The Science Behind Cavities: What They Are And How to Treat Them

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We all know that a cavity is a bad spot in your tooth that you have to get filled, but they’re also a little more than that. A cavity isn’t just a sore spot – its an actual hole in your tooth that, if left untreated, can expand all the way down to the roots of your teeth and the nerves that are housed there.

What Is a Cavity?

Tooth Anatomy

Before we can get any farther into the science of cavities, we need to go over some basic tooth anatomy. Teeth are composed of three layers: the enamel (the hard part on the outside of the tooth), the dentin (a softer layer under the enamel), and the pulp (houses nerves and blood). The part of the tooth that sits above the gums is called the crown, and the part below the gums is the root.

Cavities typically form in the enamel layer and can progress into the dentin and eventually reach the pulp if left untreated. The cavity also does not form like a tunnel into the tooth – it usually expands and eats away large areas of the tissue.

Signs and Symptoms

Not all cavities are easy to see or detect, but these are the signs and symptoms to keep an eye out for:

  • Increased tooth sensitivity to pressure and temperature
  • Pain when eating, drinking, or constantly
  • Craters in the tooth
  • Bad breath
  • Black or grey discoloration
  • Pus

If you have these symptoms, you should see a dentist as soon as possible. If caught early, most cavities can be fixed easily and with little discomfort; if left to rot, they can cause serious health issues and require surgery to fix.

What Causes Cavities?

Everyone knows that poor oral hygiene and a diet that is high in sugars can cause cavities, but how does this actually happen? Well, cavities occur when a chemical process called demineralization weakens the tooth enamel. As the name suggests, this is when the enamel loses its minerals into the environment, thus causing it to weaken.

Demineralization is caused when the tooth is exposed to an acid environment – no, this doesn’t mean you can’t enjoy your favourite citrus fruits – “acid” here refers to a pH of 5.5 or lower. And where to these acids come from? You’d be surprised. They don’t come from your food directly, but rather the bacteria that live in your mouth.

Bacterial Build Up

The idea that there are cavity causing bacteria in your mouth is….less than appealing. But there are actually millions of resident bacteria that live naturally in your body. This is bacteria that are supposed to be there because they keep you healthy. The same thing goes for your mouth.

The catch is, that the bacteria in your mouth that are helpful in small numbers can also cause damage if the populations grows too large. They live off of the sugars from the foods you eat, and they secrete acids as they grow – the acids that cause demineralization. That is why eating a lot of sugary goods can contribute to the formation of cavities.

Brushing and flossing regularly both removes lingering sugars and helps keep bacterial populations in check.

Where Does Plaque Come In?

No matter how meticulous you are in your oral hygiene habits, you still need to visit a dentist regularly to have them remove stuck on plaque in hard to reach places.


Well, plaque is actually an accumulation of bacteria, sugars, and the damaging acids. It contains everything the bacteria need to flourish – and keeps them right up against the surface of your teeth.

You remove some of this plaque when you brush, floss, and rinse, but you can’t remove it all. The plaque that you can’t reach will harden over time, which makes it better at protecting the bacteria and more difficult to remove. Most dentists recommend coming in to have this cleaned every six months, or at least once a year.

Science Meets Cavity Prevention

We’ve learned about how cavities form and what causes them, so now its time to talk about how to prevent them from happening in the first place. You have probably heard you dentist tell you the importance of regular oral hygiene, but here is what it does and why it is important:

-Brushing: you should brush your teeth twice a day at a minimum, but you can certainly do it more than that. If cavities are a big worry for you – or if you currently have some – you might want to consider brushing after each meal.

Also don’t just brush your teeth. You should also brush your tongue, gums, and cheeks. There are plenty of bacteria lurking in those places as well, but have care when brushing your gums – you don’t want to cause bleeding. 

-Flossing: Dentists often harp on flossing, but few of us actually do it as regularly as we should, to our detriment. Tiny food particles can get stuck between your teeth while you eat, allowing bacteria to build up and form hard plaque.

Flossing removes food and plaque, which can cut down on cavity formation in the hard to reach places in between your teeth.

-Rinsing: The last key component of proper oral hygiene is rinsing with a fluoride mouthwash. You’ll want to swirl a mouthful around for at least a minute, which will knock out any acids and bacteria that are left after your brushing and flossing.

It is important that you don’t use just any old mouthwash. If it doesn’t have fluoride, you don’t want to use it. Fluoride is one of the most effective ways to protect your teeth from demineralization and decay. It kills bacteria, prevents cavities and oral diseases, and it also helps freshen your breath. Contact our NW Calgary dental clinic today.

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