The following chemically bond to the tooth:
A- Composite resin.B- Dental sealants.
C- Glass ionomer cement.***
D- All of the above.
Glass Ionomer cement is the generic name of a group of materials that arises after the reaction of silicate glass powder and polyalkenoic acid. At first, this dental cement was intended to be used in aesthetic restorations for anterior teeth, especially for class III and V cavities.
But seeing its adherence to the dental structure and its validity for caries prevention, it was extended to other uses. as: Cementing agent, groove and fissure sealer, coating, stump reconstruction and immediate restorations among others.
Over time, its components have undergone many modifications, and today, conventional cement is composed of:
- POWDER: Silica, Alumina, Fluorides
- LIQUID: Polyacrylic acid, itaconic acid, tartaric acid.
When both components are mixed (mixing should be quick, between 20 and 30 seconds at a dose of powder / liquid 1: 5: 1.) In a paste, the acid etches the surfaces of the glass particles so that ions are released from calcium, sodium, aluminum and fluorine to the aqueous medium.
Glass ionomers have an acid-base chemical reaction, in which there is an ionic exchange between Ca and carboxyl group. This setting reaction starts when the liquid comes into contact with the powder.
The H + ions attack the glass particles releasing Ca, Al and F decomposing the glass by acid, forming a silica gel.
Next, Ca reacts with polyacids and then with Al. This polyacrylate metal salt begins to precipitate and gelation begins until it hardens.
Water is an important component in the setting as it acts as a plasticizer reducing stiffness, therefore, during placement in the tooth should not be dried as it can contribute to a brittle material and the excess of this favors its dissolution.
Among its advantages we have the release of Fluoride which favors bacteriostatic activity, compressive strength greater than zinc phosphate, being similar tensile strength, easy handling and translucent.
The high molecular weight of its acid component initially has an acidic pH but rapidly increases after mixing has started avoiding pulp toxicity. However, it is very soluble in moisture, so it requires absolute isolation.
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