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Are Cavities Contagious?

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A woman holding the side of her face due to cavity pain

Without proper dental care, you may experience a cavity. Cavities can seem like nothing, but decay can significantly affect the functionality of your tooth. Cavities develop due to bacteria, so are they contagious? 

Continue reading to learn more about cavities, including how they develop and if they’re contagious. 

What Are Cavities? 

Cavities, also known as tooth decay, are permanently damaged areas of your teeth. Bacteria break through the hard surface of your teeth (enamel), creating small holes. Cavities are one of the most common dental problems, especially in children. 

Tooth decay can seem insignificant at first, but it worsens with time. Cavities grow and eventually affect the inner layers of your tooth. Unless treated, tooth decay can lead to severe toothache, infection, or even tooth loss. 

You typically feel pain as a cavity worsens, but you may have no symptoms at first. Regular dental checkups are the best way to catch early signs of a cavity. 

Cavity Symptoms

The symptoms of a cavity may vary depending on its severity and location. As a cavity develops, you may experience: 

  • Brown, black, or white staining on the tooth’s surface
  • Mild to sharp pain when eating or drinking something hot, cold, or sweet
  • Pain when biting down
  • Toothache
  • Tooth sensitivity
  • Visible holes or pits in your tooth
A plastic tooth with a cavity on it, sitting on top of a wooden toothbrush

What Causes Cavities? 

Cavities occur due to plaque formation. Plaque is a clear coating created when bacteria feed on sugars and starches left on your teeth.

Plaque hardens when left unaddressed, becoming harder to remove. The acids in plaque erode your tooth enamel and dig deeper into your tooth. 

This process can take months to years, depending on your oral health, enamel health, and the cavity’s location

Tooth decay typically progresses through 5 stages as it damages your teeth: 

  • Initial demineralization: Cavities begin when acids from plaque damage the enamel, causing the loss of the minerals that make up this tissue—you may notice a white spot form on the tooth.
  • Enamel decay: As decay continues, the enamel breaks down further & small holes begin to form—these holes are cavities.
  • Dentin decay: Dentin is the tissue underneath the enamel that holds tubes leading to your tooth’s nerves—you may begin to experience sensitivity when having hot or cold foods & drinks.
  • Pulp damage: Your dental pulp is the inner area of your tooth, containing the nerves & blood vessels needed to keep your tooth healthy—damage to the pulp can lead to swelling & pain.
  • Abscess: With time, bacteria can enter your pulp & cause an infection known as an abscess.

The Danger of Cavities 

If cavities are left unaddressed, you risk developing a tooth abscess. An abscess is a dental emergency requiring treatment as soon as possible. Depending on its severity, your dentist may have to drain the abscess, pull your tooth, perform a root canal, or prescribe antibiotics. 

Never ignores signs of an abscess, such as a toothache, fever, swelling in the face, pressure sensitivity, or sensitivity to hot or cold temperatures. 

Are Cavities Contagious? 

Believe it or not, cavities are an infectious, transmissible disease. The main bacteria promoting tooth decay is streptococcus mutans, a naturally occurring bacteria in your mouth that can build up on your teeth and spread. This bacteria first appears in early childhood when a child first develops teeth. 

2016 research shows how streptococcus mutans can spread from person to person. A study of mothers and their babies determined whether or not children could have streptococcus mutans in their mouths before they developed teeth. 

Children typically develop teeth around 8 months old, but 30% of the children in the study had signs of this bacteria at 3 months old. At 6 months old, approximately 60% of children showed the presence of streptococcus mutans. 

The study found that this bacteria spread through saliva, including sharing food and utensils and other close-contact habits like kissing.

Don’t Ignore Cavities 

While cavities can significantly affect your dental health, your dentist can help. They can identify early signs of a cavity during your regular dental exams and determine the severity of your tooth decay. Restorative dental care can help treat your cavity, restoring functionality to your tooth. 

Some common ways to address cavities are fillings and crowns. The best treatment depends on the severity of your tooth decay, but both can help address damaged teeth: 

  • Fillings: Fillings can directly go into the cavity, helping strengthen the tooth & restore functionality. Several types of fillings exist, including metal & tooth-coloured fillings.
  • Crowns: A crown is a cap used to cover a damaged or decayed tooth, helping restore functionality & protect the tooth from further damage.

While your dentist has several ways to deal with cavities, it’s best to treat them early. Don’t ignore signs of tooth decay—you can help protect your dental health. You may not notice signs of a cavity at first, but your dentist can during your dental exam. 

Contact your dentist if you’re experiencing cavity symptoms or if it’s time for a dental exam. 

Written by Judith Kivinen

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