What is a cavity?

What is a cavity?

Cleveland Clinic says a cavity is a hole in a tooth caused by decay: acid from bacteria in plaque erodes the enamel, the hard outer layer. Dentists also call them dental caries. The National Institute of Dental and Craniofacial Research (NIDCR) says tooth decay starts when mouth bacteria make acid that attacks the enamel, and can create a small hole called a cavity. Anyone can get one, though Cleveland Clinic says children are more prone.

How does a cavity form?

NIDCR says bacteria turn sugars and starches from food and drinks into acid, which pulls minerals out of enamel. Repeated acid exposure causes a white spot, an early sign of decay, and at this stage the tooth can still repair itself using minerals from saliva and fluoride. If more minerals are lost than can be restored, a cavity forms. Cleveland Clinic lists risk factors: age, dry mouth, family history, frequent sugary or starchy snacks and radiation therapy to the head or neck.

What are the stages of a cavity?

Cleveland Clinic describes five. First, demineralization: small chalky white spots as enamel minerals break down. Second, enamel decay: spots may turn light brown and holes can appear. Third, dentin decay: spots darken, the tooth becomes sensitive to hot and cold, and decay moves faster because dentin is softer. Fourth, pulp damage: spots turn dark brown or black, the tooth hurts and nearby gums may swell or look red. Fifth, an abscessed tooth: infection causes face or jaw pain and swelling, and a pus pocket can form at the root tip.

What are the symptoms?

Cleveland Clinic lists bad breath or taste, bleeding gums, facial swelling, toothache and tooth sensitivity, and says symptoms may not appear until decay reaches deeper layers. NIDCR says early decay usually causes no symptoms; as it advances it may cause toothache or sensitivity to sweet, hot or cold foods, and infection can cause an abscess, facial swelling and fever. Dentists usually find decay at a routine check-up using visual exams, touch checks or X-rays. Our guide on what cavities look like shows how they can appear.

What do dentists do about cavities?

Cleveland Clinic lists fluoride treatments when decay is just starting, which can repair enamel and may be paired with prescription toothpaste and mouthwash, fillings, where the dentist removes decayed tissue and fills the space with composite, silver amalgam or gold, a root canal for advanced decay, then sealing and often a crown, and extraction when a root canal is not possible, with a bridge or implant to replace the tooth. NIDCR says early decay can be reversed with fluoride applied by a dentist, and cavities are treated by removing the decayed tissue and filling the tooth.

What should you do if you have a cavity?

See a dentist promptly if you have symptoms, says NIDCR. Cleveland Clinic advises seeing a dentist sooner rather than later about a tiny white spot, since it may be an early cavity. A cavity does not heal on its own once a hole has formed, as our guide on whether cavities can be reversed explains. Waiting lets decay reach deeper layers, where treatment is more involved.

What is the role of toothpaste in preventing cavities?

NIDCR says fluoride helps enamel repair itself, can slow decay and can reverse early decay, and that brushing twice a day with fluoride toothpaste is recommended, with other sources including fluoridated tap water, fluoride mouth rinse and fluoride applied by a dentist or hygienist. Cleveland Clinic says fluoride toothpaste is part of daily brushing and that fluoride treatments can repair early enamel damage.

How do you prevent cavities?

Cleveland Clinic says to brush at least twice daily with a soft brush and fluoride toothpaste, floss daily, cut back on sugary and starchy foods and drinks, get check-ups at least twice a year or more often if you are prone to decay, and ask about sealants to protect chewing surfaces. NIDCR adds avoiding frequent snacking, not using tobacco products including smokeless tobacco, and cleaning between teeth daily. Sealants for children's permanent teeth are also recommended by NIDCR.

Questions to ask your dentist

Take these to your check-up.

• Do I have any early decay or white spots?
• Can fluoride reverse it, or do I need a filling?
• How deep is the cavity?
• How can I lower my risk?
• How often should I come for check-ups?

Frequently asked questions