Cavities occur as a result of tooth decay. Tooth decay is the destruction of tooth structure. Tooth decay can affect both the enamel (the outer coating of the tooth) and the dentin layer of the tooth.
Tooth decay occurs when foods containing carbohydrates (sugars and starches) such as breads, cereals, milk, soda, fruits, cakes, or candy are left on the teeth. Bacteria that live in the mouth digest these foods, turning them into acids. The bacteria, acid, food debris, and saliva combine to form plaque, which clings to the teeth. The acids in plaque dissolve the enamel surface of the teeth, creating holes in the teeth called cavities, or caries.
Who Gets Cavities?
Many people think cavities only affect children, but changes that occur with aging make cavities an adult problem too. Recession of the gums (a pulling away of gum tissue from the teeth), often associated with an increased incidence of gingivitis (gum disease), can expose tooth roots to plaque. Also, sugary food cravings in pregnant women can make them more vulnerable to developing cavities.
Decay around the edges of fillings is also common in older adults. Because many older adults lacked the benefits of fluoride and modern preventive dental care when they were growing up, they often have a number of dental fillings. Over the years, these fillings may weaken and can fracture, allowing bacteria to accumulate in the tiny crevices causing tooth decay.
How Do I Know if I Have a Cavity?
Your dentist can discover cavities during your regular dental check-up. The tooth surface feels soft when probed by your dentist with a dental instrument. X-rays can also show cavities before they become visible to the eye.
In advanced stages of tooth decay, you might experience a toothache, especially after consuming sweet, hot, or cold foods or drinks. Other signs of tooth decay are visible pits or holes in the teeth.
How Are Cavities Treated?
Cavities are treated in a number of different ways depending on the extent of tooth decay. If decay is not extensive, the decayed portion of the tooth is removed by drilling and replaced with a filling made of silver alloy, gold, porcelain, or a composite resin. Restorative materials used in fillings are considered safe. Concerns have been raised over the safety of mercury-based, silver amalgams in particular, but the ADA, FDA, and other public health agencies continue to support the safety of this restorative material. Allergies to silver amalgam are rare as are allergies to other restorative materials.
If the decay is extensive and there is limited tooth structure remaining, crowns will be used. If a crown is needed, the decayed or weakened area of the tooth is removed and repaired and a crown is fitted over the remainder of the tooth. Crowns are made from gold, porcelain, or porcelain fused to metal.
If the decay causes the nerve or pulp of the tooth to die, a root canal will be performed. During the procedure, the center of the tooth (including the nerve, blood vessel, and tissue) is removed along with the decayed portions of the tooth. The roots are then filled with a sealing material. If necessary, a crown can be placed over the filled tooth.
Several new treatments are under development. One experimental technique uses fluorescent light to detect the development of cavities long before they can be detected by traditional means, such as x-rays or dental examination. In many cases, if cavities can be detected early, the decay process can be stopped or reversed.