Introduction: Indirect Pulp Capping (IPC) is defined as a procedure wherein a small amount of carious dentin is retained in deep areas of the cavity to avoid exposure of pulp, followed by placement of a suitable medicament and restorative material that seals off the carious dentin and encourages pulp recovery. Calcium hydroxide has been the gold standard for pulp capping material due to its exceptional biocompatibility, antibacterial properties, and ability to encourage the formation of reparative dentin. Fish Bone (FB) powder is a naturally occurring substance that has shown promise as a pulp capping material. It contains a lot of calcium, phosphates, and other bioactive substances that could help with dentinogenesis and repair. To ascertain whether it can be a suitable substitute for or addition to calcium hydroxide, its antimicrobial activity and sealing capacity must be thoroughly assessed. Need of the study: The current study can demonstrate the antimicrobial effectiveness and sealing ability of FB paste as a pulp capping material. Aim: To evaluate and compare the anti-microbial efficacy and sealing ability of FB paste with calcium hydroxide paste as pulp capping materials through an in-vitro study. Materials and Methods: An in-vitro study will be conducted in Department of Paediatric and Preventive Dentistry at Sharad Pawar Dental College, Wardha, Maharashtra, India, from May 2025 to December 2025, in which FB paste and calcium hydroxide paste will be prepared to evaluate and compare the anti-microbial efficacy and sealing ability for an in-vitro investigation in the Department of Paediatric and Preventive Dentistry at Sharad Pawar Dental College, Wardha, Maharashtra, India. The agar diffusion method will be used to evaluate the antibacterial efficacy of calcium hydroxide paste and FB paste against Enterococcus faecalis. After being cultivated in brain-heart infusion broth for the entire night, the E. faecalis stock culture will be injected onto Muller-Hinton agar plates. A copper puncher will be used to create wells on the plates that are 4 mm in diameter and 4 mm deep. The wells will then be promptly filled with freshly created, specially designed test materials. After being incubated at 37°C for 24 and 72 hours, the agar plates will be evaluated. The diameter of the zone of inhibition will be measured in millimetres after incubation. The dye penetration method will be used to evaluate the sealing ability of calcium hydroxide paste and FB paste. After preparing a Class I cavity, pulp capping material consisting of calcium hydroxide and powdered FBs will be inserted into the cavity. All samples will undergo 500 thermocycling cycles with 60-second dwell intervals to replicate dental conditions, and each tooth will receive two coats of nail polish with a 1 mm margin around the restoration border. Following a 24-hour incubation period at room temperature in 5% methylene blue dye, the samples will be rinsed under running water and then sectioned mesiodistally using a diamond disk with water cooling. To assess the material's capacity to seal, the degree of dye penetration will be evaluated. The Chi-square test, student paired and unpaired t-test, One-way Analysis of Variance (ANOVA), and Tukey test will all be used in the statistical analysis.

Introduction: Preserving the health and structure of primary teeth is crucial for a child’s growth and development. Premature extraction of primary teeth can lead to unfavourable changes in the eruption pattern and alignment of permanent teeth. To ensure the success of endodontic therapy in primary teeth, it is essential to use a biocompatible obturating material with effective antimicrobial properties. An ideal root canal filling material for primary teeth should not harm the periapical tissues, should promote the normal development of the permanent successor tooth and should undergo resorption simultaneously with root resorption. Additionally, it should be easy to place, adhere to the root canal walls, resorb if extruded beyond the apex, appear radiopaque on radiographs and not cause tooth discolouration. Zinc oxide Eugenol (ZnOE), iodoform-based pastes and calcium hydroxide are commonly used obturating materials for primary teeth. However, ZnOE has several disadvantages, including slow resorption, potential tissue irritation, bone and cementum necrosis and interference with the eruption of permanent teeth. Theobromine is a crystalline, water-insoluble alkaloid found in cacao plants. It has been shown to strengthen tooth enamel and exhibit antibacterial activity against microorganisms such as Lactobacillus acidophilus and Enterococcus faecalis. Need of the study: There is a need to identify root canal filling materials suitable for primary teeth that combine effective antimicrobial activity with biocompatibility and appropriate resorbability. Existing materials, such as zinc oxide eugenol, possess limitations that may compromise treatment outcomes. Therefore, investigating formulations enhanced with theobromine may represent a potential advancement in paediatric endodontics. Aim: To assess and compare the antimicrobial effectiveness of root canal filling materials, including zinc oxide eugenol and calcium hydroxide, combined with theobromine in primary teeth. Materials and Methods: An in-vitro study will be conducted at the Department of Paediatric and Preventive Dentistry at Sharad Pawar Dental College and Hospital, in collaboration with the Department of Microbiology, Jawaharlal Nehru Medical College, Datta Meghe Institute of Higher Education and Research (DMIHER), Sawangi, Wardha, Maharashtra, India, involving 25 patients aged 4-8 years. Microbial samples will be collected from infected primary molar teeth. The antimicrobial efficacy of four different root canal filling materials—zinc oxide mixed with theobromine, zinc oxide eugenol, calcium hydroxide mixed with theobromine and calcium hydroxide mixed with saline—will be evaluated. Vaseline will serve as the negative control. The mean zone of inhibition will be considered the primary outcome measure. Data will be tested for normality using the Shapiro– Wilk test. If the data are normally distributed, one-way Analysis of Variance (ANOVA) followed by Tukey’s post hoc test will be applied. If the data are not normally distributed, the Kruskal– Wallis test followed by the Mann-Whitney U test with Bonferroni correction will be used. A p-value of <0.05 will be considered statistically significant.

The objectives of this study were to estimate and compare the 1-year clinical success rates of triple antibiotic paste (TAP), double antibiotic paste (DAP), calcium hydroxide (CH) within regenerative endodontic procedures (REPs) on permanent necrotic immature teeth. Trials investigating REP success were searched through MEDLINE, Scopus, Embase, Web of Science, GOOGLE Scholar (last update December 2025). Primary study quality was evaluated through the revised Cochrane Risk of Bias tool for Randomised Trials (RoB2). Pooled success rates with 95% confidence intervals (95% CIs) were assessed. Heterogeneity was investigated with the Cochran's Q and quantified with I2: The random-effects model was preferred to the fixed-effect model for I2 > 50%. Sensitivity (study quality, publication bias, study inclusion) and subgroup (scaffold type, world Region) analyses were made. The differences in pooled success rates between protocols were assessed and were evaluated using an equivalence range of -2.5%/+2.5%. The GRADE system was employed to evaluate the Quality of Evidence of the pooled success rates. Twenty-four studies of average quality were included involving 544, 64, 183 patients, for TAP, DAP, CH, respectively. The pooled success rates (tooth survival after 1 year with periapical healing, absence of signs and symptoms of pathology) were TAP 96.7% (95% CI, 94.8%-98.0%), DAP 84.2% (95% CI, 73.2%-92.0%), CH 97.4% (95% CI, 93.9%-99.1%). The pooled differences in success rates were TAP-DAP 12.5% (95% CI, 2.8%-22.1%, TAP superiority demonstrated), TAP-CH -0.7% (95% CI, -0.9%-2.5%, TAP/CH equivalence demonstrated), CH-DAP 13.2% (95% CI, 3.3%-23.0%, CH superiority demonstrated). Secondary analyses corroborated these results, although the overall statistical test power was low due to small sample sizes. The GRADE quality of evidence was high for TAP and CH, and low for DAP, due to substantial imprecision attributed to the small number of studies with small sample sizes. The lack of direct comparisons between protocols and of a common comparator did not allow for more robust analyses. Nevertheless, the use of TAP and CH as intracanal medicament within REPs resulted equivalent in eradicating the infection and promoting periapical healing in permanent necrotic immature teeth at 1-year follow up, and these protocols resulted superior over DAP. PROSPERO registration number: CRD42023484189.

Molecular analysis of intracanal microbial reduction to compare the effectiveness of glycyrrhizin and calcium hydroxide as intracanal medications: a randomised controlled trial.

The present case report aimed to present an immunohistological analysis of newly formed intracanal tissues in a traumatised immature permanent incisor with pulp necrosis and apical periodontitis following RET. A 7-year-old girl sustained a combined traumatic dental injury, an uncomplicated crown fracture and lateral luxation, affecting an immature maxillary central incisor. The tooth subsequently developed pulpal necrosis and apical periodontitis and was treated with RET using calcium hydroxide as an intracanal medicament. A blood clot served as the scaffold, followed by placement of calcium silicate cement (Biodentine®) and a definitive resin composite restoration. During follow-up, the tooth developed ankylosis with progressive infraocclusion. At 13years of age, the tooth was extracted, and prosthetic rehabilitation was completed using a resin-bonded Rochette bridge. Histological and immunohistological analyses revealed a heterogeneous mixture of mineralised and connective tissues within the root canal space. The tissues demonstrated infiltration of fibroblast-like cells, resorptive cells, blood vessels and nerve fibres. Numerous fibrous cystic structures containing cholesterol crystals were identified in the middle third of the root canal. The newly formed intracanal tissues demonstrated limited similarity to intact odontogenic tissues. Both inflammatory root resorption and ankylosis-related replacement resorption, likely associated with the initial luxation injury, were observed. The presence of cholesterol crystal deposits represents a novel finding that may provide new insights into the biological processes occurring after RET. As cellular events following RET cannot be fully controlled clinically, the risk of unfavourable outcomes should be considered carefully, particularly in cases involving luxation injuries.

Under dual challenges of global infrastructure expansion and industrial solid waste management, alkali-activated polymers (AAP), as industrial solid-waste-based low-carbon cementitious materials, exhibit immense potential in grouting engineering applications. This review synthesizes current research progress through three critical dimensions: reaction mechanisms, performance characteristics, and grouting applications (grouting for reinforcement and water-blocking). The reaction mechanism universally comprises three stages: dissolution, depolymerization, and polycondensation. Key performance determinants include precursor composition (e.g., slag, fly ash, metakaolin) and alkaline activator properties (type, modulus, concentration). The multifunctional advantages of AAP are fundamentally governed by their microstructural evolution. Specifically, the rapid formation of highly cross-linked C-(A)-S-H and N-A-S-H gels directly contributes to rapid setting and high early strength development, with high-calcium precursors such as slag exhibiting faster strength gain than low-calcium systems, such as fly ash and metakaolin. Furthermore, the absence of vulnerable calcium hydroxide phases, combined with a densified, low-porosity aluminosilicate network, provides superior thermal stability, corrosion resistance, frost durability, and low permeability. Nevertheless, pronounced autogenous shrinkage and drying shrinkage, driven by mesopore moisture loss and the highly viscoelastic solid skeleton, remain primary constraints for field implementation. In grouting reinforcement, AAP can effectively enhance the strength and structural integrity of weak soils, such as soft clay, loess, and sulfate-rich saline soils. For grouting water-blocking, particularly in sodium-silicate-based binary systems, AAP achieves rapid gelation, superior washout resistance, and high anti-seepage pressure, proving optimal for groundwater inflow control. Future research must prioritize (i) standardized mix design protocols for performance consistency, (ii) advanced shrinkage mitigation strategies, (iii) systematic durability assessment under coupled environmental stressors (e.g., wet-dry cycling, chemical attack, thermal fatigue), and (iv) cross-disciplinary collaboration for industrial-scale validation.

This invitro study investigated the antibiofilm efficacy of calcium silicate-based, Simvastatin, Levofloxacin and calcium hydroxide intracanal medicaments against mature Enterococcus faecalis biofilm. Ninety dentine specimens were inoculated with Enterococcus faecalis biofilm for three weeks and divided into five groups (n = 18): (1) calcium silicate-based; (2) Simvastatin; (3) Levofloxacin; (4) calcium hydroxide (CH); (5) positive control, no medicament. After two weeks of intracanal medicament application, live/dead bacterial cells were assessed using confocal laser scanning microscopy. The results revealed a statistically significant difference in the percentage of dead bacteria of the four tested groups compared to the positive control group (H = 30.45, p < 0.001). The calcium silicate-based group recorded the highest median (IQR) percentage of dead bacteria at 56.33 (10.03), followed by Simvastatin 44.88 (7.30), CH 41.70 (12.53), Levofloxacin 35.99 (3.78), and the positive control group 3.61 (1.01). These findings suggest that these intracanal medicaments demonstrate promising antibiofilm activity, with further investigations needed.

The endodontic management of immature permanent teeth with open apices that subsequently become necrotic presents a significant clinical and research challenge. Such cases are problematic due to the difficulty in achieving effective disinfection, proper apical closure, and long-term sealing of the root canal system. Over the years, various treatment approaches have been introduced to address this issue and promote apical closure and repair. These include apexification with calcium hydroxide, the use of Mineral Trioxide Aggregate (MTA), and, more recently, the application of advanced bioceramic materials, which have shown promising outcomes in root-end modification. These modern bioceramics include MTA, Biodentine®, which is used in successful root-end procedures due to the benefits of biocompatibility, sealing ability, and bioactivity. Issues include the long setting times, sensitivity towards handling, and high costs. This paper also reviews the more traditional apexification techniques and newer approaches like pulp revascularisation and regeneration against modern bioceramic materials. While these materials have had encouraging results, more clinical trials are needed to evaluate their long-term effectiveness.

A critical review on functionalized biochar from solid waste: Advancing sustainable construction and CO2 capture.

Injury to the mineralized tissues that protect the dental pulp can lead to pulp exposure and inflammation, necessitating the use of biologically active materials capable of preserving pulp vitality. While current biomaterials such as mineral trioxide aggregate (MTA) are widely used in vital pulp therapy (VPT), their high cost, challenging handling, and lack of structural flexibility highlight the need for alternatives. Here, we introduce a multifunctional bilayer scaffold composed of a polycaprolactone (PCL) film and a PCL/poly(ethylene oxide) (PCL/PEO) blend loaded with calcium hydroxide (CH), designed to provide both cytoprotection and mineralized tissue regeneration. The scaffold features a compact PCL layer, acting as a barrier to protect the pulp from external cytotoxic agents, and a CH-loaded fibrillar PCL/PEO electrospun layer, aimed at promoting odontoblastic differentiation through sustained calcium ion release. The bilayer structure demonstrated mechanical stability and a degradation profile suitable for clinical application. The release mechanism relies on gradual fiber degradation and CH dissolution. In vitro, the fibrillar layer enhanced calcium ion release, supported dental pulp stem cell adhesion and viability, and stimulated mineralized matrix formation. The compact layer preserved cell viability even in the presence of glass ionomer cement. In vivo, the bilayer scaffold elicited a comparable inflammatory response and expression of dentinogenesis and angiogenesis markers relative to MTA, although it did not attain the same level of mineralized tissue formation. Overall, our results indicate that this multifunctional bilayer scaffold offers a cost-effective, dual-purpose alternative to current materials, with potential for further optimization of its tissue regeneration capabilities prior to clinical implementation.

Regenerating mineralized tissues under degenerative inflammatory stimuli is challenging, as elevated pro-inflammatory mediators impair the reparative capacity of resident cells. This study developed a chitosan-based scaffold functionalized with calcium hydroxide and simvastatin to modulate inflammation and enhance bone regeneration in inflammatory conditions. Scaffolds were fabricated from 2% chitosan, with or without Ca(OH)₂, and incubated in 1 μM simvastatin, generating four formulations: CH, CH-Ca, CH-SV, and CH-Ca-SV. In vitro, SAOS-2 cells were preconditioned in serum-free medium with or without TNF-α (100 ng/mL) for three days to simulate a degenerative inflammatory microenvironment. Cell metabolic activity, expression of inflammatory genes, alkaline phosphatase activity, mineralized matrix deposition, and osteogenic gene expression were assessed. In vivo, critical-size calvarial defects were created in Wistar rats, with or without TNF-α-induced osteolytic lesions, and filled with blood clot (control), CH-Ca, or CH-Ca-SV. After 14 and 30 days, samples were analyzed by micro-computed tomography, histology, and immunohistochemistry (IL-1β, TNF-α). In vitro, CH-SV and CH-Ca-SV extracts significantly increased cell metabolic activity, enhanced osteogenic differentiation, and downregulated TNF-α, MMP9, and IL-1β under inflammatory challenge. In vivo, CH-Ca-SV scaffolds promoted greater bone formation, reduced inflammatory infiltrate, and improved scaffold integrity compared to CH-Ca. Immunohistochemistry confirmed higher cytokine expression in control defects. Overall, simvastatin-loaded chitosan-calcium scaffolds effectively modulate inflammation and enhance bone regeneration even in a pro-inflammatory environment, supporting their potential for treating inflammatory bone defects.

This study unravels the intermolecular mechanistic degradation of palm oil mill effluent (POME) in sulfate removal, utilizing a distinctive coagulant derived from naturally abundant limestone (CaCO3), which was activated into calcium hydroxide [Ca(OH)2] through calcination and exothermic reactions. Sulfate was reduced from POME by 88.76% with the optimal conditions (pH 5, 200 g/L Ca(OH)2 dosage, and 135 min settling time) with strong correlation (r = 0.8237) and statistically significant (p = 0.0064) of Pearson's correlation. Scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDX) revealed an ideal morphology and elemental composition with reduction of 4.4753 m2/g surface area in Ca(OH)2 to slurry. Kinetic studies evaluated that sulfate removal at 4400 mg/L strongly followed the second-order model with a high coefficient of determination (R2 = 0.9883). Analysis using Fourier-transform infrared spectroscopy (FTIR) and gas chromatography-mass spectrometry (GC-MS) detected the formation of 2-isopropyl-5-methyl-1-heptanol (C11H24O). Overall, this study demonstrates the potential of Ca(OH)2 from CaCO3 as an efficient material for POME additional treatment, helping reduce VOCs and improve the value of industrial wastewater.

Tuning setting behavior, ion release, and pH stability of calcium hydroxide cement via carbonate-hydroxyapatite and ellagic acid

Synergistic regulation of calcium hydroxide and ARC microbial inoculant on rhizosphere microbiota and soil chemical properties during peanut middle growth stages in acidic red soils

Lime treatment is widely applied for stabilizing and conditioning municipal sewage sludge to improve handling and hygienic properties. It also offers the potential for carbon dioxide (CO2) sequestration through lime recarbonation. Thereby, atmospheric CO2 reacts with calcium hydroxide (Ca(OH)2) to form calcium carbonate (CaCO3), partly or fully offsetting process CO2 emissions generated during lime production. However, its extent and rate are largely unexplored. We investigated the spontaneous recarbonation of lime-treated sewage sludge using samples from two full-scale wastewater treatment plants (WWTPs). WWTP1 applies hydrated lime prior to dewatering, while WWTP2 adds quicklime after dewatering. Samples were incubated under controlled conditions for six months and analyzed using thermogravimetry-mass spectrometry (TGA-MS), X-ray diffraction (XRD), and bulk element determinations. Progressive transformation of Ca(OH)2 into CaCO3 confirmed spontaneous recarbonation. Within four months, WWTP1 samples reached near-complete carbonation with rates approaching 100% of the calcination-related process CO2 emissions. By contrast, WWTP2 samples exhibited lower rates of recarbonation, with a maximum of ∼94%, likely due to heterogeneous lime distribution, and encapsulation of unreacted lime along with differences in lime quality. These findings provide the first conclusive evidence for substantial spontaneous recarbonation of lime-treated sewage sludge under ambient conditions. They demonstrate that CO2 uptake is strongly influenced by lime type, dosing strategy, and sludge composition. This establishes a robust basis for integrating lime recarbonation into carbon accounting frameworks and for evaluating the long-term carbon sink potential of lime-treated sludge, while fuel-related emissions from lime production remain outside the scope of this study.

The production of Portland cement has a significant global impact. Consequently, research into clinker replacement materials and alternative low-CO2 cements is becoming increasingly important to minimize their carbon footprint. For this study, limestone and raw clay were sourced from various locations in Egypt. These materials were calcined in a kiln at temperatures of 950°C and 750°C for 2h, respectively. The primary goal of this study is to prepare and render mortars based on calcined clay with lime as a low-energy binder. The research primarily focuses on the mechanical and microstructural properties of lime-clay mortars and lime-clay render mortars, specifically hydrated lime (HL) and calcined clay (CCL). The mechanical and physical properties of these mortars were tested according to EN 196-1, using a mixing ratio of 1:3 (binder to sand) with total weight proportions of 450:1350. Water was added to achieve the necessary consistency and workability for this type of mortar, with an amount of approximately 302 ± 5g. The results suggest that the most recommended proportion for optimal mortar performance with the used binder (CCL-HL) is L40, mainly consisting of 60% CCL and 40% HL with a water-to-solid ratio of approximately 0.17. The compressive and flexural strengths for the CCL-HL mortar sample (L40) are 13.2MPa and 3.2MPa, respectively. Additionally, the preparation of render mortars using this binder (L40) demonstrates that the most cost-effective and environmentally friendly binder proportion is R35Y, which consists of 35% L40 and 2% Fe2O3 as a yellow pigment, with a water-to-solid ratio of approximately 0.30. The compressive and flexural strengths of the R35Y render mortar are 5.2 and 2.1MPa, respectively. The findings demonstrate that all prepared CCL-HL render mortars are suitable for rendering applications, meeting the requirements of EN998-1/2010 and offering a cost-effective, environmentally conscious solution for decorative and protective coatings, particularly in the preservation of historic structures.

Chemical burns are potentially blinding injuries and represent true ophthalmic emergencies that demand immediate evaluation and prompt initiation of treatment. Among these, alkali burns are more common than acid burns. Such injuries can cause widespread damage to the ocular surface epithelium, cornea, anterior segment structures, and limbal stem cells, often leading to permanent visual impairment in one or both eyes. We report a case of a 64-year-old female who developed diminution of vision following accidental chemical trauma with lime (calcium hydroxide). Clinical evaluation revealed deeply embedded corneal deposits without signs of acute infection or intraocular inflammation. She underwent surgical management involving superficial corneal scraping, thereby removing the necrotic tissue and suturing of a corneal patch graft. The surgery helped to restore ocular surface integrity, remove necrotic tissue, and promote healing, thereby reducing the risk of complications and preserving visual potential. Early surgical intervention and tailored postoperative care are essential for optimal outcomes in such cases.

The aim of the study. Improve the quality of dentine hypersensitivity treatment by modifying systems that seal dentine tubules (DT) with metal nanoparticles and their compounds. The study included 18 extracted teeth. The preparations «Gluftored» (GF) and «Dentin-Versiegelungsliquid» (DVL) were examined. For their modification, sol of TiO2 nanoparticles in distilled water and sol of Ti and TiC nanoparticles in ethyl alcohol were used. The particles had a size from 0.5 to 3 nm. In subgroups "A", the tooth was first wetted with hydrosol, and then immersed in alcohol; in subgroups "B", alcohol was added to the suspension of calcium hydroxide too. The results were evaluated using scanning electron microscopy. For each square millimeter we determined: the total number of DT and sealed DT, as well as the number of sealed DT with filling and fitting defects. When, the absolute and relative number of fully and qualitatively sealed DT were calculated. The differences between the groups were determined using the Kruskal-Walli's test. The largest percentage (80.98%) of completely sealed DT was observed in the experimental group, where both the dentine surface and the calcium hydroxide suspension in the GF were modified with hydrosol and alcohol. This index was 1.86 times higher (p<0.001) compared with the original GF, and 1.17 times higher (p=0.352) compared with the DVL preparation.

Abstract Bioactive endodontic sealers play a crucial role in restorative dentistry due to their ability to promote tissue repair and inhibit microbial proliferation. Given the high cost of commercial materials such as mineral trioxide aggregate (MTA), this study aimed to develop and characterize experimental bioactive endodontic cements composed of low-cost constituents—including fine Portland cement, ground metallurgical slag, and cellulose—while maintaining physicochemical and antimicrobial properties comparable to MTA (Angelus®). The materials were subjected to comprehensive characterization using X-ray diffraction (XRD), thermogravimetric analysis (TG/DTG), scanning electron microscopy (SEM), hydrogenionic potential (pH) analysis, inductively coupled plasma optical emission spectrometry (ICP-OES), and antimicrobial testing against Enterococcus faecalis using the agar diffusion method. Additionally, a complementary environmental assessment was performed to quantify potential CO₂ savings from clinker substitution with metallurgical slag, expressed as kg CO₂-eq per kilogram of cement. Statistical analyses were performed via ANOVA with Tukey’s post-hoc test. The experimental formulations revealed the presence of key bioactive phases, including calcium hydroxide, dicalcium and tricalcium silicates, tricalcium aluminate, and calcium carbonate. The materials exhibited a stable alkaline pH and effective antibacterial activity, confirming their biological potential. SEM imaging showed morphological differences between the experimental groups and commercial MTA, particularly regarding particle homogeneity. Nonetheless, overall physicochemical similarities were evident, especially for the slag-containing formulation (Group 2), which most closely mirrored the reference material. The environmental analysis indicated that slag incorporation led to a reduction of approximately 0.08 kg CO₂-eq per kilogram of cement (≈80 kg CO₂-eq per ton), highlighting the dual advantage of functional performance and environmental responsibility. These findings suggest the feasibility of producing alternative bioactive cements by reusing industrial by-products, offering a sustainable and economically viable option for endodontic applications without compromising clinical efficacy. Graphical Abstract

This study compared the mechanical properties of eggshell-derived hydroxyapatite (ESDHA), mineral trioxide aggregate (MTA), and calcium hydroxide (CH), and evaluated their cytotoxicity using human dental pulp stem cells (HDPSCs). Cement samples were prepared and incubated at 37°C under humid conditions. Cytotoxicity was assessed using extracts collected at different setting periods, followed by real-time cell analysis. Compressive strength was measured at multiple time points. Structural and chemical characterisation was performed using X-ray diffractometry, Raman spectroscopy, scanning electron microscopy, and energy-dispersive spectroscopy. ESDHA and MTA showed no cytotoxic effects, whereas CH exhibited initial cytotoxicity with a doubling time of 42.32 ± 1.69 h on day 1. MTA demonstrated the highest compressive strength (85.6 ± 3.2 MPa at 28 days), followed by ESDHA (18.9 ± 1.4 MPa), while CH had the lowest strength (5.1 ± 0.4 MPa). ESDHA appears to be a promising, cost-effective alternative with favourable cytocompatibility but requires mechanical improvement.