Stages of Tooth Decay

Tooth decay occurs gradually over time and is caused by bacteria that live in dental plaque.  The food we consume contain sugars which the bacteria feed on and convert into acid.  As plaque builds up, these acids begin to erode the tooth enamel leading to decay.

Tooth decay progresses over several stages which will be explored in this article.

Stage One: Demineralization

The outer layer of the tooth is called enamel.  The hardest tissue in the body, enamel is primarily comprised of minerals.  Despite its strength, enamel begins to lose minerals (calcium) and weaken as it is exposed to the acid producing plaque bacteria.  During this initial stage of tooth decay, known as demineralization, patients may see a white spot develop on the tooth where minerals have been lost.  At this stage, it may still be possible to stop or reverse the decay if properly treated.

Stage Two: Enamel Decays

Left untreated, the tooth decay process continues and will further break down the tooth enamel.  At this point, the white spot may darken and take on a brownish color.  Once the enamel is further weakened, small pits or holes may develop in the teeth called cavities.  Typically, cavities will require fillings from a dentist to restore appearance, functionality, and health.

Stage Three: Dentin Decays

As decay progresses through the enamel, the underlying tissue, known as dentin, becomes exposed.  Dentin is not as hard as enamel and given its porous nature, it more prone to acidic damage from plaque.  Decay progresses faster once it penetrates the dentin and because the dentin connects with nerves in the tooth, sensitivity to hot, cold, or air may be experienced once it becomes infected.

Stage Four:  Pulp Damage

The inner layer of the tooth, called the pulp, contains blood vessels and nerves necessary to keep the tooth healthy.  Because the nerves in the pulp provide sensation to the tooth, damage to the pulp can lead to irritation and swelling.  Since there is nowhere within the tooth for the swelling to expand, pressure is placed on the nerves which can lead to discomfort and pain.

Stage Five: Abscess Formation

Once the pulp is affected by tooth decay, bacterial infection can set in.  The infection can increase inflammation within the tooth leading to the formation of a pocket of pus, called an abscess, at the bottom of the tooth.  An abscess can lead to severe pain which may radiate to the jawbone.  Other abscess symptoms can include swelling of the face, jaw, or gums, swollen lymph nodes in the neck, and a fever.  An abscess should be treated promptly as failure to act can allow the infection to spread to the jawbone and other areas of the neck and head.

Stage Six: Tooth Extraction

If tooth decay is left untreated and allowed to spread, the affected tooth will likely need to be removed (extracted) by a dentist.  Because the extracted tooth will leave a gap that adjacent teeth could move into, replacing the missing tooth with a dental bridge or implant may be advisable.

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