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Tooth decay and 11 risk factors


Cavities refers to a permanently damaged hole on the hard surface of your teeth. Cavities or tooth decay happens when you frequently eat sugary food and drinks without brushing your teeth daily. 

Cavities are the most common dental disease, especially in children, adolescents, and the elderly. On some occasions, infants may also have decayed teeth.

If cavities get larger and extend into the inside layers of your teeth, they can cause a serious toothache, bleeding gums and cracked teeth. So the best protection for your teeth is regular cleaning and flossing.

Tooth decay
Tooth decay


The symptoms of cavities depend on their extent and location. Tooth decay may not cause any signs at first. When the decayed holes become larger, most common symptoms include: 

  • Toothache even when not biting or chewing
  • Mild or severe discomfort when eating or drinking something sweet, spicy or cold
  • Visible black spots on your teeth surface 
  • Darkening of the teeth

Stages of tooth decay

Tooth decay progresses through several stages, each with its own characteristics and implications for oral health. The initial stage is the formation of dental plaque, a sticky film of bacteria that accumulates on the teeth. If not removed through proper oral hygiene, the bacteria in plaque produce acids that can erode the tooth enamel, leading to the development of cavities.

In the early stage of tooth decay, the enamel begins to break down, resulting in the formation of small, white spots on the tooth surface. As the decay progresses, the enamel becomes weaker and more porous, eventually leading to the formation of a cavity. If left untreated, the decay can reach the dentin layer, causing increased sensitivity and pain.

In the advanced stages, the decay can penetrate the pulp, which contains the nerves and blood vessels, leading to severe pain, infection, and possible tooth loss. Regular dental check-ups and early detection are crucial for identifying and treating tooth decay at its early stages, preventing further damage and preserving dental health.

When to see a dentist

There are no signs at the beginning stages of the cavities, so it’s necessary to make regular check-up appointments. In case you develop a fever or jaw pain, visit a dental clinic.


Cavities develop from tooth decay — a procedure that happens over time. Here’s how tooth decay progresses:

  • Plaque forms. Dental plaque is an invisible coating. It appears when you eat too much sugary food and not brush your teeth well. When sugars aren’t removed from your teeth, bacteria start to feed on them, and plaque is soon formed. Plaque hardens under or above your gum line into tartar (calculus). Tartar makes plaque harder to eliminate and forms a shield for bacteria. 
  • Plaque attacks. The acids in plaque clean off minerals of outer enamel and create tiny gaps in the enamel – the first stage of cavities. Then the bacteria can destroy the next part of your teeth, called dentin. Dentin is softer than enamel so it takes less time for bacteria to destroy this layer. Finally, the bacteria reach the nerve of the tooth occuring sensitivity.
  • Destruction continues. As tooth decay develops, the bacteria and acid move to the pulp, which includes nerves and blood vessels. The swollen and irritated pulp are caused by the bacteria. Because of the lack of space, the nerve becomes pressed, and causes pain with the growth of the swelling. 
Plaque forms
Plaque forms

Risk factors

The following factors can increase risk of getting cavities:

  • Tooth location. Decay most often appears in your back teeth (molars and premolars). These teeth feature several roots, pits and crannies where food usually gets stuck in. Moreover, they’re harder to clean off debrics than front teeth.
  • Certain foods and drinks. Foods that stay on your teeth for a long time — such as milk, ice cream, honey, sugar, soda, dried fruit, cake, cookies — are more likely to cause decay than foods that are easily washed away.
  • Frequent snacking or sipping. When you frequently snack or sip something sweet, the bacteria gain more fuel to multiply and create acids that erode your teeth. Too much soft drink, in particular, creates a constant acid bath over your teeth. 
  • Bedtime infant feeding. Babies are usually used to being given bottles of milk, juice, and other sugary drinks while sleeping. And these liquids remain on their teeth for hours, feeding decay-causing bacteria. It’s often called baby bottle tooth decay. 
  • Inadequate brushing. If you don’t brush your teeth well after eating and drinking, plaque forms fast and the damage can start.
  • Not getting enough fluoride. Fluoride, a naturally occurring mineral, helps prevent cavities and can even back to the earliest stages of tooth decay. Because of its benefits for teeth, fluoride is added to many public water supplies. It’s also a common ingredient in toothpaste and mouth rinses. But bottled water usually does not contain fluoride.
  • Younger or older age. In the United States, cavities are common in 6-8 years old children and teenagers. The elderly also are at higher risk. Over time, teeth can wear down and gums may lower, making teeth more vulnerable. Older adults also may use more medications that increase the risk of tooth decay.
  • Dry mouth. Dry mouth is caused by a lack of saliva, which prevents removing food and plaque from your teeth. Substances found in saliva also help counter the acid produced by bacteria. Some medications or chemotherapy can increase your risk of getting cavities by reducing saliva production.
  • Worn fillings or dental devices. Dental fillings may break down and create a gap. And plaque can grow up quickly underneath dental devices and be hard to remove.
  • Heartburn. Heartburn or gastroesophageal reflux disease (GERD) can cause stomach acid to reverse into your mouth (reflux), washing away the enamel of your teeth and significantly affecting the tooth. This exposes more of the dentin to attack by bacteria, creating tooth decay. Your dentist may advise you to see the doctor to determine whether gastric reflux is the cause of your enamel loss.
  • Eating disorders. Anorexia and bulimia can lead to significant tooth erosion and cavities. Stomach acid from repeated vomiting (purging) washes over the teeth and begins dissolving the enamel. Eating disorders also can interfere with saliva production.


Cavities and tooth decay are so common that you may not be concerned if your child gets cavities. But cavities can develop and last forever, even for children who don’t have their permanent teeth yet.

Most complications include:

  • Pain
  • Tooth abscess
  • Swelling or pus around a tooth
  • Damage or broken teeth
  • Chewing problems
  • Positioning shifts of teeth after tooth loss

In case of cavities and tooth decay get worse:

  • Pain that interferes with daily living
  • Weight loss or nutrition from eating or chewing problems
  • Tooth loss, which may affect your appearance
  • In some cases, a tooth abscess — a pocket of pus that’s caused by bacterial infection — which can lead to more serious or even life-threatening infections


Teeth cleaning at home
Teeth cleaning at home

Good oral and dental hygiene are the best protection against cavities and tooth decay. Here are some recommendations for avoiding cavities:

  • Brush with fluoride toothpaste. Brush your teeth at least twice a day and ideally after every meal, using fluoride toothpaste. To remove debris between your teeth, use dental floss or a water flosser.
  • Rinse your mouth. If your dentist feels you have a high risk of developing cavities, he may recommend that you use a mouth rinse with fluoride.
  • Visit the dentist regularly. Have regular checkups to clean and test the condition of your teeth even when you have nothing wrong with them.
  • Consider dental sealants. A sealant is a protective plastic film applied to the chewing surface of back teeth. It seals off grooves and crannies that collect food, preventing tooth enamel from plaque and acid. The Centers for Disease Control and Prevention (CDC) recommends sealants for all school-age children. Sealants may last for several years, but they need to be checked regularly.
  • Drink some tap water. Most public water supplies have added fluoride, which can greatly prevent tooth decay. If you drink only bottled water, you’ll miss out on fluoride benefits.
  • Avoid frequent snacking and sipping. Whenever you eat or drink beverages other than water, you help your mouth bacteria create acids that can destroy tooth enamel. If you snack or drink throughout the day, your teeth are under constant attack.
  • Eat tooth-healthy foods. There are some foods and drinks that are good for your teeth. Avoid foods that get stuck in grooves and pits of your teeth for long periods, or brush soon after eating them. However, foods such as fresh fruits and vegetables increase saliva flow, and unsweetened coffee, tea and sugar-free gum help wash away meal particles.
  • Consider fluoride treatments. Your dentist may recommend periodic fluoride treatments in case you are getting insufficient fluoride. He may also suggest custom trays that fit over your teeth for the application of prescription fluoride if your risk of tooth decay is very high.
  • Antibacterial treatments. If your state of teeth is vulnerable to cativies, your dentist may recommend certain antibacterial mouthwash or other treatments to kill harmful bacteria in your mouth.
  • Combined treatments. Chewing xylitol-based gum along with prescription fluoride and an antibacterial rinse can significantly decrease  the risk of cavities.


Is tooth decay serious?

Tooth decay is damage to a tooth’s surface, or enamel. It takes place when acids produced by oral bacteria destroy the enamel. Cavities (dental caries), which are holes in your teeth, develop from tooth decay. Without treatment, dental decay can cause discomfort, infection, and even tooth loss.

What do decaying teeth look like?

A white spot on the tooth might be an early sign of dental decay. A darker area or a hole in the tooth may be signs of more severe dental disease. The dentist may also take an X-ray to reveal signs of deterioration and look for soft or sticky spots on the teeth.

Can a cavity go away with brushing?

The hollow will still exist despite all the advantages of brushing. The reality is that there is nothing you can do to stop your cavity from growing. Your cavity will steadily get bigger until it gets to the pulp chamber and produces pain. If the cavity extends to the pulp of the tooth, a root canal will be performed.

What age is normal for tooth decay?

Nearly 90% of adults ages 20 to 64 years have had decay in their teeth, a percentage that has not changed significantly between the 1999–2004 and 2011–2016 NHANES cycles. Older working-age adults 50 to 64 years had the greatest prevalence of decay (96%) in both NHANES cycles.

Is it too late if a cavity hurts?

If your cavity hurts, it’s not too late to save your tooth. Small cavities often don’t hurt too much, but as they become larger, they will begin to. That’s often when you first become aware of them.

Does a black spot on a tooth mean cavity?

Even while black specks can only be surface stains and not always indicate a cavity, there’s really no way to know. Call the dentist as soon as you see a dark spot on a tooth, such as a black or brown mark.


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