There are five different types of cement in the dental field each is versatile in their properties, uses, and mixing techniques. Many were traditionally used for routine cementation through the nineteen ninety’s and since have been replaced by newer makeup and mixing techniques. The selection of cement for a specific procedure requires knowledge of the chemical and physical properties of each particular cement for the specific restorative process to be performed. This first cement I’m going to discuss is Glass Ionomer Cement. Glass ionomer cement is one of the most versatile types of cement in the dental field.
This is a hybrid type of silicate and polycarboxylate cements. This adheres to the enamel, dentin, and metallic materials. They are supplied in 3 different types, type I, type II, and type III. Type I is for cementation of metal restorations and direct-bonded orthodontic brackets, while Type II is designed for restoring areas of erosion near the gingiva. And Type III is used as a liner dentin bonding agent. Glass ionomer has benefits such as it causes less trauma to the pulp; it has low solubility in the mouth, and adheres to a slightly moist tooth surface, etc.
The chemical makeup includes a liquid made of polyacrylic acid copolymer and water while the powder is made of calcium fluoroaluminosilicate glass with barium glass. It is available in light-curing or self-curing formulas. It is supplied in bottles of powder or liquid which can be mixed manually paper pad or a glass slab, as well as in premeasured capsules for expressing through a dispenser. The second type of cement is Composite Resin Cement. Composite resin is a newer cement consisting of composite resin cement.
It is especially designed for ceramic or porcelain inlays, onlays, crowns, and bridges, ceramic veneers, orthodontic bands, direct bonding or orthodontic brackets, and metal-based crowns and bridges. It has physical properties as those of composite resin such as a thin film thickness and virtual insolubility in the mouth. The important aspect of the selection of composite resin cements is the tooth must be free of all plaque and debris and must be etched or treated with a bonding system before cementation. This cement is supplied as a powder and liquid mix in a syringe as a base, or in a light-cured/ dual-cured system.
It is recommended that you mix onto a paper pad rapidly with a spatula. The third type is Zinc Oxide-Eugenol Cement also known as ZOE. This cement is very nonirritating too the pulp and has a soothing effect in the Eugenol that often is used in procedures when postoperative sensitivity may be a concern. There are 2 types of ZOE, Type I id used for temporary cementation or provisional coverage, and Type II is used for permanent cementation of cast restorations or appliances. The chemical makeup is a liquid made of Eugenol, water, acetic acid, zinc acetate, and calcium chloride.
The power consists of zinc oxide, magnesium oxide, and silica. ZOE has a pH balance close to 7. 0 which means it is less acidic than most other cements. This causes it to be less irritating on the tooth, even though it has a strong odor, which may offend some patients. When mixing on a non-absorbent paper pad try not to come in to direct contact with the liquid. When slower set is on a glass slab. For the use of a luting agent, a thinner mix is necessary. The normal setting time for mixing is from 30 to 60 seconds, but in the mouth it is 3 to 5 minutes.
The fourth type of cement is Polycarboxylate Cement. This cement was developed in the 1960’s and was one of the first cements scientifically designed to provide an adhesive bond to the tooth structure. It has changed from its original chemical makeup over the past few years. It was originally polyacrylic acid and has changed over to polyalkenoate cement. This had been used for permanent cement for cast restorations, stainless steel crowns, and orthodontic bands. This maintains its versatility as a nonirritating base under composite and amalgam restorations and intermediate restoration.
The chemical makeup for polycarboxylate cement comes in a liquid made up of polyacrylic acid, itaconic acid, maleic acid, tartaric acid and water, while the powder is made up of zinc oxide, magnesium oxide, aluminum oxide, and different reinforcing fillers. When mixed accordingly, it is similar to zinc phosphate cement in terms of solubility and tensile strength. The pH increases rapidly as the material sets, and 24 hours later, it causes it to become similar to zinc phosphate, but is less irritating to the pulp.
It is supplied in a squeeze bottle or calibrated syringe-type liquid dispenser, which can be mixed on a nonabsorbent paper pad or a cool, dry glass slab.. The fifth and final I’m going to discuss is Zinc Phosphate Cement. This cement is one of the oldest types of dental cements in use and is classified as Type I (fine grain) and Type II (medium grain). Type I is used in permanent cementations such as bridges, crowns, onlays, and inlays. Type II is recommended for the use of insulation of the base for deep cavity preparations. Zinc phosphate omes in a liquid made up of 50% zinc phosphoric acid in water, buffered with aluminum phosphate and zinc salts to control the pH and the powder is 90% zinc oxide and 10% magnesium oxide. When using the zinc phosphate, the phosphoric acid can be irritating too the pulp, so therefore we would need to use a liner, sealer, or desensitizer too reduce sensitivity. While mixing and setting the zinc phosphate it gives off an exothermic reaction. To dissipate this heat before cementation on a prepared tooth, the cement must be spatulated on a cool, thick, dry glass slab.
The temperature of the slab is an important variable in mixing time for zinc phosphate cement, and the ideal temperature is 68’F. This allows you to work longer on the cement without making the mix to thick. The powder is divided and slowly added and it is critical that the powder be added to the liquid in small increments too dissipate the heat of the chemical action and retards the setting of the cement. This concludes the 5 different types of dental cements and how versatile they are in the dental field.