Do you ever wonder why people get cavities, even when they brush their teeth twice a day? How do cavities form and how can you prevent them?

Did You Know?
The enamel on your teeth is the hardest substance in your entire body!

Your teeth are multi-layered structures and the outer layers are like a force field protecting the dental nerves located in the pulp – the innermost layer. A cavity, also called tooth decay, begins with the breakdown of the outermost part of your tooth, the enamel. Over time, it develops into a hole. The enamel is the toughest part of your tooth, so once a cavity breaks through this layer, it rapidly moves to the inside of your tooth. Once the hole reaches the dental nerves, it can cause a lot of pain!

Did You Know?
About half of all children ages 12 to 15 have at least one cavity.

So how does a hole form in your tooth? We all have some bacteria in our mouths and these bacteria convert foods, especially sugar and starch, into acids. Together, bacteria, acid, food debris and saliva combine to form a sticky substance, called plaque. Plaque begins to form about 20 minutes after a meal. It sticks to surfaces, especially the indentations on your back molars, the edges of any fillings you might have and just above your gums. The acid in the plaque can slowly dissolve the enamel of your teeth, creating a hole (a cavity). By brushing and flossing your teeth really well, you can remove the plaque and stop it from growing on your teeth. Fluoride is also used against cavities. It can prevent plaque from forming on the outside of your teeth. You can buy toothpaste and mouthwash with fluoride.

Did You Know?
The Hindus of India were the first to use a toothbrush (a twig with frayed fibres) in 4000 B.C.

What can you do to lower your risk of getting a cavity?

Brush regularly with fluoride toothpaste, especially in the grooves on your back molars and around your gum line (gently). Brush up and down in a circular motion. If you can’t brush your teeth, rinse your mouth with water after eating. See your dentist twice a year for regular checkups! Limit your consumption of sweets (like cookies and candy) and sugary drinks (like pop).

Learn More!

What’s a cavity?

Dental Cavities

Fun Dental History Facts (pdf)

Article first published February 13, 2012


Carolina earned a Bachelor's degree in Life Sciences from Queen's University. She then continued her studies into graduate school, where she earned a Master's of Science in Anatomy and Cell Biology. She is currently completing her Doctorate in Biomedical and Molecular Sciences, specializing in reproductive sciences and disorders of pregnancy.

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