When the enamel on the surfaces of teeth begins to break down, pockets of decay from on the teeth. Tooth decay occurs when bacteria and plaque mix with metabolizing sugary and starchy foods, forming damaging acid that eats away at the tooth’s enamel. In its earliest stages, tooth decay may be able to be effectively treated with proper oral care and regular professional dental cleanings. While your dentist can diagnose the extent of your tooth decay in order to determine the appropriate course of treatment, it is helpful to understand these stages of decay.

In its first stage, tooth decay appears as chalky white spots of the surface of the teeth. These spots are caused by the depletion of calcium and other minerals in the teeth, combined with the accumulation of plaque. Bacteria in plaque metabolizes with sugars, forming acids that deteriorate the tooth enamel and deplete the minerals that make up enamel. In stage one, tooth decay can often still be reversed with the proper treatment. Treatment at this stage may include appropriate brushing practices and topical fluoride and should be discussed with your dentist.

At stage two, the tooth’s natural remineralization process has slowed, and healthy enamel cannot rebuild quickly enough to protect the surface beneath the tooth’s enamel. This allows a lesion to form in the tooth just beneath the enamel. As decay continues to wear away at the enamel, this can lead to cracks or fractures in the surface of the teeth; if your teeth crack, seek immediate dental care.

Stage three of tooth decay is also called dentin decay. Dentin is the layer of the tooth that lies beneath the tooth’s enamel, connecting the enamel and the pulp. Once acids and bacteria have sufficiently eroded the enamel, the lesion that has formed on the tooth’s surface can reach the dentin. Dentin is rich in blood vessels, and dentin decay is usually accompanied by sharp pain in the affected tooth. Once the enamel has sufficiently demineralized, the enamel collapses completely and a cavity forms. At this point, a filling is almost certainly necessary to restore the tooth.

Stage four of tooth decay involves the tooth’s pulp. Pulp is the center portion of the tooth and is made up of living tissues, cells, and nerve endings. When a tooth’s pulp becomes infected, the pus that forms kills off the blood vessels and the nerves in the tooth, causing constant pain. When the pulp of a tooth has become infected, the most common treatment is root canal therapy. In its most basic form, root canal therapy entails cleaning infected pulp out of the center of the tooth and treating the inside of the tooth to prevent recurrence of infection.

The fifth stage of tooth decay occurs when an abscess forms. If the infection in a tooth’s pulp reaches the tip of the tooth’s root, the infection can spread into the bones that support the tooth, causing an abscess, as well as a significant amount of pain. The infection can cause the tongue and gums to swell, which may increase risk for other diseases and which can affect your speech and your ability to eat and drink. Oral surgery is almost always necessary when an abscess is present.

In the final stage of decay, the affected tooth itself is damaged beyond repair and must be extracted, if it has not already fallen out on its own. Tooth decay is an entirely manageable issue and can easily be prevented. The most important preventative practice is regular, effective oral hygiene. Use a soft-bristled toothbrush and fluoride toothpaste to brush twice daily, and be sure to floss daily to clean between the teeth and at the gumline. Avoid between-meal snacking and try to reduce your intake of sugary or starchy foods and drinks, and make sure to drink plenty of water, which encourages the production of saliva and helps keep enamel nourished and the mouth clean. Regular checkups and professional dental cleanings are also important parts of an effective tooth-decay prevention regimen

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