Tooth Decay: Symptoms, Causes, Diagnosis, and Treatment Options

Tooth Decay: Symptoms, Causes, Diagnosis, and Treatment Options


Tooth decay occurs when the bacteria that are present in your mouth act on starches and sugars in the mouth to produce acid, which progressively erodes the enamel of youth teeth. Eating and drinking foods that contain some acid also exposes your teeth to the acid, which slowly eats away the teeth’s outer layer.

Tooth decay leads to loss of the white and shiny appearance of the teeth. And when not treated, tooth decay can lead to cavities or holes in the teeth. These holes can grow and damage the entire tooth.

Given that everyone is at risk of tooth decay because of eating foods that contain starch or sugar, it is important to get information about the condition’s causes and risk factors, symptoms, diagnosis, and treatment options.


There are various symptoms that you can use to tell whether you have tooth decay. These include:

  • Continuous or occasional toothache: If your teeth are decaying, you may have a continuous or occasional toothache. The pain may be more pronounced when you bite or chew food and when you brush your teeth.

  • Bad breath and taste in the mouth: Bad breath mostly occurs due to the plaque deposits that are present on the decaying tooth. You may also feel a change in the taste.

  • Cavities or holes in your teeth: You may notice holes called cavities in the section of the tooth that is decaying. Cavities are caused by various factors including the action of bacteria that are present in the mouth and on teeth surfaces.

  • Staining or discoloration of your teeth: You may also see grey, brown or black stains on your teeth. Discoloration occurs as minerals in the tooth’s enamel are slowly eaten away.

  • Tooth sensitivity: If the decay has reached the tooth’s dentin, you may experience a twinge or a sharp pain each time you consume a food that is hot, cold or sweet or while brushing. You may also experience some pain when you are out in the cold.

Causes and risk factors

Main causes/risk factors

Tooth decay is caused by many factors, the most notable ones being the consumption of starch, sugary, or acidic foods and drinks, and failure to practice proper oral hygiene by flossing and brushing every day.

When you consume any food that contains carbohydrates, starch and sugar particles get trapped between your teeth. These compounds are then acted on by the bacteria that reside in your mouth, which digest them to produce acid and other compounds. The acid that is released starts to react with the minerals that are present in your teeth’ enamel.

According to Procter and Gamble, a company that manufactures dental care products, sugar works together with plaque to make the enamel weaker and leave you susceptible to tooth decay. Procter and Gamble also notes that every time you eat a sugary food, your teeth become vulnerable to acid attacks over the next 20 minutes. This means that if you snack frequently, you significantly increase the risk of having decayed teeth.

If you do not brush your teeth every day, the teeth will have notable deposits of plaque. Plaque provides a good habitat for bacteria to thrive and continue acting on starches and sugars that are present in the mouth at any given time, leading to further tooth decay

Other risk factors

Apart from the consumption of starchy or sugary goods and failure to exercise good oral hygiene, which are the main causes of tooth decay, there are other factors that increase the risk of the condition. The risk factors include:

  • Dry mouth – Lack of saliva means that food and plaque are not washed away from the mouth. If there is inadequate saliva, the ability to counter the action of acids on teeth is also reduced.

  • Inadequate fluoride – Fluoride is one of the elements that strengthen teeth and protect them from being eroded by acids. Inadequate fluoride makes the teeth’s enamel susceptible to being eaten away.

  • Tooth location – Tooth decay often starts in the back teeth (premolars and molars). This is because these teeth have many pits, groves, roots and crannies. This makes them harder to clean.

  • Disorders like acid reflux and bulimia – These cause stomach acid to flow into the mouth, thus increasing the risk of tooth decay.


When you visit a dentist for a tooth decay diagnosis, the dentist will ask you about sensitivity and pain. The dentist will also do the following:  

  • Examine your teeth and mouth

  • Probe your teeth using dental equipment to check for areas that are soft

  • Take a dental X-ray, which can reveal the extent of the decay and cavities.

Treatment options

Treatments for tooth decay vary depending on the extent of the decay and cavities that the dentist has diagnosed. If the problem is not severe, the dentist may only apply fluoride gel to the area to help revitalize the tooth.

For cavities, the dentist may recommend filling of the tooth to seal the hole, or root canal treatment in case the tooth’s nerves and pulp have been damaged. Filling is appropriate where the decay has not reached the tooth’s pulp. A root canal procedure involves the dentist removing the pulp and nerves in the root of the tooth, cleaning the tooth, and then sealing it.

If the tooth is so badly spoiled, the dentist may recommend its removal and replacement with a structure such as a dental implant, bridge or partial denture.

It is also important to visit your dentist regularly because this will help you get tips on how to prevent further tooth decay. Regular dental visits can also lead to early detection and treatment of tooth decay.


Tooth decay makes teeth lose their white and shiny look. You should be on the lookout for any symptoms of the disease and avoid habits that can cause the condition, such as eating sugary foods and failing to brush and floss daily. You also need to visit your dentist regularly for checkups so that if you have any symptoms of tooth decay, you can get treatment before your teeth develop severe cavities.

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