anova. Results: Ca(OH)2‐NPs‐gel demonstrated to be highly reproducible with an average size below 200 nm, a homogeneous NPs population, negative surface charge and high entrapment efficiency. The analysis of the thermosensitive gel allowed us to determine its rheological characteristics, showing that at 10°C gels owned a fluid‐like behaviour meanwhile at 37°C they owned an elastic‐like behaviour. Ca(OH)2‐NPs‐gel showed a prolonged drug release and the depth of penetration inside the dentinal tubules increased in the most apical areas. In addition, it was found that this drug did not produce irritation when applied to tissues such as eggs' chorialantoidonic membrane. Conclusion: Calcium hydroxide‐loaded PLGA NPs dispersed in a thermosensitive gel may constitute a suitable alternative as an intracanal antibacterial medicament. [ABSTRACT FROM AUTHOR]

Calcium Hydroxide-based endodontic sealer loaded with antimicrobial agents have been commonly employed in conventional root canal treatment. These sealers are not effective against E. faecalis due to the persistent nature of this bacterium and its ability to evade the antibacterial action of calcium hydroxide. Therefore, endodontic sealer containing Carbon nanodots stabilized silver nanoparticles (CD-AgNPs) was proposed to combat E. faecalis. The therapeutic effect of CD-AgNPs was investigated and a new cytocompatible Calcium Hydroxide-based endodontic sealer enriched with CD-AgNPs was synthesized that exhibited a steady release of Ag+ ions and lower water solubility at 24 hours, and enhanced antibacterial potential against E. faecalis. CD-AgNPs was synthesized and characterized morphologically and compositionally by Scanning Electron Microscopy, Fourier Transform Infrared Spectroscopy (FTIR), and UV-Vis Spectroscopy, followed by optimization via minimum inhibitory concentration (MIC) determination against E. faecalis by broth microdilution technique and Cytotoxicity analysis against NIH3T3 cell lines via Alamar Blue assay. Calcium hydroxide in distilled water was taken as control (C), Calcium hydroxide with to CD-AgNPs (5mg/ml and 10mg/ml) yielded novel endodontic sealers (E1 and E2). Morphological and chemical analysis of the novel sealers were done by SEM and FTIR; followed by in vitro assessment for antibacterial potential against E. faecalis via agar disc diffusion method, release of Ag+ ions for 21 days by Atomic Absorption Spectrophotometry and water solubility by weight change for 21 days. CD-AgNPs were 15–20 nm spherical-shaped particles in uniformly distributed clusters and revealed presence of constituent elements in nano-assembly. FTIR spectra revealed absorption peaks that correspond to various functional groups. UV-Vis absorption spectra showed prominent peaks that correspond to Carbon nanodots and Silver nanoparticles. CD-AgNPs exhibited MIC value of 5mg/ml and cytocompatibility of 84.47% with NIH3T3 cell lines. Novel endodontic sealer cut-discs revealed irregular, hexagonal particles (100–120 nm) with aggregation and rough structure with the presence of constituent elements. FTIR spectra of novel endodontic sealers revealed absorption peaks that correspond to various functional groups. Novel endodontic sealers exhibited enhanced antibacterial potential where E-2 showed greatest inhibition zone against E. faecalis (6.3±2 mm), a steady but highest release of Ag+ ions was exhibited by E-1 (0.043±0.0001 mg/mL) and showed water solubility of <3% at 24 hours where E-2 showed minimal weight loss at all time intervals. Novel endodontic sealers were cytocompatible and showed enhanced antibacterial potential against E. faecalis, however, E2 outperformed in this study in all aspects. [ABSTRACT FROM AUTHOR]

Recent research has increasingly focused on synthesizing nanoparticles (NPs) through various methods to determine how these processes influence their characteristics, and consequently, their biological activity. Calcium zinc hydroxide dihydrate (CaZn2(OH)6·2H2O) nanoparticles, designates as CZ, were obtained via sol–gel (CZ-SG), hydrothermal (CZ-HT), and microwave (CZ-MW) methods, and their properties were characterized using XRD, SEM, TEM, and BET analyses. The different synthesis revealed distinct CZ nanoparticle attributes, including variations in crystallite sizes (72 nm for CZ-SG, 65 nm for CZ-HT and CZ-MW) and morphologies (fibrous for CZ-HT and spherical agglomerates for CZ-SG and CZ-MW). Surface area analysis showed low values across all synthesis methods, with CZ-HT exhibiting the best surface area (8.154 m2/g). The investigation also explored how these synthesis routes influence antifungal efficacy against fourteen fungal strains associated with the biodeterioration of limestone cultural heritage structures. Our results highlight the notable antifungal activity of CZ-NPs, particularly those synthesized via the CZ-HT method, which demonstrated the most effective antifungal action as evidenced by the lowest minimum inhibitory concentration (MIC) and minimum fungicidal concentration (MFC). This effectiveness is attributed to the unique fibrous morphology, which proves to be highly inhibitory to fungal cell proliferation. These findings not only advance our understanding of CZ NPs-mediated antifungal mechanisms but also open a new effort for the development of effective preservation strategies for cultural heritage conservation. [ABSTRACT FROM AUTHOR]

• Single and dual nanoparticle-based treatments are used for preserving materials. • Hardness and erosion properties were improved using these nanoparticles (NPs). • A new C-S-H cementing gel is formed when Ca(OH)2/SiO2 NPs are combined. • The NPs did not significantly alter water vapour permeability. • ΔE was suitable in all cases (0.40–3.79), except for Ca-NPS (5.10). This paper studies the effectiveness of four consolidation treatments based on nanoparticles suspensions: calcium hydroxide (Ca-NP), magnesium hydroxide (Mg-NP), a treatment combining calcium hydroxide and magnesium hydroxide (Ca/Mg-NP), and a treatment consisting of calcium hydroxide and silicon dioxide (Ca/Si-NP) that were both applied separately. The suspensions were sprayed on gypsum plasters and lime renders which are common substrates in historical constructions and show a high degree of similarity with the treatments. The consolidation efficiency was evaluated using non-destructive techniques, such as peeling test, Shore-D hardness, water flow using Karsten tube and water vapour permeability tests. In addition, TEM images and XRD tests demonstrated the formation of a new C-S-H cementing phase when Ca/Si-NPs were combined due to a reaction between Ca(OH) 2 with SiO 2. Colour tests (CIE-L*a*b*) showed the consolidants did not produce major colour alterations, although the Ca-NP treatment caused a slight lightness increase. The strengthening effect was greater in lime mortars and water flow was moderately reduced in all treatments, except in mortars coated with Ca/Mg-NP. Finally, the chemical nature of the treatments is similar to the substrates, and they did not significantly alter the water vapour permeability of the studied materials. [ABSTRACT FROM AUTHOR]

Herein, a new template carbonization method is used to prepare calcite‐type nano‐calcium carbonate (CaCO3) with a core–shell structure using calcium hydroxide as a solute and Pluronic F‐127 as a templating and pore‐forming agent. Dopamine hydrochloride is added to control the size of calcium hydroxide particles. The morphology, particle size, and crystal type of CaCO3 are characterized via transmission electron microscopy, X‐ray diffraction, nanoparticle size, and zeta potentiometer. The creation of core–shell calcium carbonate nanoparticles is examined in relation to reaction circumstances (i.e., additive sequence, additive amount, and additive mixing time), carbonization temperature, liquid flow rate, and templates with varying chain lengths. Furthermore, a discussion is held regarding the formation mechanism of spherical core–shell calcium carbonate that is created using the innovative template carbonization method. The results show that the order, amount, liquid flow rate, and template type of additives have a significant effect on the crystal shape of calcium carbonate nanoparticles. The mixing time of additives has a significant effect on the particle size of calcium carbonate nanoparticles. Interestingly, the thickness of the shell depends on the carbonization temperature, and too slow or too fast flow rate will lead to the formation of cyclic calcium carbonate nanoparticles. [ABSTRACT FROM AUTHOR]

Objectives: This randomized clinical trial aimed to compare the effect of intracanal medicaments on the incidence of postoperative pain and flare-up with posttreatment apical periodontitis (PTAP) of retreatment cases. Materials and methods: One hundred twenty patients diagnosed with PTAP with single-rooted teeth with single-canal without spontaneous pain or swellings were included and randomly divided into three groups according to the intracanal medicament used. Intracanal medicaments were placed into the root canals following the removal of previous root canal fillings and re-instrumentation. Calcium hydroxide (Ca (OH)2), chlorhexidine gel (CHX), calcium hydroxide and chlorhexidine gel combinations were used as intracanal medicaments. Postoperative pain scores were recorded at 6 and 12 h and 1, 2, 3, 4, 5, 6, and 7 days using a visual analog scale (VAS). Sensitivity on percussion, spontaneous pain, swelling, antibiotic and analgesic requirements of the patients were evaluated during clinical examinations performed postoperatively after 2 and 7 days. Results: There were no statistically significant differences between groups in terms of VAS scores following the intracanal medicament application (p > 0.05). However, compared to the patients of 20–34 and 50–65 age groups, greater VAS scores were observed in patients of 35–49 age groups at 12 h, and 3, 4, 7 days (p < 0.05). Flare-up was observed in only one patient in the CHX gel group, and no flare-up was observed in other groups. Conclusions: Similar postoperative pain incidence in all experimental groups indicates that all three medicaments are clinically acceptable in inter-appointment management of retreatment cases in terms of post-endodontic pain and flare-up. Clinical relevance: In this randomized clinical trial, three different intracanal medicaments were utilized in nonsurgical endodontic retreatment and their effect on postoperative pain and flare-up incidence was examined. Thus, this study will be a significant contribution in the decision-making during clinical practice; since there are a limited number of prospective clinical trials in the literature about the severity of pain following retreatment procedures including intracanal medicament use. [ABSTRACT FROM AUTHOR]

Objective: To investigate the effectiveness of Er:YAG laser-activated irrigation (LAI) with a short pulse duration for removing calcium hydroxide (CH) from simulated internal root resorption (IRR) cavities at three root levels. Background: Pulse duration is an important parameter during LAI, which ensures the efficiency of irradiation and the corresponding activation process. Short pulses in the range of a few microseconds enable rapid expansion and successive implosion of irrigants, resulting in distinct fluid movement. There have been few reports on CH removal efficacy from IRR cavities of different LAI systems, including those using short pulse duration. Methods: IRR cavities (1.6 mm diameter) were created at the apical, middle, and coronal root levels in 60 mandibular premolars and filled with a radiopaque CH paste. Samples were assigned to the following irrigation groups (n = 12, each): (1) LAI(P)-F, a prototype laser device that operates with short pulse duration (Morita Manufacturing) with a flat tip; (2) LAI(EA)-F, the ErwinAdverl laser device (Morita Manufacturing) with a flat tip; (3) LAI(EA)-T, the ErwinAdverl laser device with a tapered tip; (4) PIPS-T, the Lightwalker laser device (Fotona) with a tapered tip; and (5) SI, the syringe irrigation group. The laser tips were fixed at the canal entrance. The remaining CH volume and surface area were assessed in IRR cavities using micro-computed tomography and scanning electron microscopy, respectively. Data were statistically analyzed utilizing one-way analysis of variance and Tukey’s test at 5% significance level. Results: The LAI(P)-F and PIPS-T groups exhibited the highest CH removal rates at three different levels (p < 0.05). The LAI(EA)-F group had a significantly better efficacy of CH removal compared with the LAI(EA)-T group at the middle level (p < 0.05). Conclusion: The LAI(P)-F and PIPS-T groups demonstrated superior efficiency in removing CH from simulated IRR cavities. [ABSTRACT FROM AUTHOR]

Microbial self-healing concrete (MSHC) is an eco-friendly material that supports low-carbon development. However, the formation mechanism of calcium carbonate (CaCO3) in MSHC remains unclear. This study investigated the formation process of CaCO3 clusters in MSHC using molecular simulation. The hydroxide ion and carbonate ion (CO32−) would compete for association with calcium ion in MSHC. The formation process of CaCO3 clusters could be summarised as follows: free ions first associated to form ion pairs, then ion pairs aggregated into small clusters through ion-dipole interactions, and finally, small clusters overcame the surface charge effect by high-frequency aggregation-separation behaviour to transform into large clusters and further densify themselves. The reaction rate of CaCO3 cluster formation decreased significantly with the decrease of CO32− concentration, and the association between calcium ion and hydroxide ion would dominate when the CO32− concentration was low. [ABSTRACT FROM AUTHOR]

Background: The present study evaluated the effect of a bioceramic intracanal medicament (Bio-C Temp) on the push-out bond strength of bioceramic cements. Methods: Forty-eight human single-canaled premolars were prepared and randomly divided into three groups: Group (A) received no intracanal medicament; Group (B) calcium hydroxide (CH); and Group (C) Bio-C Temp. After medicament removal, the roots were sectioned transversely. The slices in each group were separated into two subgroups (n = 16): in Subgroup (1), mineral trioxide aggregate (MTA) was placed, and in Subgroup (2) Bio-C Repair. Push-out bond strength was determined using a universal testing machine, applying a constant compressive force on the cement until bond failure. The failure mode was also evaluated. Data were analyzed using the Chi-square test and two-way ANOVA followed by Tukey's post hoc tests. The level of significance was set at 5%. Results: The pushout bond strength of Bio-C Repair was significantly higher than that of MTA irrespective of intracanal medication (p = 0.005). The placement of Bio-C Temp was associated with significantly lower bond strength (p = 0.002, p = 0.001). Conclusion: Bio-C Repair showed better bond strength compared to MTA, irrespective of intracanal medication. Bio-C Temp intracanal medicament, however, decreased the bond strength of both these cements. [ABSTRACT FROM AUTHOR]

This study explored the antimicrobial effects of ketoprofen, piroxicam, and celecoxib alone or combined with calcium hydroxide (CH) against two strains of Enterococcus faecalis (E. faecalis) and assessed the influence of such combinations on the pH of CH. Minimum inhibitory concentrations (MICs) of the three tested NSAIDs were determined. Tested pastes were placed into wells punched in seeded agar plates and the bacterial inhibition zones were measured. Antibiofilm activity was assessed against 3 weeks of biofilm induced in bovine dentine blocks. The pH of the pastes was measured at four-time intervals. MIC values were 3.12, 25, and 25 mg/ml for ketoprofen, piroxicam, and celecoxib, respectively, and were similar for both bacterial strains except for celecoxib, which showed 8% growth at the highest tested concentration against vancomycin-resistant E. faecalis. Ketoprofen had the largest mean inhibition zone that was comparable to CH. None of the six tested pastes exhibited antibiofilm activity of a significant level in comparison to CH. A noticeable increase in the antibiofilm activity was found when 20% NSAIDs were added to CH while maintaining an alkaline pH. Ketoprofen was found to be the most effective among the tested NSAIDs. Although its effect was comparable to CH, adding ketoprofen at a ratio of 20% resulted in 50% higher antimicrobial action than CH alone. Accordingly, incorporating NSAIDs in inter-appointment dressing has the potential to utilize their anti-inflammatory, local analgesic, and antibacterial actions, which overcome the limitations of CH and improve the outcome of root canal treatment. [ABSTRACT FROM AUTHOR]

To evaluate and compare the effect of calcium hydroxide [Ca(OH)2] and 2-hydroxyisocaproic acid (HICA) on the microhardness of root dentine. Fifty-one matured maxillary central incisors with straight root and type I canal configuration were decoronated to a standardized length of 16 mm. The root canals were cleaned and shaped using rotary instruments up to size F5. The tooth samples were then randomly assigned into three groups (n = 17) based on the intracanal medicament placed. Group A: control group with no intracanal medicament, Group B: root canals placed with Ca(OH)2, and Group C: root canals placed with HICA. After 1 week, the intracanal medicaments placed within the root canals were removed and the canals were dried. Subsequently, the specimens were split longitudinally into two halves and subjected to the Vickers microhardness test with indentations made at the coronal, middle, and apical-third root regions. The data were analyzed using one-way ANOVA and Tukey's post hoc tests. The control group showed significantly highest microhardness value (P < 0.001), followed by HICA and finally, Ca(OH)2 at the coronal, middle, and apical-third root regions, respectively. Nonetheless, there were no statistically significant differences in microhardness values across different root regions within each group. HICA was found to have a significantly lesser reduction in root dentine microhardness which could be a potential alternative to Ca(OH)2. Nevertheless, future studies are warranted to verify the present outcomes in the clinical setting. [ABSTRACT FROM AUTHOR]

Calcium hydroxide represents the most commonly used intracanal dressing between sessions; however, it may not be effective against all types of microorganisms. Several compounds of plant origin have attracted increasing attention from researchers in recent years. The objective of this study was to evaluate the cytocompatibility and antimicrobial activity of calcium hydroxide associated with the essential oil of Cyperus articulatus and the new bioceramic intracanal medicament Bio-C Temp®. Five experimental groups were designed: group Ca–C. articulatus essential oil; group CHPG-calcium hydroxide associated with propylene glycol; group CHCa-essential oil of C. articulatus associated with calcium hydroxide; and group U-UltraCal® XS; group BCT-Bio-C Temp®. The control group was a culture medium. Cytocompatibility was assessed by the methyltetrazolium (MTT) assay after exposure of the Saos-2 human osteoblast-like cell line to dilutions of commercial products/associations for 24 h and 72 h. The antimicrobial activity against mature Enterococcus faecalis biofilm was evaluated by the crystal violet assay. All commercial products/associations showed a cell viability similar to or even higher than the control group (p > 0.05) for both periods evaluated. C. articulatus essential oil associated or not with calcium hydroxide showed better antibiofilm capacity. C. articulatus associated or not with calcium hydroxide showed superior cytocompatibility and antimicrobial capacity, representing a promissory intracanal medicament. [ABSTRACT FROM AUTHOR]

Aim: The aim of the study was to assess and evaluate the antimicrobial effectiveness of chitosan nanoparticles (CSNPs) with calcium hydroxide in the elimination of Enterococcus faecalis. Materials and Methods: Using the broth microdilution method, the minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of calcium hydroxide and CSNPs were measured. The antibiofilm effect of calcium hydroxide and CSNPs against E. faecalis biofilm was qualitatively analyzed using a crystal violet assay. A 7-day-old biofilms of E. faecalis grown on dentine discs were assigned to the following three groups (n = 11 dentine discs), normal saline (group I), calcium hydroxide (group II), and CSNPs (group III). Quantification of live and dead cells using confocal microscopy was done to evaluate the antibiofilm efficacy of the medicaments included in the study. Results: MIC of calcium hydroxide and CSNPs against E. faecalis was observed at 2.5 mg/mL and 0.31 mg/mL, respectively. MBC of calcium hydroxide and CSNPs was observed at 2.5 mg/mL and 0.31 mg/mL, respectively. Using Crystal Violet (CV) assay, calcium hydroxide and CSNPs showed biofilm inhibition at concentrations of 2.5 mg/mL and 0.625 mg/mL, respectively. Confocal laser scanning microscopy analysis found that both calcium hydroxide and CSNPs showed a significant decrease in viable cells at their MBC values compared to the control group's normal saline. CSNPs showed a significantly lower percentage of live cells than calcium hydroxide (P < 0.05). Conclusion: The study results reveal that the antimicrobial efficacy of CSNPs is better than calcium hydroxide and normal saline against E. faecalis biofilm. [ABSTRACT FROM AUTHOR]

Background: Antibiotic pastes used as intracanal medication in cases of revascularization therapy might cause negative effects on tooth properties, such as a reduction in dentin microhardness. This in vitro study investigated dentin microhardness in three different locations distancing from the canal lumen after 20 days of treatment with a tri-antibiotic paste (ciprofloxacin, metronidazole, and minocycline), and with a double-antibiotic paste (ciprofloxacin and metronidazole), with calcium hydroxide [Ca(OH)2] UltracalTM XS-treated dentin as comparison. Material and Methods: Human mandibular premolars (n = 48) had the root canals cleaned and shaped and were used to produce dentin slices. Dentin slices remained immersed in the medications for 20 days. The Knoop microhardness (KHN) test was performed before (baseline/Day-0) and after treatment (Day-20) with the medications. Indentations were made at 25 µm, 50 µm, and 100 µm distances from the root canal lumen. The KHN was compared intra-group using Wilcoxon's test. Independent groups were compared using Mann–Whitney's and Kruskal–Wallis' tests, at α = 5%. Results: The microhardness in all the tested groups was reduced at Day-20 in comparison with Day-0 (p < 0.001) (intra-group comparison/same distances). The Day-0 values were similar, and the Day-20 values were higher for the Ca(OH)2 group (p < 0.05) (comparison between groups/same distances). Conclusions: Calcium hydroxide for 20 days would be preferred rather than antibiotic pastes to minimize the expected reduction in dentin microhardness during regenerative procedures. [ABSTRACT FROM AUTHOR]

Purpose: Nowadays, regenerative endodontics treatment is recommended in the case of loss of vitality of the dental pulp and the presence of a suitable dental structure. One of the primary reasons for failure after regenerative endodontics treatments is the remaining of bacteria in the root canal. Thus, to improve the prognosis of root canal treatment, it is recommended to use different intracanal medicaments including antibiotics and calcium hydroxide as complementary agents. This study aimed to review common intracanal medicaments in the treatment of endodontic regeneration. Materials and Methods: In this review study, the keywords of regenerative endodontics, pulp revascularization, paste antibiotic, intracanal medicament, and calcium hydroxide were searched in the Google, Google Scholar, PubMed, SID, ISI Web of Science, and IranMedex databases from 2018 to 2023. Articles that met the inclusion criteria were included in this study. Results: 39 studies were included in this study. Common intracanal medicaments (triple, double antibiotic pastes, calcium hydroxide, etc.) that are commonly used in regenerative endodontic treatment were used. Both the concentration and duration of exposure to the medicaments affect the viability of stem cells. TAP (Triple Antibiotic Paste) has the highest antibacterial effect against E. faecalis and the highest rate of discoloration. Calcium hydroxide as a medicament will probably have a positive impact on the release of growth factors. Conclusion: It is better to use antibiotic medicaments with a lower concentration at times between 24 hours and 48 hours for dental root canal disinfection so it does not interfere with the viability of stem cells. [ABSTRACT FROM AUTHOR]

Nano-calcium carbonate (NC) is a novel ultrafine solid powder material that possesses quantum size effects, small size effects, surface effects, and macroscopic quantum effects that ordinary calcium carbonate lacks. As a nanomaterial with superior properties, graphene oxide (GO) has been studied extensively in the field of construction. In microscopic characterization, the reaction between NC and tricalcium aluminate (C3A) formed a new hydration product, hydrated calcium aluminum carbonate (C3A·CaCO3·11H2O), which enhanced the arrangement of hydration products and optimized the distribution of pore size in the mortar. Regarding the mechanical properties, the addition of GO and NC significantly enhanced the early-age mechanical performance of the mortar. In terms of durability, the incorporation of GO and NC significantly improved the water permeability, chloride ion permeability, and resistance to sulfate attack of the cement mortar. In this study, it was found that adding 1 wt% NC and 0.02 wt% GO not only improves the mechanical and durability properties but also promotes the hydration reaction according to the microstructure analysis. With the help of NC, compared with other studies, the amount of GO is reduced, while the cost is reduced, and the application of GO in the field of cement-based materials is promoted. [ABSTRACT FROM AUTHOR]

This study aims to propose a hydration kinetic model for the cement–eggshell powder binary system and predict the performance development of composite concrete through this model. The specific content and results of the model are as follows. First, based on the cumulative hydration heat of the cement and eggshell powder binary system in the first seven days, the parameters of the cement hydration model and the eggshell powder nucleation parameter are calibrated. These parameters remain constant regardless of the mix ratio. Secondly, the hydration heat of the cement–eggshell powder binary system over 28 days is calculated using the hydration model. The results show that at 28 days, for specimens with 0%, 7.5%, and 15% eggshell powder substitution, the cement hydration degrees are 0.832, 0.882, and 0.923, respectively. The hydration heat per gram of cement is 402.69, 426.88, and 446.73 J/g cement, respectively, while the hydration heat per gram of binder is 402.69, 394.86, and 379.72 J/g binder, respectively. Additionally, the hydration model is used to calculate the chemically bound water and calcium hydroxide content of the cement–eggshell powder binary system. At 28 days, for samples with 0%, 7.5%, and 15% eggshell powder, the chemically bound water content is 0.191, 0.188, and 0.180 g/g binder, respectively, and the calcium hydroxide content is 0.183, 0.179, and 0.173 g/g binder, respectively. Finally, a power function is used to regress the calculated hydration heat with experimentally measured compressive strength and surface electrical resistivity. The correlation coefficients for compressive strength and surface electrical resistivity are 0.8474 and 0.9714, respectively. This is because the strength weak point effect of eggshell powder has minimal impact on hydration heat and surface electrical resistivity experiments but significantly affects the strength experiment. [ABSTRACT FROM AUTHOR]

The use of alumina-containing nepheline raw materials as an alternative source of alumina is relevant in the context of the limited bauxite reserves in Kazakhstan. Nepheline processing can result in products such as alumina, sodium and potassium salts, silicate products and rare metals. In terms of economic value, alumina is the most important. This article considers an advanced technology for nepheline processing for the extraction of alumina that is first purified from potassium. The application of calcium sulphate and calcium oxide as additives to the nepheline raw materials is studied. The optimal conditions for two-stage leaching with calcium additives in the form of calcium sulphate and calcium hydroxide are determined. [ABSTRACT FROM AUTHOR]

The presence of cobalt ions Co(II) in wastewater poses major threats to both humans and the environment. The effectiveness of the adsorption of modified quartz rock particles (MQRP) adsorbent with calcium hydroxide solution Ca(OH)2 for eliminating Co(II) from a water solution was examined. MQRP had a maximum ability to adsorb 47.112 mg g−1 for Co(II) at pH 6.0 and a contact time of 2 h. The HCl stripping agent offered the highest desorption efficiency to regenerate the adsorbent for use again for a new cycle of adsorption. The equilibrium isotherms of the adsorption characteristics were experimentally identified, and the results of adsorption aligned with the principles of the Langmuir model. Under the examined temperature conditions, thermodynamic evaluation proved that Co(II) adsorption on adsorbent vacancies was spontaneous and exothermic. The outcomes of the kinetic process demonstrated that the process closely conformed to a pseudo-secondorder pattern. Therefore, the high silica content of MQRP makes it an important adsorbent, and it could be applied as a cost-effective and efficient adsorbent to control the release of Co(II) ions in industrial wastewater. [ABSTRACT FROM AUTHOR]

The evolution of biomaterials engineering allowed for the development of products that improve outcomes in the medical–dental field. Bioglasses have demonstrated the ability to either compose or replace different materials in dentistry. This study evaluated the cytotoxicity, biocompatibility, calcium deposition, and collagen maturation of 45S5 bioglass experimental paste and Bio-C Temp, compared to calcium hydroxide (Ca(OH)2) paste. The 45S5 bioglass and Ca(OH)2 powder were mixed with distilled water (ratio 2:1); Bio-C Temp is ready-for-use. Dental pulp cells were exposed to the materials' extracts (1:2 and 1:4 dilutions; 24, 48, and 72 h) for MTT and live/dead analyses. Polyethylene tubes filled with the pastes, or left empty (control), were implanted on the dorsum of 16 rats. After 7 and 30 days (n = 8/period), the rats were euthanized and the specimens were processed for hematoxylin–eosin (H&E), von Kossa (vK), and picrosirius red (PSR) staining, or without staining for polarized light (PL) birefringence analysis. A statistical analysis was applied (p < 0.05). There was no difference in cell viability among Ca(OH)2, 45S5 bioglass, and the control, across all periods and dilutions (p > 0.05), while Bio-C Temp was cytotoxic in all periods and dilutions compared to the control (p < 0.05). Regarding biocompatibility, there was a reduction in inflammation from 7 to 30 days for all groups, without significant differences among the groups for any period (p > 0.05). The fibrous capsules were thick for all groups at 7 days and thin at 30 days. All materials showed positive structures for vK and PL analysis. At 7 days, the control and 45S5 bioglass showed more immature collagen than the other groups (p < 0.05); at 30 days, 45S5 bioglass had more immature than mature collagen, different from the other groups (p < 0.05). In conclusion, Bio-C Temp presented cytotoxicity compared to the other materials, but the three pastes showed biocompatibility and induced calcium deposition. Additionally, the bioglass paste allowed for marked and continuous collagen proliferation. This study contributed to the development of new biomaterials and highlighted different methodologies for understanding the characteristics of medical–dental materials. [ABSTRACT FROM AUTHOR]

Background. Minimally invasive endodontics is recommended for young, immature teeth to preserve healthy pulp and dentin tissue. Objectives. The aim of the study was to examine the cold sensitivity of immature teeth that received photobiomodulation (PBM) after vital pulp therapy (VPT). Materials and methods. The study followed the STROBE guidelines and included 123 healthy patients aged 8--13. The immature teeth (incisors, premolars and molars) that qualified for VPT received the bioc- eramic material -- Biodentine. In this experiment, teeth were treated immediately and at 24 h post-VPT with a 635-nm diode laser using a power of 100 mW, a power density of 200 mW/cm2 and a total energy of 4 J (PBM group, n = 43), while those not treated were the control group (n = 43). The tooth sensitivity to cold was measured using a visual analogue scale (VAS) before and at 6 h, 1 day, 7, 30, and 90 days after treatment. The predictor variable was PBM skills regarding the ability to decrease cold sensitivity after VPT. The primary endpoint was the time to reverse hypersensitivity to cold, and the secondary endpoint was the occurrence of possible side effects. The Mann--Whitney U test, Friedman test along with Dunn's post hoc test, and the χ² test were used to investigate tooth sensitivity. Results. Eighty-six immature permanent teeth of 86 children were included in the study. It was shown that the difference was significant for sensitivity to a cold stimulus between the groups at 6 h, 24 h, 7 days, and 30 days, but no difference was found preoperatively and at 90 days (6 h, 24 h, 7 days, and 30 days, p < 0.001, and 90 days, p = 0.079). However, patients in both groups reported a decrease in discomfort provoked by cold stimuli throughout the follow-up period. Conclusions. Photobiomodulation decreased postoperative sensitivity and was more acceptable for patients. Further randomized clinical studies with placebo-controlled groups are needed. [ABSTRACT FROM AUTHOR]

Abstract With the development of industry and agriculture, eutrophication caused by increasing amounts of phosphorus in the environment has attracted people's attention. On the other hand, copper tailings (CT) is a kind of solid waste with large quantity, large area, and easy to cause groundwater and soil pollution. CT is also a potential resource because of its large specific surface area. CT is intended to be used as an adsorbent for removal phosphate in water, but trace heavy metals and a small amount of phosphate in CT may bring negative effects. Calcium hydroxide (Ca(OH)2) was used to modify CT (CCT), hoping to fix the heavy metals and phosphate in CT at the same time. It was found that the removal capacity of CCT was significantly higher than that of CT. The process of phosphate removal by CCT involves electrostatic sorption and surface precipitation, and there is a synergistic effect between CT and Ca(OH)2. The phosphate removal rate of CCT-0.4 increased with the increase of pH value under alkaline conditions. The XRD patterns of phosphate sorption by CCT mean that Ca3(PO4)2, Ca5(PO4)3(OH) and AlPO4 exist in CCT after phosphate removal, indicating that surface precipitation occurs during the removal process. In summary, the removal mechanism of phosphate by CCT is mainly electrostatic attraction and surface precipitation.

Abstract Mineral Trioxide Aggregate (MTA) is the gold standard for vital pulp treatment (VPT), but its superiority over novel calcium silicate-based cements in permanent teeth lacks systematic evidence. This study aimed to compare the efficacy of these materials in VPT through a network meta-analysis. A systematic search was conducted in MEDLINE, EMBASE, Cochrane Library, and Web of Science until January 20, 2024. The inclusion criteria were randomized controlled trials involving VPT with biomaterials and reversible or irreversible pulpitis diagnoses in mature permanent teeth. The primary outcome was the odds ratio (OR) of failure rates with 95% confidence intervals. In the 21 eligible trials, failure rates were significantly higher with calcium-hydroxide than MTA at six (OR 2.26 [1.52-3.36]), 12 (OR 2.53 [1.76-3.62]), and 24 months (OR 2.46 [1.60-3.79]). Failure rates for Totalfill at six (OR 1.19 [0.55-2.58]) and 12 months (OR 1.43 [0.71-2.92]), and Biodentine at six (OR 1.09 [0.66-1.78]), 12 (OR 1.21 [0.74-1.96]), and 24 months (OR 1.47 [0.81-2.68]) were not significantly different from MTA. The results were similar in the direct pulp capping subgroup, whereas, in the partial and full pulpotomy subgroup, there was not enough evidence to achieve significant differences. MTA, Biodentine, and Totalfill are the most efficient materials for VPT. However, calcium-hydroxide-based materials are not recommended in VPT.

Background: Azathioprine is one of the earliest immunosuppressants prescriped for several autoimmune diseases. Yet there is a lack of research on the impact of azathioprine on pulp healing following pulp capping procedure. Aim: This study aimed to investigate the effect of azathioprine on the healing ability of mechanically exposed dogs' dental pulps following direct pulp capping with Mineral Trioxide Aggregate (MTA), Bio-Aggregates (BA), and Calcium hydroxide (Ca(OH)2). Methods: Four mongrel dogs were randomly assigned to two groups (2 dogs/30 teeth in each group): immunosuppressed (group I) and control (group II). Group I received azathioprine for two months before surgical treatments and until the dogs were euthanized. Fifteen class V buccal cavities were performed in each dog. Each group was randomly divided into three subgroups (10 teeth each) based on the pulp capping substance. The pulps in subgroups A, B, and C were immediately capped with MTA, BA, and Ca(OH)2, respectively. Inflammation and dentine bridge development were histopathologically evaluated and scored at one and two months. The data were statistically analyzed. Results: The immunosuppressed group exhibited statistically greater inflammatory cell count and decreased dentine bridge thickness, compared to the control group in all subgroups (P [Open Vet J 2024; 14(7.000): 1614-1624]