Calcium Hydroxide

• CAS: 1305-62-0
• Catalog Number: ACM1305620-4
• Category: Main Products
• Molecular Weight: 74.09
• Molecular Formula: H2CaO2
• Description: Calcium hydroxide is an odorless white granules. Sinks in water. (USCG, 1999);White powder;COLOURLESS CRYSTALS OR WHITE POWDER.;White, odorless powder.;White, odorless powder. [Note: Readily absorbs CO2 from the air to form calcium carbonate.]
• Synonyms: Calcium dihydoxide
• IUPAC Name: calcium dihydroxide
• Canonical SMILES: [OH-].[OH-].[Ca+2]
• InChI: InChI=1S/Ca.2H₂O/h;2*1H2/q+2;;/p-2
• InChI Key: AXCZMVOFGPJBDE-UHFFFAOYSA-L
• Boiling Point: 2850 °C
• Melting Point: 580 °C
• Flash Point: /Calcium Hydroxide is/ non flammable
• Density: 2.24 g/mL at 25 °C (lit.)
• Solubility: 0.2 % at 32° F (NIOSH, 2016);Slightly soluble in water. Insoluble in ethanol. Soluble in glycerol;In water, 1730 mg/L at 20 °C;In water, 0.160 g/100 g water at 20 °C;Very slightly soluble in boiling water. Insoluble in alcohol.;Soluble in acid;Soluble in glycerol, sugar or ammonium chloride solution; soluble in acids with evolution of much heat;Solubility in water: none;(32°F): 0.2%
• Appearance: White solid
• Storage: Store at +5 °C to +30 °C
• Autoignition Temperature: Not flammable (USCG, 1999)
• Color/Form: Crystals or soft granules or powder;Soft, hexagonal crystals;Rhombic, trigonal, colorless crystals;Soft, white crystalline powder;White powder [Note: Readily absorbs CO2 from the air to form calcium carbonate]
• Complexity: 0
• Covalently-Bonded Unit Count: 3
• Decomposition: 580 °C
• EC Number: 215-137-3
• Exact Mass: 73.968
• Formal Charge: 0
• Hazard Statements: Xi:Irritant
• H-Bond Acceptor: 2
• H-Bond Donor: 2
• Heavy Atom Count: 3
• ICSC Number: 0408
• MDL Number: MFCD00010901
• Monoisotopic Mass: 73.968
• Odor: Odorless
• Other Experimental: Loses water when ignited to form calcium oxide; forms CaO;Loses water at 580 °C;Solubility in water is decreased by the presence of fixed alkali hydroxides.;Bulk density: 450 to 640 kg/cu m. In the as-poured state, it can be as low as 350 kg/cu m, owing to air entrapment;Lime salts, ... are various calcium containing compounds having the property of being corrosive to ... metals. /Lime salts, ... (corrosive solid, nos)/;Readily absorbs carbon dioxide from the air, forming CaCO3;Heat of formation = -6.1078X10+08 J/kmol
• Packing Group: III
• Physical State: White Powder
• Refractive Index: Index of refraction: 1.574 (alpha), 1.545 (beta)
• Rotatable Bond Count: 0
• RTECS Number: EW2800000
• Safety Description: S26-S39
• Stability: Readily absorbs carbon dioxide from air forming calcium carbonate.
• UNII: PF5DZW74VN
• Vapor Pressure: 0 mm Hg (approx) (NIOSH, 2016);0 mmHg (approx);0 mmHg (approx)
• WGK Germany: 1

Case Study

Mechanism of Calcium Hydroxide as a Pulp-Capping Agent in Tertiary Dentin Formation

Sangwan, P., et al. International endodontic journal, 2013, 46(1), 3-19.

Calcium hydroxide (Ca(OH)2) is widely used as a pulp capping agent in dentistry, and its mechanism of action on tertiary dentin formation has been extensively studied. This work summarizes the various possible mechanisms by which Ca(OH)2 induces dentin formation during pulp capping.
· The release of bioactive molecules, whether through direct stimulation of cells or through dissolution of the dentin extracellular matrix, is crucial for the biological effects of Ca(OH)2. In vitro experiments have demonstrated that Ca(OH)2 can dissolve bioactive molecules previously sequestered in the dentin matrix.
· Calcium and hydroxyl ions released from the material regulate the events leading to tertiary dentin formation. High concentrations of Ca++ in the local environment can activate stem cells, osteoblasts, and cell fibers, promote migration, and regulate various cellular events such as proliferation, differentiation, and mineralization.
· The cement containing Ca(OH)2 and the microcrystals deposited on its surface provide a bioactive matrix for the adsorption of biomolecules and the adhesion of odontoblasts.
· In addition, the nonspecific, antibacterial, and anti-inflammatory effects of Ca(OH)2 on the dental pulp may aid the mineralization process. The pH of Ca(OH)2 (approximately 12.5) denatures structural and enzymatic proteins, destroys cytoplasmic membranes and genetic material, and thus eliminates bacterial contamination. Ca(OH)2 is able to modulate proinflammatory cytokines, which may mitigate their destructive effects on dental pulp tissue.

Calcium hydroxide in dentistry

Lačević, Amela, Edina Vranić, and Irfan Zulić. Biomolecules and Biomedicine 3.4 (2003): 26-29.

Calcium hydroxide has a hard tissue inducing effect. It is a powder that can be mixed with saline to form a paste. The paste is strongly alkaline with a pH of 12.5, and its application to the pulp leads to partial necrosis of the coronal pulp tissue, but shows no or only a mild inflammatory reaction. Analyzing the pH and calcium ion concentration in the apical region, it is clear that the bactericidal activity of calcium hydroxide requires at least 2 weeks. When placed in a restoration, calcium hydroxide can retain its antimicrobial properties for about two months, after which it degrades to calcium oxide and other less effective calcium salts. The shelf life of all calcium hydroxide preparations is limited, as they eventually turn into calcium oxide. Calcium hydroxide can be used as a liner for indirect and direct pulp cupping, root dressings, root canal sealers, apical sealing. The carrier plays a supporting role, imparts chemical properties to the paste, such as dissociation and diffusion, and facilitates the correct filling of the root canal, which is a decisive factor for antimicrobial potential and tissue healing. The mechanism of action of calcium hydroxide on tissue, inducing mineralized tissue deposition, is an extremely important aspect of calcium hydroxide indications as it demonstrates the biocompatibility of calcium hydroxide.
Ion dissociation and diffusion are essential for activity inside the dentinal tubules. Changes in dentin pH caused by hydroxyl ions are slow and depend on several factors that can alter the rates of ion dissociation and diffusion, such as the water solubility level of the vehicle used, viscosity differences, acid-base properties, dentin permeability, and the level of existing calcification. Following placement of calcium hydroxide paste, the pH of the outer surface of dentin ranges from 7 to 8, depending on the root third, and the pH inside the root canal remains at 12.6 for 1 to 60 days.

Antimicrobial properties of calcium hydroxide dressings

Sharma, Garima, et al. Australian Endodontic Journal 44.1 (2018): 60-65.

Studies have examined the association between contact time of calcium hydroxide dressings within the root canal and their antimicrobial properties. Results showed that the antimicrobial effects of calcium hydroxide were comparable for contact times between 7 and 45 days. Two studies yielded conflicting results when exposure time was extended beyond 45 days. Future studies are necessary to investigate and optimize the long-term application of calcium hydroxide and to determine the potential benefits of its use in clinical settings.
The antimicrobial efficacy of CH is associated with the release of hydroxyl ions, which are highly oxidizing free radicals that are extremely reactive toward a variety of biomolecules. This effect has been associated with cytoplasmic membrane and DNA damage and protein denaturation, and the release of hydroxyl ions is associated with a local increase in pH levels. Among the many studies investigating the relationship between CH contact time and changes in root dentin pH, two seminal studies are noteworthy and yielded contrasting results. One study found that pH within dentin increased rapidly within hours, with a peak pH value reached after 2-3 weeks. However, a second study found that the pH of the root dentin surface peaked on the first day, with a subsequent decrease in pH until a plateau was reached after 18 days. The difficulty in achieving a consistently high pH in the peripheral region can be attributed to dentin devitalization, the time interval required for hydroxide ions to diffuse into the dentinal tubules, and complex anatomical changes. Finally, pH may be affected by factors such as the CH concentration in the formulation and, possibly, the vehicle used.

Custom Reviews

August 05, 2023

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Highly recommended
The quality of the platform is very good, and calcium hydroxide has many packaging specifications and wide selection.

Custom Q&A

What is the molecular formula of Calcium Hydroxide?

The molecular formula of Calcium Hydroxide is CaH2O2.

What are some synonyms for Calcium Hydroxide?

Some synonyms for Calcium Hydroxide include calcium hydrate, calcium dihydroxide, Kalkhydrate, Biocalc, Kemikal, Calbit, Calvit, Limbux, Super Microstar, Bell mine, Rhenofit CF, and more.

What is the CAS number of Calcium Hydroxide?

The CAS number of Calcium Hydroxide is 1305-62-0.

How is the IUPAC name of Calcium Hydroxide computed?

The IUPAC name of Calcium Hydroxide, which is calcium;dihydroxide, is computed by Lexichem TK 2.7.0.

What is the InChI of Calcium Hydroxide?

The InChI of Calcium Hydroxide is InChI=1S/Ca.2H2O/h;2*1H2/q+2;;/p-2. It is computed by InChI 1.0.6.

What is the InChIKey of Calcium Hydroxide?

The InChIKey of Calcium Hydroxide is AXCZMVOFGPJBDE-UHFFFAOYSA-L. It is computed by InChI 1.0.6.

What is the molecular weight of Calcium Hydroxide?

The molecular weight of Calcium Hydroxide is 74.09 g/mol.

How many hydrogen bond donor counts does Calcium Hydroxide have?

Calcium Hydroxide has 2 hydrogen bond donor counts, computed by Cactvs 3.4.8.18.

How many hydrogen bond acceptor counts does Calcium Hydroxide have?

Calcium Hydroxide has 2 hydrogen bond acceptor counts, computed by Cactvs 3.4.8.18.

How many rotatable bond counts does Calcium Hydroxide have?

Calcium Hydroxide has 0 rotatable bond counts, computed by Cactvs 3.4.8.18.