Cement Research Articles

Utilization of cement deep mixing pile for soft soil foundation: a malaysian case study

Cement deep mixing piles, as representatives of deep mixing technology, are mature and widely applied. However, effective application cases of cement deep mixing piles are relatively scarce in countries like Malaysia in Southeast Asia. In this paper, the application of cement deep mixing pile reinforcement in Malaysia is presented. Solidifying material was selected for deep mixing piles based on the soil conditions using unconfined compressive strength (UCS) tests. The relationship between the strength of deep mixing piles on-site and soil properties (type, organic matter content, and ion content) was analyzed. And a quality evaluation of the deep mixing piles in the project is conducted based on Kolmogorov-Smirnov (K-S) tests and relevant standards. Results show that fly ash cement is suitable as a solidifying agent for acidic soil layers containing organic matter in the local area. The strength of piles is significantly related to the soil condition. The UCS of cement mixing piles in silty clay and peat soils is smaller than clay. The overall correlation between organic matter content in the soil and UCS is negative, particularly when the organic matter content ranges from 10% to 14%, resulting in a significant drop in UCS. The bilateral significance probability is greater than 0.05 in K-S test, indicating that the UCS results in the projectconform to a normal distribution. Additionally, the evaluation of the overall quality of the mixing piles aligns with the requirements in the Japanese standard “Manual of Deep Mixing Construction Technology for Harbors and Airports” and the Chinese standard “Technical Code for Building Foundation Detection”.

Utilization or Sequestration for Captured CO2 from Cement Plants?

Utilization or Sequestration for Captured CO₂ from Cement Plants?

Enhancing the Biological Properties of Organic–Inorganic Hybrid Calcium Silicate Cements: An In Vitro Study

(1) Background: This study aimed to enhance the biological properties of hydraulic calcium silicate cements (HCSCs) by incorporating organic and inorganic components, specifically elastin-like polypeptides (ELPs) and bioactive glass (BAG). We focused on the effects of these composites on the viability, migration, and osteogenic differentiation of human periodontal ligament fibroblasts (hPDLFs). (2) Methods: Proroot MTA was supplemented with 1–5 wt% 63S BAG and 10 wt% ELP. The experimental groups contained various combinations of HSCS with ELP and BAG. Cell viability was assessed using an MTT assay, cell migration was evaluated using wound healing and transwell assays, and osteogenic activity was determined through Alizarin Red S staining and a gene expression analysis of osteogenic markers (ALP, RUNX-2, OCN, and Col1A2). (3) Results: The combination of ELP and BAG significantly enhanced the viability of hPDLFs with an optimal BAG concentration of 1–4%. Cell migration assays demonstrated faster migration rates in groups with 2–4% BAG and ELP incorporation. Osteogenic activity was the highest with 2–3% BAG incorporation with ELP, as evidenced by intense Alizarin Red S staining and the upregulation of osteogenic differentiation markers. (4) Conclusions: The incorporation of ELP (organic) and BAG (inorganic) into HCSC significantly enhances the viability, migration, and osteogenic differentiation of hPDLFs. These findings suggest that composite HCSC might support healing in destructed bone lesions in endodontics.

3D Numerical Investigation of Soil Arching in Deep Cement Mixing and Stiffened Deep Cement Mixing Pile-Supported Embankments

3D Numerical Investigation of Soil Arching in Deep Cement Mixing and Stiffened Deep Cement Mixing Pile-Supported Embankments

Review of Power-to-Liquid (PtL) Technology for Renewable Methanol (e-MeOH): Recent Developments, Emerging Trends and Prospects for the Cement Plant Industry

The cement industry is a significant contributor (around 8%) to CO2 global emissions. About 60% of the industry’s emissions come from limestone calcination, which is essential for clinker production, while 40% are the result of fuel combustion. Reducing these emissions is challenging due to limestone’s role as the primary raw material for cement. Cement plants are required to achieve carbon neutrality by 2050, as outlined in the 13th United Nations Sustainable Goals. One strategy to achieve this goal, involves Carbon Capture and utilization (CCU). Among the options for CO2 utilization, the Power-to-Liquid (PtL) strategy offers a means to mitigate CO2 emissions. In PtL, the CO2 captured from cement industrial flue gas is combined with the hydrogen generated by renewable electrolysis (green hydrogen) and is catalytically converted into renewable methanol (e-MeOH). In this sense, this review provides a comprehensive overview of the worldwide existing pilot and demonstration units and projects funded by the EU across several industries. It specifically focuses on PtL technology worldwide within cement plants. This work covers 18 locations worldwide, detailing technology existent at plants of different capacities, location, and project partners. Finally, the review analyses techno-economic assessments related to e-MeOH production processes, highlighting the potential impact on achieving carbon neutrality in the cement industry.

ABSORPTION REFRIGERATION SYSTEMS FOR WASTE HEAT RECOVERY AT THE SILICATE INDUSTRY

The glass, ceramic and cement plants are energy intensive industrial systems, releasing high amounts of greenhouse gases. The dissipation of the waste heat reduces their profitability, energy and ecological efficiency. The absorption refrigeration systems are successful solutions for the recovery of thermal energy at different temperature levels to obtain useful cooling and heating powers for technological needs, and for air conditioning of administrative and industrial buildings. Although the absorption units in a heat pump and refrigeration cycle are currently used in building and industrial systems, they have not yet penetrated widely into the silicate factories. This paper discusses possibilities for the applications of basic types of absorption cycles at heat pump and refrigeration modes to utilize waste energy at different temperature levels in glass, ceramic and cement plants. The examined variants are demonstrated via examples, diagrams and analyses of the possible energy saving.

An investigation into the microstructural evolution and shrinkage control in internally cured mortars with milkweed fibres

This study presented a significant advancement in the use of Milkweed (MW) fibres as internal curing agents in low water-to-cement (w/c) cementitious materials. The research focused on how different pre-treated MW fibres, with different composition, can impact internal curing efficacy in reducing autogenous shrinkage of cement mortars. In addition, the hydration behaviour and microstructural development were revealed using a series of tests including setting time, compressive strength, flexural strength, scanning electron microscopy (SEM), and thermogravimetric analysis (TGA/DTG). A key finding of this study is the remarkable reduction in autogenous shrinkage, with using 0.1 % wt. pre-treated MW fibres leading to up to 28 % reduction at 7 days, compared to plain mortars. Furthermore, internal curing effect resulted in narrowing the compressive strength gap between the reference mixes and those with pre-treated MW fibres in the later stages of hydration. It was also found that the removal of hemicellulose through hybrid treatment can reduce the delay in the final setting time of cement from 45 minutes to 18 minutes. Additionally, while the incorporation of N- and HT-treated MW fibres had negligible effects on drying shrinkage, the inclusion of HY-treated MW fibres led to a 15 % increase in drying shrinkage at 7 days. This difference in behaviour was attributed to the presence of lignin in N- and HT-treated fibres. Lignin was found to play a crucial role in influencing the drying shrinkage, microstructural development, and mechanical properties of MW fibre-incorporated cementitious mixes. Acting as a protective barrier, lignin shielded the MW fibres from cement infiltration into their lumina. Moreover, it served as both a physical and chemical barrier, reducing moisture transport through the capillary network during drying. In conclusion, this study demonstrated the potential of using pre-treated MW fibres as internal curing agents to effectively reduce autogenous shrinkage, with minimal compromise in terms of the compressive strength of cementitious composites.

Optimisation and Composition of the Recycled Cold Mix with a High Content of Waste Materials

This research focuses on a mineral–cement mixture containing bitumen emulsion, designed for cold recycling procedures, the formulation of which includes 80% (m/m) of waste material. Deep cold recycling technology from the MCE mixture guarantees the implementation of a sustainable development policy in the field of road construction. The utilised waste materials include 50% (m/m) reclaimed asphalt pavement (RAP) from damaged asphalt layers and 30% (m/m) recycled aggregate (RA) sourced from the substructure. In order to assess the possibility of using a significant amount of waste materials in the composition of the mineral–cement–emulsion (MCE) mixture, it is necessary to optimise the MCE mix. Optimisation was carried out with respect to the quantity and type of binding agents, such as Portland cement (CEM), bitumen emulsion (EMU), and redispersible polymer powder (RPP). The examination of the impact of the binding agents on the physico-mechanical characteristics of the MCE blend was performed using a Box–Behnken trivalent fractional design. This method has not been used before to optimise MCE mixture composition. This is a novelty in predicting MCE mixture properties. Examinations of the physical properties, mechanical properties, resistance to the effects of climatic factors, and stiffness modulus were conducted on Marshall samples prepared in laboratory settings. Mathematical models determining the variability of the attributes under analysis in correlation with the quantity of the binding agents were determined for the properties under investigation. The MCE mixture composition was optimised through the acquired mathematical models describing the physico-mechanical characteristics, resistance to climatic factors, and rigidity modulus. The optimisation was carried out through the generalised utility function UIII. The optimisation resulted in indicating the proportional percentages of the binders, enabling the assurance of the required properties of the cold recycled mix while utilising the maximum quantity of waste materials.

A Guideline for Cross-Sector Coupling of Carbon Capture Technologies

Many governments around the world have taken action to utilise carbon capture (CC) technologies to reduce CO2 emissions. This technology is particularly important to reduce unavoidable emissions from industries like cement plants, oil refineries, etc. The available literature in the public domain explores this theme from two distinct perspectives. The first category of papers focuses only on modelling the CC plants by investigating the details of the processes to separate CO2 from other gas components without considering the industrial applications and synergies between sectors. On the other hand, the second category investigates the required infrastructure that must be put in place to allow a suitable integration without considering the specific particularities of each carbon capture technology. This review gives a comprehensive guideline for the implementation of CC technologies for any given application while also considering the coupling between different energy sectors such as heating, power generation, etc. It also identifies the research gaps within this field, based on the existing literature. Moreover, it delves into various aspects and characteristics of these technologies, while comparing their energy penalties with the minimum work required for CO2 separation. Additionally, this review investigates the main industrial sectors with CC potential, the necessary transportation infrastructure from the point sources to the end users, and the needs and characteristics of storage facilities, as well as the utilisation of CO2 as a feedstock. Finally, an overview of the computation tools for CC processes and guidelines for their utilisation is given. The guidelines presented in this paper are the first attempt to provide a comprehensive overview of the technologies, and their requirements, needed to achieve the cross-sector coupling of CC plants for a wide range of applications. It is strongly believed that these guidelines will benefit all stakeholders in the value chain while enabling an accelerated deployment of these technologies.

Performance Analysis of Cement Plant Waste‐Heat Recovery for Power Generation Based on Partial Evaporating Cycle with Ejector

In the cement industry, much waste heat is released into the environment. The organic Rankine cycle is widely utilized to harness waste heat for power generation. However, significant energy is lost in the heat recovery process due to the finite temperature difference between the heat source and working fluid, resulting in low power output andefficiency. To enhance the heat recovery from the cement flue gas and increase power output and overall efficiency, a novel partial evaporating cycle with ejector is proposed and investigated in this study. Pinch point analysis is performed to characterize the heat recovery process in the evaporator. The effects of the evaporating temperature, outlet quality of the evaporator, and exit pressure of the primary expander on system performance are also investigated. Results show that partially evaporating the fluid improves heat matching and reduces the irreversibilities in the evaporator by up to 18.1% when the outlet quality of the fluid is 0.33. Maximum net power of 803.15 kW can be generated with an evaporating temperature of , outlet quality of 0.33, and expander exit pressure of 1054.9 kPa. Additionally, the inclusion of the ejector increases the net power produced by up to 76.07 kW.

Heavy metal dynamics in riverine mangrove systems: A case study on content, migration, and enrichment in surface sediments, pore water, and plants in Zhanjiang, China

Mangroves serve a crucial role as metal accumulators in tropical and subtropical marine ecosystems, particularly in riverine mangroves, which frequently interact with terrestrial sources. In this study, we focused on the Gaoqiao and Jiuzhou Rivers within the Zhanjiang mangrove forest in Guangdong, China, and collected leaves and surface sediments from the dominant mangrove plant, Aegiceras corniculatum, near the riverbanks. We focused on seven heavy metals (Cr, Cu, Zn, As, Cd, Pb, and Hg) in mangrove leaves, surface sediments, and pore water due to their environmental significance and frequent occurrence in mangrove ecosystems. We employed multivariate statistical methods and pollution indicators to assess the potential sources and risk levels of heavy metals in these sediments. Our results reveal that the concentrations of the seven heavy metals in the sediments of the Gaoqiao and Jiuzhou Rivers varied significantly, ranging from 0.03 mg/kg to 100.00 mg/kg. Cd posed the highest ecological risk, followed by Hg and As. The comprehensive potential ecological risk in the Gaoqiao River was lower than that in the Jiuzhou River, likely due to the distribution of industrial enterprises (such as printing and cement plants) in the upper reaches of the Jiuzhou River. Additionally, the heavy metal content in the leaves and pore water of A. corniculatum ranged from 0.01 to 51.58 mg/kg and 0.001 to 133.70 μg/L, respectively. There was a significant correlation between the heavy metal concentrations in the leaves and the pore water of A. corniculatum. Notably, the leaves of A. corniculatum exhibited a remarkable Hg-enrichment capability, highlighting its potential as a mercury accumulator. Most heavy metals in A. corniculatum leaves, pore water, and sediment were concentrated in the middle and upper reaches of the river, primarily due to anthropogenic terrestrial inputs from residential production activities upstream. Consequently, heavy metal pollution in riverine mangroves is primarily associated with human activities such as aquaculture, agricultural planting, and industrial production.

Impact of treated sewage water on early strength development of calcium sulfoaluminate cement paste: A comparative study

This study investigates the use of treated sewage water (TSW) as a substitute for fresh tap water (FTW) in concrete production using calcium sulfoaluminate (CSA) cement. The research addresses concerns about freshwater scarcity and emphasizes CSA cement's rapid setting properties, crucial for emergency constructions like military airfield recovery. The focus is on the early-age properties of CSA paste mixed with TSW, with assessments conducted at 4 hours, 1 day, and 3 days post-mixing. Key parameters, including slump, setting times, and hardened characteristics, were evaluated. TSW contained significant metal concentrations and a high pH, with total dissolved solids exceeding FTW by 67%, yet all parameters remained within acceptable limits. Analytical techniques identified ettringite (AFt) as a primary hydration product, while ye'elimite (C4A3Š) was present as a component of the unhydrated clinker in the CSA cement. Simulations showed improved stability in the TSW-CSA interface compared to FTW, although early hydration was slower, likely due to delayed C4A3Š hydration and increased AFt formation. Initially, CSA/TSW pastes presented a refined microstructure, which altered by 3 days. Despite a 14% faster final setting time, compressive strength was 21% lower at 4 hours. These findings highlight TSW's potential as a sustainable alternative in CSA cement mixing, necessitating further research for long-term performance evaluation.

Comparative Life Cycle Assessments of Laboratory and Pilot-Scale Mechanochemical Processes for Producing Carbonated Mineral Products as Cement Substitutes.

The use of carbonated mineral products in cement production reduces carbon emissions and enhances durability. This study evaluated the environmental sustainability of using mineral carbonated biomass fly ash (BFA) as a partial cement replacement in European cement production. Laboratory-scale and simulated large-scale scenarios were analysed. Incorporating 20% mineral carbonated BFA showed potential for a 33% reduction in the annual Global Warming Potential (GWP) of cement products. Energy consumption factors, such as ball milling and mineral carbonation processes, were evaluated using a machine learning model and comminution flow sheet model simulations. The machine learning model predicted CO2 absorption and energy requirements for mineral carbonation, showing greater efficiency in large-scale scenarios. Life cycle assessments consistently revealed GWP reductions for OPC-BFA mixtures, with additional emissions reductions when incorporating flow sheet modelling and machine learning data. However, the study's limitations include simplified CO2 flue gas treatment, use of the mean EU electricity mix, exclusion of transportation impacts, and reliance on simulation data. Additionally, the cement mix exhibited reduced compressive strength. This study highlights the potential of mineral carbonated BFA to reduce cement production's environmental impact while emphasising the need for balanced optimisation between sustainability and material performance.

Understanding the time-dependent rheological behavior of seawater mixed cement paste with fly ash

Due to the relative scarcity of freshwater resources in coastal regions, the use of seawater in concrete construction has great potential due to its benefits in cost and resource. To further advance the application of seawater concrete, a deeper understanding of its rheological properties is essential. This study investigates the effects of fly ash on the time-dependent rheological behavior of seawater cementitious paste, such as yield stress, plastic viscosity, and structural build-up rate. The underlying mechanisms are analyzed using the theories of water film thickness (WFT), ion concentration, and hydration heat. The research findings confirm that the rheological parameters of seawater paste are generally higher than those of deionized water paste, regardless of the cementitious compositions. As fly ash content increases, the plastic viscosity of seawater paste increase, while the fluidity and dynamic yield stress decreases. Further analysis reveals that the decrease in the yield stress with fly ash content is well related to the increase in the WFT, but it cannot sufficiently explain the change of yield stress over time. Instead, the amount of hydration products in seawater paste shows a linear increasing relationship with the dynamic yield stress at 65 min. By contrast, the plastic viscosity can be related to the ion concentration in the interstitial solution, wherein an increase in the concentration of Ca2+ corresponds to an increase in the plastic viscosity. Moreover, the rheological parameters increase over time, with the growth rates between 5 and 35 minutes being higher than those between 35 and 65 minutes, possibly due to the rapid early hydration of the binder materials. This study offers a fundamental theoretical support for the use of seawater in various concrete applications.

Applications of Carbon Capture Technologies in Steel and Cement Industries

As problems such as the increase in extreme weather, rising sea levels, and social inequality continue to sharpen with the intensifying climate change, changes are demanded. The cement and iron and steel industries are among the major spheres responsible for the rising global temperature. Carbon reduction methods cannot fully solve the problem and help these industries reach carbon-neutral emissions. Therefore, carbon capture (CC) technology is urgently needed. This article introduces the application of pre-combustion carbon capture (PreCCC), post-combustion carbon capture (PostCCC), and oxyfuel combustion carbon capture in the cement industry and the iron and steel industry. Research has shown that oxyfuel combustion is one of the most assuring pathways to reach carbon neutrality in cement plants since problems of temperature management can be solved by recycling part of the fuel gases, and its cost is relatively lower than the other methods. However, PostCCC is a better solution in the iron and steel industries. Although technological innovations in physical absorption and chemical absorption are still needed, PostCCC can mitigate a large portion of steel plants carbon footprint. Carbon capture intensity can be increased with further technological development in combining PostCCC and oxygen-rich combustion. The combination of different pathways may be a novel hypothesis, but it has a great possibility of alleviating the carbon emission of the industrial sector.

Analysis of the Vertical Dynamic Response of SDCM Piles in Coastal Areas

The stiffened deep cement mixing (SDCM) pile, as a new type of rigid–flexible composite pile, significantly enhances the vertical bearing capacity of traditional precast piles, thus holding broad application prospects in the substructure construction of nearshore bridges and marine energy structures. This paper investigates the vertical dynamic response of SDCM piles through theoretical derivation and parameter analysis. Firstly, based on elastic dynamics theory and the three-phase porous media model, vertical vibration control equations for both SDCM piles and fractional-order viscoelastic unsaturated soils are established. Secondly, theoretical derivations yield exact analytical solutions for the surrounding dynamic impedance, top dynamic stiffness, and dynamic damping of the SDCM pile. Finally, through numerical examples and parameter studies, the impact mechanisms of physical parameters in the SDCM pile–unsaturated soil dynamic coupling system on the top dynamic stiffness and dynamic damping of the SDCM pile are analyzed. The research results presented in this paper indicate that reducing the radius of the rigid core pile while increasing the thickness of the exterior pile has a positive effect on enhancing its vibration resistance. Additionally, increasing the length of SDCM piles contributes to improved vibration performance. However, an increase in the elastic modulus of the cement–soil exterior pile is detrimental to the vibration resistance of the rigid composite pile. On the other hand, an increase in the elastic modulus of the concrete core pile only enhances its ability to resist vibration under low-frequency load excitation. Furthermore, enlarging the soil saturation, decreasing the intrinsic permeability, and enlarging the soil relaxation shear modulus have a significant positive impact on improving the vibration resistance of SDCM piles. In contrast, changes in porosity have a negligible effect on the ability to resist vertical vibrations of SDCM piles.

Health risk assessment of toxic metals and DNA damage in somatic and germ cells by soil and groundwater of a major cement factory in Nigeria.

The waste generated from cement manufacturing is an important source of heavy metal contamination of groundwater and soil. This study investigated the concentration of toxic metals in the soil of a major cement factory and nearby groundwater. Ecological and carcinogenic risks of the metals were calculated. Potential reproductive toxicity and genotoxic effects of the samples were assessed in sex and somatic cells of male mice using sperm abnormalities and bone marrow micronucleus (MN) assays, respectively. Also, the serum ALP, ALT, AST, Total Testosterone (TT), Luteinizing Hormone (LH), and Follicle Stimulating Hormone (FSH); and liver SOD and CAT activities were measured in the treated mice. Cr, Cu, Ni, Zn, Mn, Cd, and Pb levels in the soil and groundwater exceeded the allowable maximum standard. Ingestion and dermal contact were the most probable routes of human exposure with children having about three times higher probability of exposure to the metals than the adults. Ni, Pb, and Cr presented carcinogenic risks in children and adults. In the MN result, nuclear abnormalities in the studied mice especially micronucleated polychromatic erythrocytes increased significantly (p < 0.05). Compared to the negative control, the ratio of PCE/NCE showed the cytotoxicity of the two samples. Data further showed a significant increase in the serum ALP, AST, and ALT while the liver CAT and SOD activities concomitantly decreased in the exposed mice. Sperm morphology result showed that the samples contained constituents capable of inducing reproductive toxicity in exposed organisms, with alterations to the concentrations of TT, LH, and FSH. Toxic metal constituents of the samples were believed to induce these reported reproductive toxicity and genotoxic effect. These results showed the environmental pollution caused by cement factory and the potential effects the pollutants might have on exposed eukaryotic organisms.

Impact of Occupational Cement Dust Exposure on Hematological Health Parameters: A Cross-Sectional Study.

Introduction Contact with the dust of cement consisting of toxic components brings about inflammatory damage (often irreversible) to the body of a human being. The circulatory system exhibits sensitivity to inflammatory changes in the body, and one of the earliest changes may be observed in the blood parameters like mean corpuscular hemoglobin (MCH) and mean corpuscular hemoglobin concentration (MCHC). MCHC and MCH are possibly easily accessible and affordable parameters that can detect harmful changes in the body before any irreversible damage occurs. Objectives This research aimed to seek the changes in MCHC and MCH upon occupational contact with the toxic dust of cement. Methods The execution of this research was done in the Department of Physiology, Dhaka Medical College, Bangladesh, and a cement plant in Munshiganj, Bangladesh. This research was carried out between September 2017 and August 2018. Individuals (20 to 50 years old, 92 male adults) participated and were grouped into the group with occupational cement dust impact (46 subjects) and the group without occupational dust of cement impact (46 subjects). Data was collected in a pre-designed questionnaire. An independent sample t-test was conducted to analyze statistical and demographic data like body mass index and blood pressure. A multivariate regression model was applied to note the impact of cement dust on the group working in this dusty environment. Again, a multivariate regression model was employed to observe whether the duration of exposure to this dust affected MCHC and MCH. The significance level was demarcated at p < 0.05 Stata-15 (StataCorp LLC, College Station, TX, US) for statistical analysis, and GraphPad Prism v8.3.2 (Insight Venture Management, LLC, New York, NY, US) was employed to present the data graphically when required. Results There was a reduction in MCHC by 0.58 g/dL and MCH levels by 0.68 pg in the cement dust-exposed subjects when compared to controls, but not significant (95% CI: -0.93, 2.10;p = 0.448 and 95% CI: -0.37, 1.73;p= 0.203, respectively). However, MCHC was reduced significantly by 0.51 g/dL (p = 0.011) with the duration of exposure to the dust. Conclusion The study showed that MCHC was significantly reduced with the duration of exposure to cement dust in cement plant workers. Such alterations may hamper heme synthesis, hemolysis, and inflammatory changes in the body.

Deep caries and pulp exposures management preferences in permanent teeth: A survey amongst Spanish dentists.

To assess Spanish dentists' management preferences for deep caries removal and exposed pulps in permanent teeth. A web-based open and anonymous survey was distributed by social media and a specific website for this project amongst dentists practicing in Spain. The questionnaire comprised 40 questions, divided into five sections: (1) demographic data and professional activity; (2) carious tissue removal; (3) decision-making regarding pulp exposure; (4) direct pulp capping and (5) pulpotomy procedures in permanent teeth. Results were descriptively analysed. Logistic regression (95% CI) analyses and X2 tests were carried out. A total of 538 responses were received. Half the respondents (53.7%) preferred to perform complete caries excavation for shallow and moderate carious dentin lesions, and selective excavation to firm dentin for deep lesions (57.8%). Selective removal to soft dentin and stepwise removal were much less indicated (15.4% and 10.9%, respectively). Exposed pulps in asymptomatic teeth were treated by direct pulp capping (over 80%), decreasing in the presence of reversible pulpitis symptoms (57.1%). If irreversible pulpitis was diagnosed, a pulpectomy would be performed by 53.5% and 89.9% of the respondents in, respectively, immature and mature teeth. Pulpotomy was performed routinely only by 26.4% of the clinicians. Patients' attitudes and priorities were the most relevant criteria when performing direct pulp capping and pulpotomy, together with the history of pain and the presence of bleeding. Regarding the clinical procedure, dry cotton was preferred to obtain haemostasis and Biodentine was the material of election. Caries removal preferences and management of pulp exposure by dentists practicing in Spain deviated from vital pulp treatment guidelines, mainly regarding indications and case selection. Pulp exposure was managed by direct pulp capping in asymptomatic cases, whilst immature permanent molars favoured the indication of pulpotomy when pulpitis was diagnosed. Most clinicians used hydraulic calcium silicate cement, specifically Biodentine, to perform vital pulp treatments. Postgraduate formation and continuing education in caries lesions management and vital pulp treatments were consistently related to more conservative and updated decisions.

Root-filling materials for endodontic surgery: biological and clinical aspects

The placement of root filling materials aims to prevent the occurrence of post-treatment apical periodontitis following completion of endodontic treatment. Materials should possess properties that will not permit bacterial invasion and infection, namely excellent sealing ability and/or antibacterial properties. In root-end filling procedures or repair of root perforations, the root filling materials are placed in a particularly challenging clinical environment, as they interface with a relatively large area with the periradicular tissues. The biological properties of these materials are therefore of significant importance. The current review discusses the most widely used materials for endodontic surgery (i.e., root-end filling and perforation repair), with particular focus on their biological characteristics, namely antibacterial properties and interactions with host tissue cells, together with clinical studies. Properties of amalgam, glass ionomer cements (GICs), resin systems, zinc oxide eugenol-based cements and hydraulic calcium silicate cements (HCSCs), together with representative and well-researched commercial materials in the context of their use in endodontic surgery are presented. While the use of HCSCs seems to offer several biological advantages, together with addressing issues with the initial formulation in the most recent versions, materials with different chemical compositions, such as zinc oxide eugenol-based cements, are still in use and appear to provide similar clinical success rates to HCSCs. Thus, the significance of the currently available materials on clinical outcomes remains unclear.