Dental cavities are a common, chronic and global health problem that affects people of all ages. Worldwide, 2.43 billion people (36% of population) suffer from cavities.
Every 1 in 3 individuals is expected to have one or more cavities, filled or restored teeth in their mouth. Also, children of mothers with untreated cavities are twice likely to get cavities than the ones without cavities. Moreover, a cavity is a bacterial infection and is packed with nasty decay-causing bacteria. All these factors raise a question: are cavities contagious, like other bacterial infections? The answer is somewhat complex and requires an understanding of the causes behind cavity formation, which are multifactorial.
Let’s get strated:
What are cavities?
Dental cavity is a diet-related bacterial infection, also known as dental caries or tooth decay. The infection weakens and destroys the hard tooth structure, leaving a black discoloration or a hole in a tooth.
What causes cavities?
The cavities thrive in a particular environment and several factors play a role in their initiation and progression. The following factors are critical for their development:
Primary factors
Dental plaque and bacteria
Dental plaque is essential for cavity formation. It is a whitish-yellow film of microorganisms attached to the tooth surface and it begins to deposit a few hours after toothbrushing.
Our mouth contains 200-300 different bacterial species, including all the good and bad bacteria. In a healthy oral environment, they live in symbiosis. However, our dietary habits determine the dominant bacterial colonies in the mouth and, hence, the ability to develop disease.
Among the resident oral bacteria, Streptococcus mutans (S. mutans) accounts for large colonies in the mouth and is predominantly responsible for initiating dental cavities. Lactobacilli is the second most common culprit bacteria contributing to cavities.
S. mutans can adhere to hard tooth structure, create a slimy environment, and multiply to establish permanent colonies. Also, it can metabolize simple sugars into lactic acid, which can cause enamel demineralization.
Negligence towards toothbrushing and flossing allows plaque to build up on the teeth. Over time, the plaque thickens and diversifies its bacterial colonies. Moreover, frequent episodes of lactic production erode and weaken the enamel and pave the way for bacteria to enter the tooth.
Read more: Why do my teeth feel sticky?
Diet
Refined and sugary foods and drinks increases the risk of cavities. Cavity-causing bacteria thrive on white sugar to grow into large colonies. However, they can’t metabolize the complex carbohydrates such as whole wheat cereals and aren’t associated with dental cavities.
People who consume refined foods high in sugar are more prone to develop cavities than the ones who consume a high fiber, high protein diet, even if they keep their mouths clean. Toothbrushing and flossing remove more than 80% of the plaque, but plaque is inevitably left behind in most people. So, diet management is essential, along with good oral hygiene.
Time
Frequent epidoses of
Secondary factors:
Dry Mouth
Reduced saliva flow, frequently associated with certain medications or medical conditions, can contribute to cavities. Saliva is rich in phosphate and bicarbonate ions and helps neutralize acids and remineralize tooth enamel. It also forms a protective layer on the tooth and washes away bacteria through swallowing.
An average person swallows 1-2 times per minute and 500-700 times a day. Frequent swallowing reduces bacterial load from the mouth and naturally fights against cavity formation.
Genetics
Some individuals are more genetically predisposed to cavities, even with good oral hygiene.
Are cavities contagious?
No, cavities themselves are not contagious. However, the nasty bugs, mainly Streptococcus mutans, that contribute to tooth decay can spread from one person to another through activities like sharing utensils, kissing, or close contact, increasing the risk of cavity formation.
It is recommended to have 10,000 CFU (colony forming unit) per ml of saliva of Streptococcus mutans in the mouth to decrease the bacterial load and their transmission. It can be done by maintaining good oral hygiene.
Colony Forming Units CFU S. mutans/ml saliva
- People with good oral hygiene (class 0-1) <100,000
- People with moderate oral hygiene (class 2) 100,000< CFU/ml <1,000,000
- People with poor oral hygiene (Class 3) >1,000,000 CFU
Are cavities contagious in adults?
Cavities, per se, are not contagious in adults. However, oral bacteria can be transmitted through salivary contact. The odds of spreading cavities in adults through salivary contact are directly proportional to personal oral hygiene and untreated cavities.
For instance, mothers with several dental caries are more prone to transfer cavity-causing bacteria to their babies. Baby mouth’s are sterile at birth and acquire oral bacteria as they grow. A high sugar diet feeds the cavity-causing bugs, and the incidence of developing cavities increases several times if the nasty decay-causing bugs over-populate the mouth. Therefore, if you often get cavities or have several untreated decayed teeth in your mouth, never put your child’s utensil back in your child’s mouth after licking it.
Read more: Cavities: Causes, Symptoms, Prevention, and Treatment
Can cavities spread to other teeth?
Cavities don’t spread from one tooth to another like an infection. However, the bacteria that cause cavities can affect adjacent teeth if there are any plaque deposits. Plaque deposition initiates tooth decay, and any tooth with plaque can potentially develop a cavity. The plaque bacteria produce acids that erode tooth enamel and initiate a cavity.
Frequently, proximal caries — a cavity on the side of the tooth — soon spread to the adjacent tooth if left untreated. Proximal cavities are often detected late due to poor visibility. Often, one lesion is larger than the other upon diagnosis. A larger defect requires a deep filling or root canal treatment, and the shallow cavity is restored with a filling or fluoride treatment.
Furthermore, plaque deposits anywhere on the teeth can initiate tooth decay if there are enormous colonies of nasty bugs in the mouth and ample consumption of simple sugars in the diet.
Read more: Cavities Between Teeth: Why They Happen Even If You Brush Every Day
How fast do cavities spread?
The rate at which cavities spread may vary. In some individuals, cavities progress slowly and take several months or years to reach the pulp, whereas others show rapid progression in cavities. The rate of cavity spread is linked to lifestyle, colonies of bugs present and oral hygiene.
Rapid cavity development and progression are frequently seen after head and neck radiation. The radiation causes atrophy (shrinkage) of the salivary glands resulting in reduced saliva production. The reduced salivary flow leads to more food sticking to the teeth, decreased clearance of food debris after a meal and increased bacterial adherence to the teeth.
The thick, stringy saliva produced from the shrunken salivary glands fails to perform its function: washing away food debris, bacteria and keeping the oral surfaces moist. Therefore, these patients develop numerous, rapidly progressing tooth cavities.
Other factors that lead to multiple, and rapidly progressing cavities are bad oral hygiene, high sugar diet and intake of drugs causing dry mouth.
Regular dental check-ups can help detect and address cavities early, preventing further spread and damage. Patients are also advised to take artificial saliva to prevent the side effects associated with dry mouth.
Can cavities spread to gums?
Yes, untreated, deep cavity infection can spread to the gums and can lead to periodontal (gum) problems. A cavity begins with enamel erosion and then spreads to dentin and pulp.
Untreated pulpitis (pulpal infection) can infect gums through tiny openings in the teeth. The gums around the infected tooth appear red, swollen and painful. Occasionally, pus discharge may be seen in the gums. This form of gum disease is localized and is seen around single tooth.
Generally, it is not the cavity spread that affects gum, but it’s the plaque accumulation on the teeth that gives rise to cavities and gum disease.
Read more: 8 Signs of wisdom teeth coming in
Can cavities spread to your brain?
No, cavities do not spread to the brain in most cases. A dental cavity is a localized dental issue that affects teeth. However, in rare cases (0.3-0.9% in 100,000 cases), a severe dental abscess from the upper molar can spread to the brain through the maxillary sinus or blood circulation. The spreading infection of the brain presents as consistent fever, headache, and neurological problems.
Read more: Does lysine stop viral shedding and prevent cold sores?
Can baby cavities spread to other teeth?
Yes, baby cavities, also known as early childhood caries or baby bottle tooth decay, can spread to other teeth if left untreated. The interproximal cavities are most likely to affect the neighboring tooth. The baby cavities progress rapidly and soon become painful because of the thin enamel and dentin and wider pulp chambers.
The decay spreads faster and involves several teeth in the mouth if the child has a habit of sleeping with a milk bottle. The lactose in milk is a fermentable sugar and is metabolized by oral bateria into acid. Decreased salivation during sleep may also facilitate the initiation of cavities often involving more than one teeth. It’s crucial to address cavities in baby teeth promptly, as they serve an important role in jaw development, and acts maintaining space for adult teeth.
Read more: An alternate to root canal treatment
How to stop the spread of cavities?
You can prevent the spread of cavities to by following the following measures: \
- Regular brushing and flossing decrease the colonies of disease causing bacteria in the mouth.
- Increased consumption of high fiber diet flourishes the growth of good bacteria and inhibits the proliferation of cavity-causing bacteria.
- Avoid sharing utensils or toothbrushes especially with children to minimize the transmission of cavity-causing bacteria.
- Visit the dentist regularly for check-ups and scaling and polishing of the teeth. Early detection and intervention of cavties save time, money and further damage to the teeth.
Conclusion
Cavities themselves are not contagious, but the bacteria that contribute to tooth decay can be transmitted through activities like sharing utensils or close contact. Practicing good oral hygiene and a high fiber diet help minimize the spread of these bacteria and reduces the risk of developing cavities.