- Temporary or semi-permanent fillings
- To cement in position crowns, inlays, and bridges.
- To line cavities in order to prevent thermal or chemical damage to the pulp.
- Support of remaining weak tooth structure.
The main Dental cements used are :
- Zinc oxide and eugenol
- Accelerated zinc oxide eugenol.
- Specific zinc oxide eugenol products.
- EBA cements.
- Zinc polycarboxylates.
- Zinc and copper phosphates.
- Glass-ionomer cements.
Zinc oxide and eugenol
Uses of zinc oxide and eugenol
- Protective cavity sub-linings (over which an oxyphosphate lining is placed for resistance to packing and biting pressure).
- Sedative or obtundent (soothing) dressings(eugenol relieves painful hyperemia of the pulp).
- Temporary fillings.
- Pulp caps.
- Root canal fillings.
- Periodontal packs.
Properties of zinc oxide and eugenol
- Consists of a liquid and powder:-powder consists of zinc oxide, magnesium oxide, and zinc acetate (an accelerator ). liquid contains eugenol, olive oil, and acetic acid as an accelerator.
- Sedative action on pulp.
- Prevent conduction of heat to the pulp.
- Very soluble in water.
- Very weak.
For more information: Properties and uses of dental fillings
Accelerated zinc oxide-eugenol
Special zinc oxide-eugenol products
EBA Dental cements
- The powder contains zinc oxide, fused quartz, and hydrogenated rosin.
- Liquid consists of eugenol and O-ethoxy benzoic acid.
As much as seven parts of powder are added to one of liquid in order to improve the mechanical properties.
Uses of polycarboxylates
- Cementation of fixed orthodontic appliances.
- Cavity linings.
Properties of zinc polycarboxylates
They originally consisted of :
- Powdered zinc oxide with small quantities of magnesium oxide.
- A liquid of approximately 40 percent aqueous solution of polyacrylic acid.
- Products with two liquids of different viscosities; a thinner liquid for cementing and a vicious one for cavity lining.
- Two products with polyacrylic acid in the powder. The liquids for these contain 95 percent water. One product is encapsulated for mechanical mixing.
- Encapsulated material with about 43 per cent alumina on the powder.
- One product with a polymer slightly different to polyacrylic acid.
- One cement contains stannous fluoride.
- Very adhesive to clean dry enamel.
- Saliva considerably reduces the adhesive strength.
- Adheres better to a smooth surface than to a rough one (in contrast to zinc phosphates).
- Adhesion to dentine is not as good as to enamel.
- Does not adhere well to gold or porcelain.
- Adheres to stainless steel.
- Little irritant effect on the pulp.
- More soluble than zinc phosphate materials.
- Good thermal insulation properties.
Zinc Oxyphosphate Uses
- Consists of a powder and a liquid: Powder is mainly zinc oxide, plus magnesium oxide,and other oxides. Liquid is mostly an aqueous solution of phosphoric acid.
- Highly acidic, so deep cavities require a sub-lining to protect the pulp.
- Stronger than zinc oxide-eugenol.
- Good thermal insulator.
- Does not adhere well to enamel or dentine.
The required amount of liquid and powder are mixed with a stainless steel spatula on a clean, cool glass slab. The quantity of powder incorporated varies according to the purpose for which it is required:
- As a lining, thick mix for strength and lessened risk of pulpal damage as there is a lower proportion of acid.
- As a cement, slightly thinner to provide a reduced thickness of cement between crown and tooth.
One minute is the usual time for speculation.
Uses of copper dental cements
- To cement splints to the teeth of patients with fractured jaws.
Properties of copper dental cements
- It is similar to zinc phosphate cement, but the powder contains a copper compound in addition to zinc oxide. The color varies according to the type of copper oxide:-
Red if cuprous oxide.
Glass-ionomer (ASPA) dental cements.
Uses of Glass-ionomer dental Cement
- Erosion cavities.
- Deciduous restorations.
- Cementation of porcelain crowns.
- Fissures sealants.
- Consists of a powder and liquid.Powder relates to silicates, consisting of fused quartz and alumina.
- Liquid consists of a 50 per cent solution of polyacrylic acid, stabilized to prevent gelling and thickening.
- Has adhesive properties similar to zinc polycarboxylate cement.
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