Calcium Hydroxide Research Articles

Intracanal medicaments and coronal sealing materials influence on root fracture resistance and coronal discoloration: An in vitro study

Abstract Introduction: Immature teeth are more susceptible to fracture, and intracanal medicaments and coronal filling materials used in regenerative endodontics affect their optic and mechanical properties. This study aimed to evaluate the fracture resistance and coronal discoloration of simulated immature teeth following the placement of several intracanal medicaments and coronal sealing materials. Materials and Methods: Eighty-eight premolars simulating immature teeth were divided into 11 groups (n = 8 each) according to the type of intracanal medicament (triple antibiotic paste [TAP]; double antibiotic pastes [DAP]; calcium hydroxide [Ca(OH)2]) and used coronal barrier materials (mineral trioxide aggregate [MTA] and calcium-enriched mixture [CEM]). A bonding agent was applied in half of the samples in the groups where antibiotic pastes were used (n = 8). After incubating for 3 weeks, the sample’s fracture resistance and color change were evaluated. Data analysis was conducted using multivariate and one-way analysis of variance, Tukey’s honestly significant difference post hoc, and the Kruskal–Wallis tests (α =0.05). Results: The color change after placing the medicaments was comparable among the groups. However, after 3 months, the color change in the TAP-CEM-No-Bonding group was higher than the control, Ca(OH)2-MTA, and DAP-MTA-No-Bonding groups (P < 0.05). The fracture resistance of the TAP-MTA-Bonding, DAP-CEM-Bonding, Ca(OH)2-MTA, and Ca(OH)2-CEM was lower than the control group (P < 0.05). Conclusion: Simultaneous use of DAP-MTA without a dentin bonding agent led to comparable color change and fracture resistance to the control group.

Performance of coal gangue concrete with fly ash and ground-granulated blast slag: Rheology, mechanical properties and microstructure

This paper aims to examine the effect of coal gangue aggregate (CGA), fly ash (FA), and ground-granulated blast slag (GGBS) on the rheological, mechanical and microstructure properties of concrete. The rheological properties, compressive strength, splitting tensile strength, flexural strength, and uniaxial tensile behaviour of coal gangue concrete (CGC) were determined, and the microstructure of the concrete mixtures were investigated by use of XRD and SEM analyses. The results revealed the action mechanism of CGA and mineral admixtures on the microstructure and macroscopic properties of CGC. FA first increased and then decreased the yield stress and plastic viscosity, while GGBS considerably increased the yield stress and plastic viscosity. Furthermore, a constitutive model was established for CGC containing FA and GGBS under compression. The proposed stress–strain model for CGC is accurate and can be used for nonlinear analysis of structures made of this type of concrete. Moreover, the addition of FA and GGBS consumes calcium hydroxide, but increases products such as hydrated calcium silicate aluminate. These findings elucidate the understanding and optimisation of CGA use in concrete production, while contributing to lowering carbon emissions.

Inorganic Compound and Cycloserine Composite Particles for Improved Stability

The aim of this study was to improve the chemical stability of cycloserine containing organic and inorganic compounds. Composite particles were manufactured with a 1:1 weight ratio of organic/inorganic compounds and cycloserine. The influence of organic/inorganic compounds on the stability of cycloserine was investigated under accelerated stress conditions at 60°C/75% RH for 24 hours. In addition, the properties of the composite particles were evaluated using differential scanning calorimetry (DSC), scanning electron microscopy (SEM), and the dissolution of the drug was assessed by preparing it as a hard capsule. Among the organic and inorganic compounds investigated, calcium hydroxide most improved the stability of cycloserine under accelerated stress conditions (53.3 ± 2.2% vs 1.7 ± 0.2%). DSC results confirmed the compatibility between calcium hydroxide and the cycloserine, and SEM results confirmed that it was evenly distributed around the cycloserine. Calcium hydroxide also showed more than 90% cycloserine dissolution within 15 minutes. Therefore, the calcium hydroxide and cycloserine composite particles may be candidates for cycloserine oral pharmaceuticals with enhanced drug stability.

Reducing Calcium Dissolution in Tunnel Shotcrete: The Impact of Admixtures on Shotcrete Performance.

Groundwater infiltration into tunnels causes water to percolate through the fissure channels in the initial support shotcrete. This results in the dissolution and outflow of calcium hydroxide, a key product of cement hydration. This process significantly incurs the formation of crystallization blockages in the tunnel drainage systems. Optimizing the shotcrete mixing ratio is a feasible way to mitigate these blockages. Therefore, this study conducts calcium dissolution tests to investigate the impact of six admixtures, namely, antialkali agent, nanosilica, nanosilica carbonate, fly ash, sodium methyl silicate waterproofing agents, and silane waterproofing agents, on calcium dissolution resistance. Also, mechanical and microscopic tests are carried out to examine their impact on the strength and pore structure of the shotcrete. The objective of this study is to determine the optimal admixture for enhancing the calcium dissolution resistance of shotcrete. Results indicate that the antialkali agent significantly reduces the calcium leaching content of shotcrete. When the dosage is 14%, the calcium leaching amount is reduced by 68.4% in 28 days. Followed by nanosilica and silane waterproofing agents, with optimal dosages of 12 and 0.4%, respectively, the dissolution amount of calcium ions in shotcrete was reduced by 32.87 and 26.5%, respectively. Fly ash curing for 28 days can also reduce the calcium ion dissolution of shotcrete, while nanocalcium carbonate and sodium methyl silicate have little effect on the calcium dissolution of shotcrete. The antialkali agent with a strong calcium ion dissolution effect can improve the tensile strength of shotcrete under long-term curing conditions, which can be increased by 52%, but it compromises the growth of compressive strength. Nanosilica, fly ash, and silane waterproofing agents can improve both the compressive strength and tensile strength of shotcrete under long-term curing conditions. Specifically, at 28 days of curing, the compressive strength increased by 16.83, 28.8, and 20% and the tensile strength increased by 50.24, 60, and 64.5%. In addition, the microscopy results show that the antialkali agent, nanosilica, and silane waterproofing agents promote the hydration process of cement to form ettringite with a low and stable calcium-silicon ratio and reduce calcium hydroxide crystals. Nanosilica and silane waterproofing agents optimize the pore distribution in shotcrete by increasing beneficial pores, decreasing harmful pores, and reducing total porosity.

Evaluation of calcium hydroxide root canal filling materials by cone beam computed tomography and three-dimensional modeling.

The aim of this study was to compare the effectiveness of filling pastes in resin prototype primary molars by cone beam computed tomography (CBCT) and 3D modeling.

Feasibility and mechanism of high alumina cement-modified chlorine saline soil as subgrade material

Soil salinization is a serious problem during ground improvement and foundation construction around the coastal region. This study used high alumina cement (HAC) as a soil stabilisation agent to modify the coastal chlorine saline soil as roadbed backfilling materials. In addition, Ordinary Portland cement (OPC), slaked lime (SL) and fly ash (FA) were used to better the understanding of the chlorine fixation and roadbed performance. The microstructures of different hydration products were investigated through the utilization of the X-ray diffraction and scanning electron microscope equipped with an energy dispersion spectrometer. The HAC-SL-modified soil depicts that the aluminium and calcium phases are beneficial to the formation of Friedel’s salt and hydration products. The optimal chlorine fixation is approximately 20.5% at 6% HAC-SL incorporation (3% of HAC and 3% SL). At the early stage of curing, the strength of the HAC-treated soil is high. However, with a prolonged curing period, there is a slight decrease in the strength because the porosity will increase during the transformation of metastable CAH10 and C2AH8 into stable and dense C3AH6. This evolution can be prevented by incorporating SL to enrich calcium silicate hydrate (C-S-H) and calcium aluminate hydrate (C-A-H). Furthermore, it is of key importance to mention that HAC reaction is quick, therefore, the compaction should be undertaken instantly to ensure the road performance.

The Preparation and Dust Suppression Performance Evaluation of Iron Ore Tailing-Based Cementitious Composites.

In order to comprehensively utilize iron ore tailings (IOTs), the possibility of using IOTs as raw materials for the preparation of cementitious composites (IOTCCs) was investigated, and IOTCC was further applied to mine interface pollution control. The mechanical properties, hydration products, wind erosion resistance, and freeze-thaw (F-T) cycle resistance of IOTCCs were evaluated rigorously. The activity index of iron tailings increased from 42% to 78% after grinding for 20 s. The IOTCC was prepared by blending 86% IOT, 10% ground granulated blast-furnace slag (GGBS), and 4% cement clinker. Meanwhile, the hydration products mainly comprised ettringite, calcium hydroxide, and C-S-H gel, and they were characterized via XRD, IR, and SEM. It was observed that ettringite and C-S-H gel were principally responsible for the strength development of IOTCC mortars with an increase in curing time. The results show that the kaolinite of the tailings was decomposed largely after mechanical activation, which promoted the cementitious property of IOT.

NA-ALGINATE BEADS OF CALCIUM / IRON-LAYERED DOUBLE HYDROXIDE FOR TREATING WATER CONTAMINATED WITH AMOXICILLIN ANTIBIOTIC

The objective of this study was to prepare an adsorbent material from eggshells of chicken banished to the ambient as wastes to satisfy the ecological requirements of sustainable. The preparation process based on the extraction of calcium ions from eggshells and these ions must be reacted with iron to form nanoparticles of (Ca/Fe)-layered double hydroxides (LDHs) which immobilized as Na-alginate beads. Molar ration of calcium to iron, pH and dosage of LDH nanoparticles must be equal to 1, 12 and 5 g/100 mL to ensure that the prepared beads have highest ability to remove of Amoxicillin (AMOX) antibiotic with removal efficiency equal to 32% for operational conditions of Co=100 mg/L, beads dosage=0.5 g/50 mL, speed=200 rpm, pH=7 for 3 hrs. To increase this efficiency to ≥ 90%, best conditions must be time 90 min, pH 7, and beads mass 1.2 g/ 50 mL for Co 100 mg/L at 200 rpm in the batch mode. The Pseudo second order has high capability in the description of such tests with coefficient of determination (R2) ≥ 0.9924 and sum of squared error (SSE) ≤ 0.1287. Hence, the sorption of AMOX onto beads is governed by the chemisorption process. The reflections of XRD analysis proved the presence of (Ca/Fe)-LDH nanoparticles with size of 13.49 nm, calcium hydroxide (Ca(OH)2) and calcium carbonate (CaCO3)

Preparation and hydration of low-carbon UHPC with high fraction of activated tuff and recycled fine powders

Due to the high energy consumption and carbon emission of cement, using active supplementary materials in concrete is widely studied. In this paper, waste tuff micropowder and recycled fine powder (RFP) with maximum replaced ratio of 70 % were investigated by alkali activation in ultra-high performance concrete (UHPC), the mechanical properties and hydration process were studied with different dosages and activators. The results show that the strength activity index of tuff and RFP both enhanced after calcium hydroxide activation. The alkali activator accelerated the hydration speed of tuff and RFP, also leaded to a low heat generated. The compressive strength was reduced with the replaced ratio of tuff and RFP, but the flexural strength was improved once tuff added and cured in appropriate temperature. In the cement-tuff/RFP system, calcium hydroxide accelerates cement hydration and activates part of the tuff and RFP to generate C-(A)-S-H to improve the strength of the mortar. Due to the low degree of tuff activation, less hydration products were formed, leaded to an increase in porosity. The RFP was effectively activated by calcium hydroxide, and the generated C-(A)-S-H and CaCO3 effectively refined the pore structure. The activation of RFP consumed limited mixing water, while the excessive CaCO3 generated by activation will cause the loss of UHPC strength.

Nitrogen-Rich Sewage Sludge Mineralized Quickly, Improving Lettuce Nutrition and Yield, with Reduced Risk of Heavy Metal Contamination of Soil and Plant Tissues

Sewage sludge should primarily find use in agriculture, reducing the quantity directed towards alternative disposal methods like incineration or deposition in municipal landfills. This study evaluated the agronomic value and the risk of soil and plant tissue contamination with heavy metals in sewage sludge obtained from two wastewater treatment plants (WWTP). The experiment was arranged as a 2 × 5 factorial (two sewage sludges, five sanitation treatments), involving lettuce cultivation in pots over two growing cycles. The two sewage sludges were sourced from the WWTPs of Gelfa and Viana do Castelo and underwent five sanitation and stabilization treatments (40% and 20% calcium oxide, 40% and 20% calcium hydroxide, and untreated sewage sludge). The Gelfa sewage sludge, characterized by a higher initial nitrogen (N) concentration, resulted in greater dry-matter yield (DMY) (12.4 and 8.6 g plant−1 for the first and second growing cycles, respectively) compared to that from Viana do Castelo (11.0 and 8.1 g plant−1), with N release likely being a major factor influencing crop productivity. The high N concentration and the low carbon (C)/N ratio of sewage sludge led to rapid mineralization of the organic substrate, which additionally led to a higher release of other important nutrients, such as phosphorus (P) and boron (B), making them available for plant uptake. Alkalizing treatments further stimulated sewage sludge mineralization, increasing soil pH and exchangeable calcium (Ca), thereby enhancing Ca availability for plants, and indicating a preference for use in acidic soils. Cationic micronutrients were minimally affected by the sewage sludge and their treatments. The concentrations of heavy metals in the sewage sludge, soils, and lettuce tissues were all below internationally established threshold limits. This study highlighted the high fertilizing value of these sewage sludges, supplying N, P, and B to plants, while demonstrating a low risk of environmental contamination with heavy metals. Nevertheless, the safe use of sewage sludge by farmers depends on monitoring other risks, such as toxic organic compounds, which were not evaluated in this study.

Effect of nanosilica and fiber on mechanical properties and microstructure of recycled coarse aggregates road concrete

Recycled coarse aggregate has its own characteristics of large porosity, high water absorption and high crushing index, which adversely affects the mechanical strength and durability of recycled aggregate concrete. In this study, the mechanical properties, durability and microstructure of recycled aggregate concrete (RAC) modified with nano-SiO2 (NS) and fibres were investigated to prepare road RAC, using NS polypropylene fibres (PPF) and basalt fibres (BF) as test variables. Compared with RAC only incorporating NS, NS and fibre synergism can significantly enhance the mechanical properties of recycled concrete, compressive strength increased by 27–51 %, flexural strength increased by 12 %, and abrasion resistance increased by 25–72 %. The synergistic effect of NS and PPF significantly improves the frost resistance of recycled concrete. NS has a volcanic ash effect which can react with calcium hydroxide to produce a large number of C-S-H in the secondary hydration reaction, making the internal structure of the cement matrix denser. Interfacial transition zone microstructure is more compact, thus interfacial transition zone porosity is effectively reduced. The hydration products are attached to the fibre surface, which enhances the bonding ability between the fibers and matrix. Therefore, the fibres effectively inhibit the generation and development of internal micro-cracks. NS optimises the internal pore structure of recycled aggregate concrete and enhances the interfacial transition zone, and NS synergistically with PPF can improve the strength and durability of various mechanical properties of recycled concrete. The research results provide the scientific basis for the application of road RAC.

Fracture Resistance of Simulated Immature Teeth Filled with Three Types of Calcium Silicate Cement after Intracanal Medication with Ca(OH)2: An Ex Vivo Study.

The aim of this study was to evaluate the 1-day fracture resistance of simulated immature teeth with an apical plug with ProRoot MTA, MTA Angelus, and RetroMTA after calcium hydroxide intracanal medication. Sixty extracted, single-rooted human mandibular premolars were randomly divided into six groups of 10 teeth each. Firstly, to standardize the 9 mm root length, the crowns were cut off at and 9 mm below the cementoenamel junction transversely. Simulations for immature apices were carried out by using No. 1-6 Peeso reamers to pass through the apex to obtain a diameter of 1.7 mm at the apical opening. One group served as a negative control without any treatment, while the other groups received 30 days of calcium hydroxide intracanal medication. Four groups were plugs with 4 mm of ProRoot MTA, MTA Angelus, RetroMTA, and gutta-percha, respectively. The last one was served as a positive control group without filling inside. After 1 day of incubation, specimens were vertically loaded in a universal testing machine at a crosshead speed of 1 mm/min until fracture occurred. The peak load to fracture (Newton) and fracture pattern were recorded. A one-way analysis of variance (ANOVA) followed by Tukey's HSD test was used for data analysis. The highest mean load to fracture was shown in the negative control group (543.33 ± 37.17 N), followed by ProRoot MTA (432.82 ± 68.06 N), MTA Angelus (396.92 ± 59.93 N), RetroMTA (389.08 ± 56.25 N), and gutta-percha (283.28 ± 43.40 N), and the lowest belonged to the positive control group (239.98 ± 27.19 N). The significant differences were found between both the control and experimental groups with an apical plug with calcium silicate cement (p  < 0.05). There were no significant differences among those three apical plugs (p  > 0.05). Apical plugs with ProRoot MTA, MTA Angelus, and RetroMTA had an immediate strengthening effect on simulated immature teeth after calcium hydroxide intracanal medication had been used.

Influence of feedstock selection on cellulosic ethanol production based on densified biomass with calcium hydroxide and regular steam pretreatment

Feedstock selection is a key factor affecting the process of cellulosic ethanol production. Densifying lignocellulosic biomass with chemicals (calcium hydroxide) followed by regular steam autoclave (DLCA(ch)) is an emerging and efficient pretreatment technology. In this study, different crop straws were selected as feedstock in a DLCA(ch) based process for cellulosic ethanol production, and their experimental and economic performances were evaluated. Both single crop straws and mixed crop straws were used and compared as feedstock for DLCA(ch) based biorefinery. Among single crop straws of corn stover, rice straw and wheat straw, wheat straw had the highest ethanol yield and the lowest feedstock cost, with a minimum ethanol selling price of 2.03 $/gal ethanol considering a 10 % internal rate of return and a 2000 tons crop straw per day biorefinery scale. When mixed crop straws were used as the feedstock, both feedstock cost and ethanol production cost were further reduced, and the minimum ethanol selling price was reduced to 2.02 $/gal ethanol. In addition, the use of mixed crop straws has great potential for large scale DLCA(ch) based process for cellulosic ethanol production.

Synthesis and utilization of polyol-modified high specific surface area Ca(OH)2: an investigation.

Calcium hydroxide (Ca(OH)2) finds widespread use in the petrochemical industry, particularly in flue gas desulfurization applications. However, its conventional usage is limited by its inherently low specific surface area, hampering its efficiency. To address this limitation, this study aims to develop a simple and industrially scalable preparation process for Ca(OH)2 with a high specific surface area, thereby enhancing its effectiveness in various applications. This study aimed to develop a preparation process for making Ca(OH)2 with a high specific surface area, suitable for industry and easy to make. Ca(OH)2 with a specific surface area of 41.555 m2/g was successfully synthesized by incorporating polyols during lime digestion. The prepared high specific surface area Ca(OH)2 is more than five times the specific surface area of ordinary Ca(OH)2. Incorporation of polyols within the lime digestion process induces a reduction in both Ca(OH)2 grain size and particle dimensions, concurrently amplifying the specific surface area and optimizing mass transfer efficiency. Specifically, the desulfurization breakthrough time for Ca(OH)2 subject to a 15% triethanolamine modification was notably extended to 879s, surpassing the desulfurization breakthrough time of unaltered Ca(OH)2 by more than tenfold. Moreover, the modified Ca(OH)2 exhibited remarkable efficacy in neutralizing acidic wastewater. A new approach for the preparation of high-performance Ca(OH)2 is proposed in this study, which could facilitate the industrial production of Ca(OH)2 with high specific surface area.

Diacetylcurcumin: a novel strategy against Enterococcus faecalis biofilm in root canal disinfection.

Aim: We evaluated Diacetylcurcumin (DAC), a derivative of curcumin, for its antibacterial and antibiofilm properties against Enterococcus faecalis. Methods: Minimum inhibitory concentration (MIC) and minimum bactericidal concentration were determined, along with antibiofilm potential and toxicity in Galleria mellonella. Additionally, in silico computational analysis was performed to understand its mechanisms of action. Results & conclusion: DAC demonstrated significant antibacterial effects, with MIC and MBC values of 15.6 and 31.25μg/ml, respectively, and reduced biofilm formation. A synergistic effect, reducing biofilm by 77%, was observed when combined with calcium hydroxide. G. mellonella toxicity tests confirmed DAC's safety at tested concentrations, suggesting its potential for use in root canal disinfection products.

Microbiological assessment of success and failure in pulp revitalization: a randomized clinical trial using calcium hydroxide and chlorhexidine gluconate in traumatized immature necrotic teeth

ABSTRACT Aim To compare differences in the disinfection efficacy of calcium hydroxide (CH) and chlorhexidine gluconate (CHD) dressings in pulp revitalization (PR) of traumatized immature necrotic teeth; to investigate the microflora in successful/failed PR and whether bacterial persistence influences the outcomes of PR. Methods Microbiological assessment of the average bacterial load (CFU/sample) and bacterial diversity (taxa/sample) was performed on 41 teeth at three timepoints (S2-before, S3-after debridement and S5- after root canal dressing). Results The primary microflora was more diverse in successful cases than in failed. Decreases in CFU/sample and taxa/sample occurred S2 - S3, though new increases occurred at S5 in the CHD subgroup (successful and failed) and CFU/sample in the CH subgroup (failed). At S5, the successful cases showed more bacterial decreases. No specific species was associated with the outcomes with no statistical differences between the disinfection efficacy. Conclusions There were no statistical differences in CH and CHD efficacy. At S5, microflora persisted in both successful and failed outcomes, but the abundance and diversity increased significantly only in the failed cases. The successful outcomes presented higher diversity and higher decreases of the primary microflora at S5 than the failed outcomes. The abundance and diversity increased significantly at S5 only in failed cases.

Assessment of Long-Term Success and Survival Rates of Different Types of Intracanal Medicaments

ABSTRACT Background: Antimicrobial endodontic intracanal medicaments play a vital role along with biomechanical preparation in the elimination of bacteria present in the pulp area to achieve success in endodontic therapy. Aim: The present research was conducted with the objective of evaluating and comparing intracanal medicaments regarding antibacterial properties against Enterococcus faecalis. Materials and Methods: One hundred and twenty healthy human premolars of the mandible were used. All premolar crowns were removed, keeping the standardized length of the root as 15 mm. Category 1 received triple antibiotic paste (TAP) (n = 30), Category 2 received double antibiotic paste (DAP) (n = 30), Category 3 received augmentin (n = 30), and Category 4 received calcium hydroxide (n = 30). Hygienic paper points were placed in each root canal, then they were moved to a tube containing 1 mL of brain-heart infusion medium and left there for bacteriological testing. Colony-forming units (CFUs) of E. faecalis were then observed and counted after the plates had been incubated overnight at a temperature of 37°C. Results: During intracategory comparisons, there was a significant reduction in colonies of E. feacilis in each category (P ≤ 0.001). When there were intercategory comparisons, there was a maximum reduction in CFU in specimens of Category 1 (TAP) followed by Category 3 (Augmentin) and Category 2 (DAP). Conclusion: Intracanal medicaments like TAP, DAP, and augmentin are effective against root canal E. faecalis.

Solid solutions among cement AFm phases containing nitrate and nitrite ions

The AFm phase found in hydrated Portland cements refers to a family of calcium aluminate phases. Their layer structure is derived from that of portlandite (calcium hydroxide (Ca(OH)2)), but with one third of the Ca2+ ions replaced by a trivalent ion, nominally Al3+ or Fe3+. The resulting charge imbalance gives the layers a positive charge, which is compensated by intercalated anions; the remaining interlayer space is filled with water (H2O). Hydrated cements will contain mixtures of AFm phases and their solid solutions. Portland cement is often modified by addition of soluble nitrate or nitrite salts to protect embedded steel or to shorten the setting time. These nitrate and nitrite ions are capable of entering and occupying AFm anion sites, hence impacting overall phase balances between cement hydrates. In this study AFm phases and solid solution formations were investigated between AFm phases containing SO42−, CO32−, OH−, Cl− and NO2− NO3− ions. Samples were synthesised and subsequently characterised using X-ray diffraction and through the measurement of aqueous solution compositions after 180 days of equilibration in water.

Ways of Maintaining Pulp Vitality: Narrative Literature Review

Background: Dental caries is a prevalent global health issue, affecting a significant portion of the population and impacting social and personal well-being. Traditional methods focused on aggressive caries removal, but recent advances emphasize the importance of preserving pulp vitality through minimal invasive techniques. Objective: To evaluate the efficacy of various vital pulp therapy techniques including indirect and direct pulp capping and pulpotomy, and to analyze the effectiveness of new biomaterials in preserving dental pulp vitality in teeth affected by caries or trauma. Methods: A systematic literature review was conducted using the Islamabad Medical and Dental College library and online databases such as PubMed and Google Scholar. The review included peer-reviewed articles that discussed vital pulp therapy, materials used in pulp capping, and their outcomes. Articles were selected based on inclusion and exclusion criteria with no date restrictions, focusing solely on literature published in English. Results: The review identified 32 relevant studies, indicating a shift towards less invasive procedures that prioritize dental pulp preservation. Innovations in biomaterials such as Mineral Trioxide Aggregate (MTA), Biodentin, and resin-based MTA have shown to enhance healing outcomes and are increasingly preferred over traditional materials like Calcium Hydroxide due to their superior properties and clinical results. Conclusion: Vital pulp therapies are crucial for managing teeth with deep carious lesions or trauma, offering a conservative alternative to more invasive treatments. These therapies are instrumental in maintaining the structural integrity and health of natural teeth, thus reducing the need for extensive dental procedures and promoting overall oral health.

Sustainable and Environmentally Friendly Microwave Synthesis of Nano-Hydroxyapatite from Decarbonized Eggshells.

The sustainable microwave (MW) synthesis of hydroxyapatite (HAp) from decarbonized eggshells was investigated. Decarbonization of eggshells, as a natural source of calcium carbonate (CaCO3), was carried out in the current study at ambient conditions to reduce the footprint of CO2 emissions on our environment where either calcination or acidic direct treatments of eggshells produce CO2 emissions, which is a major cause for global warming. Eggshell decarbonization was carried out via the chemical reaction with sodium hydroxide (NaOH) alkaline solution in order to convert eggshell waste into calcium hydroxide (Ca(OH)2) and simultaneously store CO2 as a sodium carbonate (Na2CO3) by-product which is an essential material in many industrial sectors. The produced Ca(OH)2 was mixed with ammonium dihydrogen phosphate (NH4H2PO4) reagent at pH~11 before being subjected to MW irradiation at 2.45 GHz frequency for 5 min using 800 Watts to prepare HAp. The prepared Nano-HAp was characterized using X-ray diffraction (XRD) where the crystal size was ~28 nm using the Scherrer equation. The elongated rod-like nano-HAp crystals were characterized using scanning electron microscopy (SEM) equipped with dispersive energy X-ray spectroscopy (EDS), Fourier transform infrared spectroscopy (FTIR), and transmission electron microscopy (TEM). MW synthesis of decarbonized eggshells is considered as a sustainable and environmentally friendly route to produce promising bioceramics such as nano-HAp. Concurrently, decarbonization of eggshells offers the ability to store CO2 as a high value-added Na2CO3 material.