A luting agent is a cement that your dentist uses to help secure a dental restoration — such as a crown, inlay, onlay or fixed bridge — to your teeth. According to a review in the American Journal of Materials Science and Engineering (AJMSE), dental cements have been used for many years and possess unique chemical properties that help them achieve their purpose, which is to make sure that your carefully crafted dental restorations remain exactly where they belong — in your mouth!
Qualities of an Ideal Luting Agent
Regardless of the type of restoration you're getting or the type of cement your dentist chooses, all luting agents should possess certain properties. According to an article in the Journal of Advanced Medical and Dental Sciences Research, these properties include:
- Low resolution ratios within liquids in the mouth: This means that the cement should not dissolve or "wash out" in the presence of saliva or other liquids typically found in the mouth.
- Biocompatibility: Dental cement should not be toxic to or irritate the dental pulp (nerve) or any other tissues in the mouth.
- Anticavity properties: The cement should help to prevent the formation of decay in the area around the restoration.
- Low viscosity and film thickness: An ideal cement should be very thin when applied so as not to alter the fit of the restoration.
- Sufficient light transparency: In the case of tooth-colored restorations, the cement should not affect the color or aesthetic of the final restoration.
- Resistance: The act of chewing should not dislodge a restoration once it is cemented.
- Heat insulation: The cement should protect the tooth from sensitivity to hot and cold foods and beverages.
- Adequate bond strength: The agent should be able to bond to hard tooth surfaces.
- Long shelf life: A dental professional should be able to store the cement for a period of time without it losing effectiveness.
- Ease of use: The luting agent should allow a dental professional to complete the restoration efficiently, and it should be easy to manipulate.
Types of Luting Agents
There are many types of conventional cements. Most consist of a powder and liquid that create a chemical reaction when mixed together, causing the cement to set. When choosing a dental cement, your dental professional will factor the composition of the restoration it will be used with and the specific requirements that your situation calls for. According to the AJMSE review, some of the more common conventional cements include:
- Zinc phosphate: Zinc phosphate has been in use for more than a century and is regarded as the gold standard for crown and bridge cement. It's also considered a final or permanent cement.
- Polycarboxylate: This can be used as a final or intermediate cement. Polycarboxylate cement has also been used for orthodontic purposes and insulating bases.
- Glass ionomer: Developed in the late 1960s, glass ionomer cement consists of a silicate glass powder and a liquid solution of polyacrylic acid. It can chemically bond to enamel and dentin and also contains fluoride ions to further protect the tooth structure.
- Resin-based cements: This category of dental cements includes resin-modified glass ionomer cement, which is a hybrid formulation of resin and glass ionomer, and self-adhesive cements that are specifically designed for tooth-colored restorations and can be set through a simpler procedure.
The chemistry and handling properties of newer dental cements can be quite complex. However, your dentist can explain to you which luting agent would be best for your needs.