Dental cement is an important part of the long-term stability of crowns and other restorations. Its proper selection and use is critical for both patient safety and clinical success. Other types of dental cement are used for temporary purposes, such as to protect liners and prevent root canal fillings from tooth decay or to support orthodontic appliances. These may contain ingredients such as chlorhexidine to hinder hypersensitivity or fluoride to protect the adhesive interface.
Traditional resin cements are divided into total-etch and self-etch adhesive systems based on their etching mechanism [78]. The former requires multiple steps of application and has a higher risk of contamination, whereas the latter eliminates the phosphoric acid etching step and provides faster polymerization.
Types
Dental cements function as luting materials that fill the space between a restoration fabricated outside the mouth and tooth structure. Upon hardening, they provide mechanical retention for the crown or other restorative material by flowing into irregularities and then bonding with tooth structure.
Glass ionomer and zinc polycarboxylate are common types of luting cements. The former is based on silicate glass and contains fluoride, while the latter has a chemistry that allows it to chemically bond with dentine and enamel.
Resin-based luting cements include those that require etching and application of an adhesive resin to the tooth surface before cementation, as well as self-adhesive resin cements that eliminate the need for this step. These resins use a variety of initiators and packaging to promote their chemical polymerization.
Biocompatibility
Dental cement is used as a luting agent to help secure the dentist’s carefully crafted restorations, such as fillings or crowns, to a tooth. As such, a strong bond between the tooth and cement is necessary to ensure long-term durability and patient comfort.
There are many different types of dental cement available. These include zinc phosphate, zinc polycarboxylate, glass ionomer, resin-modified glass ionomer, and self-etching resin-based cements. These cements are primarily categorized by their chemical composition and applications.
The most common type of dental cement is zinc phosphate, which has been in use since the early 1900s. It is a 2-bottle system that contains a powder mixture and liquid phosphoric acid. This cement is known to be cytotoxic, and has been associated with pulpal hypersensitivity. Additionally, it is reported to be less effective in preventing secondary caries than other cements. Other disadvantages of this type of cement include its short working time and low anticorrosion activity.
Retention
Dental cement is a crucial bonding agent dentists use to secure their patients’ dental restorations such as crowns, inlays, onlays, and fixed bridges. It is specially formulated to ensure that the restorations remain securely attached to the teeth.
Typically, dental cement is available as a powder-liquid that needs to be mixed before being used. The powder is mostly composed of calcium fluoroaluminosilicate glass while the liquid part consists of a water or tartaric acid solution.
There are several types of cements that have been developed to help dentists with their luting procedures. These include glass ionomer cements, resin-modified glass ionomer cements (which are enhanced with composite resin), and self-adhesive cements. Depending on the application, these luting agents can be classified as provisional, semi-permanent, or permanent.
Application
Cement plays an important role in the process of affixing a dental restoration to your teeth. It serves as a luting agent that flows into irregularities between the tooth structure and a restoration fabricated outside of the mouth to provide mechanical retention.
Cements are available in liquid and powder form and should be mixed prior to use in the mouth. They should have a low viscosity and film thickness to allow them to adhere to the tooth surface while not altering their position. They should also be resistant to abrasion, acid, saliva and other liquids found in the mouth.
Resin cements are used to definitively cement indirect restorations like resin bonded bridges and ceramic or indirect composite restorations to the tooth tissue. They contain polyacrylic acid copolymers with itaconic and maleic acids which chemically bond to enamel and dentine through a chelation reaction. Glass ionomer cements (GICs) are used to cement composite restorations to the tooth structure and include calcium fluoroaluminosilicate glass powder with a liquid solution of polyacrylic acid. GICs are often less invasive since they do not require the application of hydrofluoric acid for bonding.