Are Cavities Contagious? Can You Catch a Cavity?

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Dental cavities- are they contagious like a common cold? Can you catch a cavity? Yes and no.

Are Cavities Contagious? Can You Catch a Cavity?

When we eat or drink, two processes take place in our mouths, side by side.

The process involves a balance between bacteria weakening enamel by producing acids (demineralization) and saliva providing minerals(remineralization). Whenever this balance is disturbed, there is a risk of dental decay to develop.

Does a tooth cavity spread?

WHO has now classified caries as a non-communicable disease. While this technically makes it non-contagious, the bacteria that cause it can be spread through saliva, so there is a risk of spread from one person to another when sharing utensils, sharing drinks, sharing toothbrushes, or kissing.

Tooth decay or dental caries, is one of the most common global diseases that causes cavities. Dental decay occurs over time which results in cavities. If left untreated, cavities can get larger and affect deeper layers of your teeth, eventually resulting in permanent tooth loss

A lot of factors can contribute to developing caries, such as oral bacteria, poor oral hygiene, consuming lots of sugar, little to no fluoride exposure ( fluoride prevents tooth decay by making the enamel more resistant to the action of acids.), tooth position, access to oral health care, socioeconomic status, and smoking.

Factors Contributing to Cavity Transmission

Oral bacteria and their role in cavity development

How do we get cavities? When we eat, the bacteria in our mouths feed on sugar from leftover food particles and process it into acid.

Plaque on Teeth

It attacks the hard surface of your teeth (enamel). This exposure to acid over a long period (months or even years), wears down the enamel, creating a hole – a cavity.

The impact of diet and lifestyle on cavity transmission

Caries-causing bacteria thrive in a highly acidic environment.

This means that any lifestyle habits such as smoking that dries out the mouth by reducing salivary production, excess sugar intake that provides bacteria a favorable environment to thrive, and food and acidic beverages, that eventually wear away the enamel, can aid these harmful bacteria.

This is why a well-balanced diet is essential for a healthy mouth.

The role of genetics in cavity susceptibility

While parents don’t directly pass down their dental cavities, some genetic conditions can make the children more prone to getting caries and other dental issues.

Pregnant mothers can pass cavity-causing bacteria to their babies in the womb. Genetics account for up to 65 percent of tooth decay or other dental predispositions . Some factors can make the chances of cavities or other dental issues, genetic, such as

  • Enamel strength: Enamel is the hardest layer of your teeth. Strong enamel means better absorption of vital minerals like calcium and fluoride, keeping teeth strong and resisting bacterial demineralization. In some genetic conditions where the enamel is structurally weak or thin, there is more chance of developing caries because there is no extra layer of protection.
  • Shape of teeth: Everyone’s teeth vary by shape, size, and alignment. If the tooth structure is such that there are deep pits, fissures, or grooves, there is more chance of food getting trapped there and it’s also difficult to clean. This makes it more prone to developing dental caries.
  • Teeth alignment: Teeth that are crooked, overlapped or overcrowded with tight contacts, make it harder for the brush and floss to reach these areas. food particles get trapped here and increase the risk of developing caries.
  • Saliva: Saliva can help prevent cavities by metabolizing minerals. Some genetic conditions reduce the amount of salivary production, which can aid the bacteria causing cavities in your mouth.
  • Immune system: If your immune system is compromised, it won’t be able to effectively protect your teeth against harmful bacteria, leaving them more prone to develop decay.

Preventing the Spread of Cavities

Importance of good oral hygiene

A healthy mouth is a gateway to a healthy body. Good oral hygiene prevents bad breath, dental cavities, gum issues, and tooth loss amongst other problems.

Brushing Flossing

Good oral health can affect both your physical and mental well-being. It impacts your ability to enjoy your favorite foods, how you speak, and your interpersonal relations.

A healthy smile adds to your appearance and confidence. A diseased mouth on the other hand can affect the rest of your body and be a contributing factor to several other disease conditions.

Dietary habits for cavity prevention

Hydrate! Drinking water is the simplest and most inexpensive way to keep your gums and teeth healthy. Water washes away the food particles & bacteria to prevent plaque buildup as well as prevent dry mouth.

Eat food that stimulates salivary secretion, as it has a protective effect against caries, e.g., hard cheeses, peanuts, wholegrain foods, and sugar-free chewing gum.[9]

Avoid sugary and sticky foods. A diet rich in fresh vegetables, fruits, and wholegrain starches and low in added sugars and fat prevents chronic diseases associated with diet, including oral conditions like dental caries, periodontal infections, and oral problems.

Good oral hygiene habits can help you achieve the best oral health. These practices include

  • Brushing twice a day, every day for at least 2 minutes
  • Floss daily 
  • Eat a well-balanced, healthy diet to provide the necessary nutrients (vitamins A and C, in particular) to prevent gum disease.
  • Avoid cigarettes and smokeless tobacco, which are known contributors to gum disease and oral cancer.
  • Regular dentist checkups for cleanings and exams, for the prevention & early detection of dental problems

Professional dental care and regular checkups

Regular dental checkups are important for early detection and prevention of dental problems.

At your routine checkup, your dentist will examine your teeth, gums, and mouth, discuss your health, address any issues, provide advice on diet, smoking, alcohol use, and teeth-cleaning habits, and schedule a next visit.


So while caries are not technically contagious, the bacteria that cause them can still spread through saliva. The good news is that it doesn’t guarantee you a cavity, your diet and oral hygiene habits play a major role in aiding or preventing the decay in the first place.

FAQ: Cavities and Your Smile

Can cavities spread from person to person?

Can cavities spread from person to person?

Caries-causing bacteria can spread through saliva. So while it’s not guaranteed, kissing, and sharing utensils or toothbrushes carries a transmission risk.

Do tooth cavities spread?

If left untreated, cavities can spread deeply into the teeth and can even result in eventual tooth loss.

Can babies get cavities?

Children of any age can get cavities but they form faster in baby teeth than in adult (permanent) teeth. They can start to develop as soon as baby teeth come in, usually between 6 months to one year of age.

Can I kiss my boyfriend/girlfriend without worrying about cavities?

Sharing a kiss with good oral hygiene on both sides is generally safe. However, consistent good oral hygiene habits are key for everyone to prevent getting cavities.

If I kiss my child, will they get cavities from me?

Not necessarily! While you can share cavity-causing bacteria through saliva, good oral hygiene habits for both you and your child can prevent them from causing problems.

Are children more susceptible to getting cavities from their parents?

Young children are more susceptible to cavity-causing bacteria transferred from parents through saliva, both before birth and after through close contact or shared utensils.

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