Toothpaste is a paste or gel dentifrice used with a toothbrush as an accessory to clean and maintain the aesthetics and health of teeth. Toothpaste is used to promote oral hygiene: it serves as an abrasive that aids in removing the dental plaque and food from the teeth, assists in suppressing halitosis, and delivers active ingredients (most commonly fluoride) to help prevent tooth decay (dental caries) and gum disease (gingivitis). Salt and sodium bicarbonate (baking soda) are among materials that can be substituted for commercial toothpaste. Toothpaste is not intended to be swallowed due to the fluoride content, but is generally not very harmful if accidentally swallowed in small amounts; however, one should seek medical attention after swallowing abnormally large amounts.
In addition to 20–42% water, toothpastes are derived from a variety of components, the three main ones being abrasives, fluoride, and detergents.
Abrasives constitute at least 50% of a typical toothpaste. These insoluble particles help remove plaque from the teeth. The removal of plaque and calculus helps minimize cavities and periodontal disease. Representative abrasives include particles of aluminum hydroxide (Al(OH)3), calcium carbonate (CaCO3), various calcium hydrogen phosphates, various silicas and zeolites, and hydroxyapatite (Ca5(PO4)3OH).
Abrasives, like the dental polishing agents used in dentists' offices, also cause a small amount of enamel erosion which is termed "polishing" action. Some brands contain powdered white mica, which acts as a mild abrasive, and also adds a cosmetically pleasing glittery shimmer to the paste. The polishing of teeth removes stains from tooth surfaces, but has not been shown to improve dental health over and above the effects of the removal of plaque and calculus.
The abrasive effect of toothpaste is indicated by its RDA value. Too high RDA values should be considered critical, and some dentists recommend toothpaste of …