Final answer:
Most over-the-counter toothpastes in the U.S. contain fluoride, which helps prevent cavities by strengthening tooth enamel. Toothpastes also typically include abrasives, detergents, and may have remineralization agents and antibacterial components.
Step-by-step explanation:
Most over-the-counter dentifrices, or toothpastes, marketed in the U.S. contain fluoride as the active ingredient to prevent cavities. Fluoride works by becoming incorporated into the tooth enamel and making it more resistant to acid attack from mouth bacteria. Common sources of fluoride in toothpaste include sodium fluoride (NaF), stannous fluoride (SnF₂), olaflur, and sodium monofluorophosphate (Na₂PO3F). Stannous fluoride is considered more effective in reducing dental caries and controlling gingivitis compared to sodium fluoride but can cause more surface stains on teeth.
Toothpaste formulations also commonly include abrasives, which help in physically cleaning the teeth, and detergents, which aid in the removal of plaque and debris. Additionally, toothpastes may contain xylitol, which has been shown to be effective at preventing dental caries in children's permanent teeth. There are also components such as hydroxyapatite nanocrystals and various calcium phosphates included for remineralization, or the reformation of enamel, which can help in repairing early enamel erosion.
Other important ingredients in many toothpaste formulations are antibacterial agents such as triclosan or zinc chloride, which prevent gingivitis, reduce tartar, and combat bad breath.