Composite Resins are used mainly in dental restorative procedures and are typically acrylic-based to which a glass or a natural silica filter has been added. Composite resin is a tooth-colored plastic mixture filled with glass (silicon dioxide).
Composite resin was introduced by 1960; dental composites were not strong enough to resist the pressure and wear generated by the back teeth, so dental composites were confined to the front teeth. Since then, composites have been considerably improved and can be effectively placed in the back teeth as well. Composite resin is also used for cosmetic improvements of the smile by altering the color of the teeth or reforming disfigured teeth.
The preparation of composite resin, which is done by the dentist, begins with placing the composite layers using a light specially made to harden each layer. When the process is done, the dentist will mold the composite to fit the tooth. After this, the dentist polishes the composite to prevent staining and early wear. This preparation takes about 10 to 20 minutes longer to place a composite than a silver filling. However, the process of the placement time may take longer depending on the location and size of the cavity.
Composites prices range from about one-and-a-half to two times the price of a silver filling. With the patient paying the difference, majority of the dental insurance plans cover the cost of the composite up to the cost of a silver filling. Insurance companies are more likely to increase the coverage of composites, as composites continue to improve.
Since a dentist can mix shades to produce a color nearly identical to the actual tooth, the major advantage of composites is esthetics. To support the remaining tooth structure, composites bond to the tooth which helps to avoid breakage and protect the tooth from excessive temperature changes.
The disadvantage of composite resin consists of experiencing post-operative sensitivity. If the patient drinks coffee, tea or other staining food, the shade of the composite can slightly change. To avoid the color from changing, the dentist can put a clear plastic coating over the composite. Although composites hold up as well in small cavities, they have tendencies to wear out sooner than silver fillings in larger cavities.
Comparable to silver filings, composite resin can last from 7 to 10 years, except in very large restorations, where silver filings last longer than composites.