What Bacteria Causes Dental Caries? – Top Trends – 2023

People often wonder what bacteria causes dental caries. ‘An apple a day keeps the doctor away’ is a popular saying that most people have heard at some point in their lives. However, we have discovered over time that an apple a day may require you to see a dentist sooner than expected.

Due to the presence of sugar moiety in apples, human teeth are just at risk as if candy or juices are consumed instead. Dental caries is found when the bacteria responsible for these anomalies are present on the tooth surface and have access to fermentable sugars, which are carbohydrates.

They often have a significant amount of time to pass between proper dental hygiene practices.

What are Dental Caries?

Daily hygiene and dental care concept for dental caries explained by a dentist

Dental caries is a disease also referred to as cavities or tooth decay. It is caused by certain bacteria that live and grows in the mouth; they thrive on sugars and refined carbohydrates and produce acids as a by-product.

The acids attach to the enamel first, the hard outer layer of your tooth. The acids eventually penetrate this layer into the softer mineral layer within the tooth (dentin). If left untreated, tooth decay can destroy a large segment of the tooth, infecting the nerve pulp at the center of the tooth.

In elderly adults, exposed root surfaces are prone to be a risk factor for dental caries; these caries are highly preventable with many contributing factors.

what bacteria causes dental caries

What Bacteria Causes Dental caries?

The bacteria that are proven to be responsible for causing dental caries are ‘Streptococcus mutants and ‘Lactobacillus’ These bacteria flourish and grow in the biofilm or tooth plaque that should be gotten rid of during proper dental hygiene.

In the presence of dietary carbohydrates, these bacteria found in plaques create high levels of lactic acid through the fermentation of sugars. This acid further breaks down the enamel that protects the nerve, root, and pulp; this eventually causes dental caries.

  • Lactobacillus – This bacterium hides in the nook and crannies of one’s teeth. This environment is perfect for their growth because it is also where food enters when you are chewing. Brushing into all the crevices is necessary because these bacteria can cause tooth decay and caries, especially in young people under age 12.
  • Streptococcus – While the lactobacillus is hanging out in the cavities of the teeth, the other six various types of streptococci work on the smooth surface and sides. Flossing is essential in getting rid of these bad invaders. It can be challenging to see these cavities. Hence, they are caught with the use of x-rays.

What Bacteria Causes Dental Caries – The Process

Many microorganisms are involved in the formation of dental caries, the most important including the ones mentioned above. These organisms metabolize sugars from our food and produce Lactic acid as by-products.

When the acidity increases, the pH level reaches a critical level of about 5.2-5.5 for enamel and 6.0-6.5 for dentine. Demineralization of the tooth surface occurs, which eventually results in the formation of caries.

However, if the pH level rises again above this critical pH point, the process is reversed, and remineralization of the tooth surface occurs instead.

The stages of caries development, vector illustration

Top Causes of Bacteria in Dental Caries

Poor dental hygiene – Infrequent and improper flossing and brushing of teeth put individuals at a higher risk of developing caries.

Tooth structure and enamel makeup – This is based purely on genetics; some people are born with deeper tooth crevices and weak enamel.

Sugary foods – This spans beyond a good number of foods. Not only candy causes this, but fruit and juices can be damaging.

Acidic foods and drinks – Adding more acidic substances to the acid produced by the bacteria in your mouth is never a good thing; this should be avoided.

Dry mouth – Saliva contains some biological properties that help limit bacteria growth. A dry mouth can be due to several factors like medications, medical dysfunction, genetics, or congestion.

Types of Dental Caries

1. Primary caries: Primary caries is an initial lesion that produces by direct extension from an external surface.

2. Secondary caries: Secondary caries is an anomaly that occurs on the tooth after the filling method for some time. Secondary caries is also a key factor for the replacement of dental restorations.

3. Other classifications

a. Classification by the rate of attack:

  • Acute caries, Chronic caries, and Arrested caries

b. Classification by the site of the attack:

  • Pits and fissure caries, Smooth surface caries, Root caries (cemental caries), and Recurrent caries
Chewing side teeth of the upper jaw after treatment of caries

What Bacteria Causes Dental Caries – Risk factors

Everyone is at risk of dental caries because we eat daily and sometimes forget to brush/flush; it gradually develops over time; this causes loss of the enamel and dentine layer due to excessive acid production resulting from the metabolism of sugars by bacteria.

Early stages are often void of symptoms, but advanced stages of dental decay may lead to pain, infection, abscess formation, or even sepsis.

Henceforth, everyone with a tooth is at risk for tooth decay; this occurs due to the microorganisms in our mouths that make everyone a potential candidate for cavities and decays. Risk factors that increase the risk for dental caries include:

  • Diet high in refined carbohydrates and sugars
  • Living in environments with limited or no fluoridated water supply. 
  • Poor oral health 
  • Decreased saliva flow
  • Being a child or teenager
  • Being an older adult
  • Socioeconomic status

What Bacteria Causes Dental Caries – FAQ

1. What is the major cause of dental caries?

Dental caries develops when bacteria in the mouth metabolize sugars and carbohydrates to produce acid that negatively alters the hard tissues of the teeth, both enamel, and dentine.

2. What is the difference between dental caries and cavities?

Dental caries also known as tooth decay is damage to the tooth that can happen due to decay-causing bacteria in your mouth; this can lead to the creation of a small hole in the tooth called a cavity. If tooth decay is untreated in time, it can cause infection, pain, and even tooth loss.

An endodontist working with a patient


To sum up, it is noteworthy that although the answer to ‘what bacteria causes dental caries’ has been explicitly explained, they are still easy to build and can transfer from mouth to mouth.

That is why we should avoid sharing toothbrushes among close friends and relatives. Teeth scaling is also another method of deep cleaning the teeth to get rid of these bacteria.

For young children, the most common source of contacting and transferring the bacteria is from their parents; this is evident via sharing each other’s food, an unclean baby’s bottle, or even a loving kiss.

All of this can potentially transfer bacteria from one person to another. While it is most likely inevitable that a child will host these cavity-causing agents, it is medically advisable to limit their exposure as much as possible.

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