Zinc oxide eugenol (ZOE) is a material created by the combination of

zinc oxide Zinc oxide is an inorganic compound with the formula . It is a white powder that is insoluble in water. ZnO is used as an additive in numerous materials and products including cosmetics, food supplements, rubbers, plastics, ceramics, glass, cemen ...

and

eugenol Eugenol is an allyl chain-substituted guaiacol, a member of the allylbenzene class of chemical compounds. It is a colorless to pale yellow, aromatic oily liquid extracted from certain essential oils especially from clove, nutmeg, cinnamon, basil ...

contained in

oil of cloves Oil of clove, also known as clove oil, is an essential oil extracted from the clove plant, ''Syzygium aromaticum''. Clove oil is commonly used in aromatherapy and for flavoring food and some medicines. Madagascar and Indonesia are the main produce ...

. An acid-base reaction takes place with the formation of zinc eugenolate chelate. The reaction is catalysed by water and is accelerated by the presence of metal salts. ZOE can be used as a dental filling material or

dental cement Dental cements have a wide range of dental and orthodontic applications. Common uses include temporary restoration of teeth, cavity linings to provide pulpal protection, sedation or insulation and cementing fixed prosthodontic appliances. Recent u ...

dentistry Dentistry, also known as dental medicine and oral medicine, is the branch of medicine focused on the teeth, gums, and mouth. It consists of the study, diagnosis, prevention, management, and treatment of diseases, disorders, and conditions o ...

.Jack L. Ferracane, ''Materials in Dentistry: Principles and Applications'', 2001, 2d Edition, Lippincott Williams & Wilkins, Richard van Noort, 2002, ''Introduction to Dental Materials'', 2d Edition, Elsevier Health Sciences, It is often used in dentistry when the decay is very deep or very close to the nerve or pulp chamber. Because the tissue inside the tooth, i.e. the

pulp Pulp may refer to: * Pulp (fruit), the inner flesh of fruit Engineering * Dissolving pulp, highly purified cellulose used in fibre and film manufacture * Pulp (paper), the fibrous material used to make paper * Molded pulp, a packaging material ...

, reacts badly to the drilling stimulus (heat and vibration), it frequently becomes severely inflamed and precipitates a condition called acute or chronic

pulpitis Pulpitis is inflammation of dental pulp tissue. The pulp contains the blood vessels, the nerves, and connective tissue inside a tooth and provides the tooth’s blood and nutrients. Pulpitis is mainly caused by bacterial infection which itself is ...

. This condition usually leads to severe chronic tooth sensitivity or actual toothache and can then only be treated with the removal of the nerve (pulp) called

root canal therapy Root canal treatment (also known as endodontic therapy, endodontic treatment, or root canal therapy) is a treatment sequence for the infected pulp of a tooth which is intended to result in the elimination of infection and the protection of ...

. For persons with a

dry socket Alveolar osteitis, also known as dry socket, is inflammation of the alveolar bone (i.e., the alveolar process of the maxilla or mandible). Classically, this occurs as a postoperative complication of tooth extraction. Alveolar osteitis usually occ ...

as a complication of tooth extraction, packing the dry socket with a eugenol-zinc oxide paste on iodoform gauze is effective for reducing acute pain. The placement of a ZOE "temporary" for a few to several days prior to the placement of the final filling can help to sedate the pulp. But, ZOE had in vitro cytotoxicity majorly due to release of Zn ions, not eugenol. In spite of severe in vitro cytotoxicity, ZOE showed relatively good biocompatibility in animal study when ZOE was applied on dentin. When ZOE was used as dentin-protective based materials, use of dental composite resin on ZOE was strongly prevented due to its inhibition of resin polymerization through radical scavenging effect. It is classified as an intermediate restorative material and has

anaesthetic An anesthetic (American English) or anaesthetic (British English; see spelling differences) is a drug used to induce anesthesia ⁠— ⁠in other words, to result in a temporary loss of sensation or awareness. They may be divided into two ...

and

antibacterial An antibiotic is a type of antimicrobial substance active against bacteria. It is the most important type of antibacterial agent for fighting bacterial infections, and antibiotic medications are widely used in the treatment and prevention of ...

properties. The exact mechanism of anesthetic effect from ZOE was not revealed perfectly, but possibly through anti-inflammatory effect, modulating immune-cells to less inflamed status. It is sometimes used in the management of

dental caries Tooth decay, also known as cavities or caries, is the breakdown of teeth due to acids produced by bacteria. The cavities may be a number of different colors from yellow to black. Symptoms may include pain and difficulty with eating. Complicatio ...

as a "temporary

filling Filling may refer to: * a food mixture used for stuffing * Frosting used between layers of a cake * Dental restoration * Symplectic filling, a kind of cobordism in mathematics * Part of the leather crusting process See also * Fill (disambiguati ...

". ZOE cements were introduced in the 1890s. Zinc oxide eugenol is also used as an impression material during construction of complete

dentures Dentures (also known as false teeth) are prosthetic devices constructed to replace missing teeth, and are supported by the surrounding soft and hard tissues of the oral cavity. Conventional dentures are removable ( removable partial denture o ...

and is used in the mucostatic technique of taking impressions, usually in a special tray, (acrylic) produced after primary alginate impressions. However, ZOE is not usually used if the patient has large undercuts or tuberosities, whereby silicone impression materials would be better suited. Zinc oxide eugenol is also used as an

antimicrobial An antimicrobial is an agent that kills microorganisms or stops their growth. Antimicrobial medicines can be grouped according to the microorganisms they act primarily against. For example, antibiotics are used against bacteria, and antifungals ar ...

additive in paint.

Types

According to ANSI/ADA Specification no:30 (ISO 3107) and depending on intended use and individual formulation designed for each specific purpose: *

Composition

The chemical composition of ZOE is typically:Zinc Oxide Eugenol Impression Pastes -A Study of an impression material- Chung Suck Lee, D.D.S.
/ref> *

Zinc oxide Zinc oxide is an inorganic compound with the formula . It is a white powder that is insoluble in water. ZnO is used as an additive in numerous materials and products including cosmetics, food supplements, rubbers, plastics, ceramics, glass, cemen ...

, ~69.0% * White (bleached) rosin, ~29.3% *

Zinc acetate Zinc acetate is a salt with the formula Zn(CH3CO2)2, which commonly occurs as the dihydrate Zn(CH3CO2)2·2H2O. Both the hydrate and the anhydrous forms are colorless solids that are used as dietary supplements. When used as a food additive, it ha ...

, ~1.0% (improves strength) *

Zinc stearate Zinc stearate is a "zinc soap" that is widely used industrially. In this context, soap is used in its formal sense, a metal salt of a fatty acid: in this case stearic acid. It is a white solid that repels water. It is insoluble in polar solvents ...

, ~0.7% (acts as accelerator) * Liquid (

, ~85%,

olive oil Olive oil is a liquid fat obtained from olives (the fruit of ''Olea europaea''; family Oleaceae), a traditional tree crop of the Mediterranean Basin, produced by pressing whole olives and extracting the oil. It is commonly used in cooking: f ...

~15%) ZOE impression pastes are dispensed as two separate pastes. One tube contains zinc oxide and vegetable or mineral oil; the other contains

and

rosin Rosin (), also called colophony or Greek pitch ( la, links=no, pix graeca), is a solid form of resin obtained from pines and some other plants, mostly conifers, produced by heating fresh liquid resin to vaporize the volatile liquid terpene comp ...

. The vegetable or mineral oil acts as a

plasticizer A plasticizer ( UK: plasticiser) is a substance that is added to a material to make it softer and more flexible, to increase its plasticity, to decrease its viscosity, and/or to decrease friction during its handling in manufacture. Plasticiz ...

and aids in offsetting the action of the eugenol as an irritant.

Oil of cloves Oil of clove, also known as clove oil, is an essential oil extracted from the clove plant, ''Syzygium aromaticum''. Clove oil is commonly used in aromatherapy and for flavoring food and some medicines. Madagascar and Indonesia are the main produce ...

, which contains 70% to 85% eugenol, is sometimes used in preference to eugenol because it produces less burning sensation for patients when it contacts the soft tissues. The addition of rosin to the paste in the second tube facilitates the speed of the reaction and yields a smoother, more homogeneous product. Canada balsam and

Balsam of Peru Balsam of Peru or Peru balsam, also known and marketed by many other names, is a balsam derived from a tree known as ''Myroxylon balsamum'' var. ''pereirae''; it is found in El Salvador, where it is an endemic species. Balsam of Peru is used i ...

are often used to increase flow and improve mixing properties. If the mixed paste is too thin or lacks body before it sets, a filler (such as a

wax Waxes are a diverse class of organic compounds that are lipophilic, malleable solids near ambient temperatures. They include higher alkanes and lipids, typically with melting points above about 40 °C (104 °F), melting to giv ...

) or an inert powder (such as

kaolin Kaolinite ( ) is a clay mineral, with the chemical composition Al2 Si2 O5( OH)4. It is an important industrial mineral. It is a layered silicate mineral, with one tetrahedral sheet of silica () linked through oxygen atoms to one octahedral ...

talc Talc, or talcum, is a Clay minerals, clay mineral, composed of hydrated magnesium silicate with the chemical formula Mg3Si4O10(OH)2. Talc in powdered form, often combined with corn starch, is used as baby powder. This mineral is used as a thi ...

, or

diatomaceous earth Diatomaceous earth (), diatomite (), or kieselgur/kieselguhr is a naturally occurring, soft, siliceous sedimentary rock that can be crumbled into a fine white to off-white powder. It has a particle size ranging from more than 3 μm to le ...

) may be added to one or both of the original pastes.

References

A D Wilson and J W Nicholson, Acid-Base Cements, 1993, {{ISBN, 0-521-37222-4, Chapter 9 Dental materials oxide eugenol Impression material