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Tooth decay

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What is tooth decay?

Tooth decay, also known as dental decay or dental caries, is when your teeth are eroded by plaque. Over time, the hard protective outer layer of your teeth wears away, exposing the soft and sensitive middle of your teeth to damage.

Although levels of tooth decay have decreased in many places as a result of fluoride in the water supply, it is still a common problem.

Causes

Tooth decay is caused by plaque, which is created when the bacteria in your mouth combine with food particles and saliva. Bacteria in plaque produce acid from carbohydrates found in food, such as sugary foods and drinks. The acid breaks down the hard outer layer of your teeth, eventually damaging the soft middle part.

Risk factors

Risk factors for tooth decay include:

  • Location - tooth decay is most common in the teeth at the back of your mouth because they have more grooves than your front teeth, making them more likely to collect food and harder to keep clean;
  • 'Sticky' food and drink - food that gets stuck on your teeth or between them, such as hard candies, biscuits, milk or ice-cream, causes more damage than food easily washed away by your saliva;
  • Food and drink high in sugar cause the bacteria in plaque to produce more acid, which damages your teeth;
  • Frequent snacking between meals;
  • Inadequate brushing of your teeth;
  • Lack of fluoride - fluoride is a mineral that helps prevent tooth decay and is added to some, but not all, treated water supplies;
  • Age - dental decay is more common in younger or older people;
  • Dry mouth - saliva helps protect your teeth by neutralizing the acid in your mouth. A dry mouth is a sign you are not producing enough saliva;
  • Heartburn - acid reflux can enter your mouth and erode your tooth enamel, and;
  • Eating disorders - both anorexia and bulimia result in recurrent vomiting, which can erode tooth enamel.

Signs and symptoms

Tooth decay often has no symptoms until it becomes advanced, which is why regular visits to your dentist are a good idea. As tooth decay gets worse, symptoms include:

Methods for diagnosis

The majority of cavities resulting from tooth decay are identified during a routine dental check-up. A dental examination can reveal that the surface of your teeth is soft, indicating that the hard outer layer has been worn away. An X-ray of your teeth can also reveal the extent of cavities.

Types of treatment

If caught in the early stages, your dentist can apply a fluoride varnish to your teeth to stop them from decaying further. However, if the outer layer of your teeth has worn away, resulting in a cavity, your dentist will have to remove the decay and create a filling. If the nerves at the roots of any of your teeth have been damaged, you may also require root canal treatment. Any teeth that are so badly damaged they cannot be fixed may need to be removed.

Potential complications

Complications of tooth decay include:

Prognosis

Treatment is more successful and less expensive the earlier tooth decay is caught. If the decay is severe, then teeth may need to be removed.

Prevention

You can help prevent tooth decay by practicing good oral hygiene in the following ways:

Daily brushing of teeth can prevent development of tooth decay.  

11 Most frequently asked questions (FAQs)

What is tooth decay?
Tooth decay is when your teeth become eroded by plaque, which is a combination of bacteria, saliva and food particles. The bacteria in plaque produce acid, which erodes your tooth enamel. Once the hard outer layers of your teeth are eroded, it can affect the soft middle part of your teeth.
What are the symptoms of tooth decay?
There are no symptoms of tooth decay in the early stages, which is why it is important to get regular dental check-ups to catch it early. Symptoms of late-stage tooth decay include toothache and sensitivity, bad breath, visible holes, or grey, brown or black spots on your teeth.
What causes tooth decay?
Tooth decay is caused by plaque that builds up on teeth. Plaque is a mix of bacteria, saliva and food particles. It is particularly damaging when you consume food and drink that is high in sugar, because the sugar causes the bacteria to produce more acid.
How is tooth decay diagnosed?
Tooth decay is usually diagnosed during a routine dental check-up. Your dentist may also take an X-ray of your teeth to detect the extent of cavities.
How is tooth decay treated?
If caught early, tooth decay is treated with a fluoride varnish. If caught late, when the decay has reached the soft middle of your tooth, it may require root canal treatment or tooth extraction.
Can tooth decay be prevented?
You can help reduce the risk of tooth decay by brushing at least twice a day, flossing at least once a day and avoiding between-meals sugary foods and snacks.
What is the outlook for tooth decay?
If caught early, the tooth decay is easily treated with a fluoride varnish, but if left untreated, it can require root canal treatment or a tooth extraction.
Is tooth decay serious?
Tooth decay can be serious. Left untreated, tooth decay can erode the hard outer layer of your teeth and eventually get into the soft middle. If this happens, you may need root canal treatment or the tooth to be extracted.
What increases the chances of developing tooth decay?
Tooth decay happens more often to the teeth at the back of your mouth. It is also more common in people who are young or old, do not brush or floss properly, eat or drink food high in sugar, snack between meals, or have eating disorders.
How common is tooth decay?
Although tooth decay is not as common as it once was, thanks to cavity-fighting fluoride in most treated water supplies, it is still a widespread problem.
What can make tooth decay worse?
The longer tooth decay goes untreated, the worse it gets. Continuing to have sugary food and drink, not brushing your teeth properly, not flossing and not drinking fluoridated water all can make tooth decay worse.

Related topics

Oral hygiene

Clean and healthy teeth and gums are essential for good oral health. Regular brushing and flossing can help prevent tooth decay, gum disease and tooth loss. Together with regular dental check-ups and a healthy, balanced diet, your teeth can and should last a lifetime.

How to clean your teeth

Clean and healthy teeth and gums are essential for good oral health. Regular brushing and flossing can help prevent tooth decay, gum disease and tooth loss. Together with regular dental check-ups and a healthy, balanced diet, your teeth can and should last a lifetime.

Cosmetic dentistry

There are many reasons why a person may want to improve the appearance of their smile, such as having missing, stained or damaged teeth. Cosmetic dentistry encompasses a range of options to make teeth look more attractive, including whitening, repair and replacement.

Dentures

Missing teeth often cause difficulties with chewing and speaking and can affect the appearance of your smile. For this reason, many people choose to replace their missing teeth with dentures, or ‘false teeth’, which are custom-made to fit your mouth.

About this article

Title: Tooth decay

Author: Dr Idan Ben-Barak PhD, MSc, BSc (Med)

First Published: 13 Jul 2015

Last reviewed: 17 Jan 2022

Category: Information on Tooth decay

Average rating: 4.7 out of 5 (1554 votes)

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