Anaheim Pediatric Dentist

What causes dental cavities ?

Dental caries is one of the most common disorders affecting humans [1] [2]. It is the most significant cause of tooth loss in younger people.

The mouth contains a wide variety of bacteria, but only a few specific species of bacteria cause dental caries: Streptococcus mutans and Lactobacilli. These bacteria convert foods especially sugar and starch into lactic acids by fermentation. These acids seep into the tooth and can wear away tooth structure. If conditions in the mouth are favorable, S. mutans and Lactobacilli will continue to thrive and continue to secrete these acids. Bacteria, acid, food debris and saliva combine in the mouth to form a sticky substance called plaque that adheres to the teeth.

Plaque that is not removed from the teeth may mineralize into calculus (formerly known as tartar). Plaque and calculus irritate the gums, resulting in gingivitis. Periodontitis occurs when there is loss of gingival attachment.

Plaque and bacteria begin to accumulate within 20 minutes after eating, the time when most bacterial activity occurs. The acids secreted by S. mutans and Lactobacilli in the plaque dissolve the enamel surface of the tooth. As the bacteria become more prolific, the bacteria will follow the advancing front of acid damage and infect the dentin within the tooth. Left untreated, carious lesions will increase in severity from small discolored stains to actual holes in the tooth (cavities). Cavities are usually painless until they grow very large inside the internal structures of the tooth (the dentin and the pulp at the core) and can kill the nerve and disrupt the blood vessels in the tooth. If left untreated, complications may occur such as infection of the pulp or abcesses within the jaw.

Dietary sugars and starches (carbohydrates) increase the risk of tooth decay. The type of carbohydrate and the timing and frequency of ingestion are more important than the amount. Sticky foods are more harmful than nonsticky foods because they remain on the surface of the teeth. Frequent snacking increases the time that acids are in contact with the surface of the tooth.