What Causes Cavities?

What Causes a Cavity/Dental Caries?

A cavity is defined as a biofilm-mediated, sugar-driven, multifactorial, dynamic disease that results in the phasic demineralization and remineralization of dental hard tissues. Cavities, or dental caries, result from a combination of factors. However, dietary sugars are the most important risk factor for dental caries. Dental caries affect ≤80% of the world’s population with almost a quarter of US adults having untreated caries.

‍

Sugar - The Main Culprit

Sugar directly fuels bacteria in the mouth that produce acids, which weaken the tooth’s enamel, the outermost protective layer.

‍

Bacteria Feed on Sugar

Bacteria are considerably the most dominant form of microorganisms existing in the human oral cavity. Naturally occurring bacteria in the mouth, such as Streptococcus mutans, feed on sugar. When we consume sugary food or drink, these bacteria consume the sugars as their energy source and, as a byproduct, produce acid.

‍

Acid Production

The acids created by bacteria lower the pH level in the mouth. When the pH falls below 5.5, an acidic environment forms that begins to dissolve the minerals in tooth enamel. This process, known as demineralization, occurs as the enamel—the hardest substance in the body, composed of 96% minerals—starts to weaken and erode. Although strong, enamel is not indestructible.

‍

Prolonged Exposure

Sugary foods and drinks often linger on the teeth and in the mouth for extended periods, allowing bacteria more time to produce acids. Sticky foods and sugary beverages are especially harmful because they adhere to the teeth and continue to fuel bacterial growth over time.

‍

Frequent Sugar Intake

Frequent snacking, sipping on sugary drinks, or sucking on candies provides a constant food supply for bacteria, keeping the mouth in a prolonged acidic state. This continuous exposure significantly increases the risk of tooth decay.

‍

Lack of Neutralization

One of saliva’s natural roles is to neutralize acids and replenish enamel minerals, helping to defend against tooth decay. However, excessive sugar consumption can overwhelm this defense, allowing acids to attack and weaken enamel faster than it can be repaired.

‍

Dry Mouth

Saliva not only neutralizes acids but also helps wash away food particles and delivers essential minerals back to enamel. Conditions that reduce saliva flow, such as certain medications, medical conditions, or dehydration, increase the risk of cavities. Limiting carbohydrates and sugary foods and drinks can significantly reduce the risk of cavities. Additionally, regular brushing, flossing, and using fluoride products will help protect enamel from acid attacks.

‍

References

‍

1. Moynihan, Paula. “Sugars and Dental Caries: Evidence for Setting a Recommended Threshold for Intake.” Advances in Nutrition (Bethesda, Md.), U.S. National Library of Medicine, 15 Jan 2016.
2. What Are the Effects of Sugar on Teeth? | Colgate.” What Does Sugar Do To Teeth?, 30 Aug 2024.
3. Syed F., Daboor S. M., Azab A. M., Nori E. E. A Review on Streptococcus Mutans with its Diseases Dental Caries, Dental Plaque and Endocarditis. Indian J Microbiol Res 2015;2(2):76-82.

‍