How Are Dental Cavities Formed?

I often get asked by my patients in the Boise Idaho area, “What is causing my cavities?!”. Here’s the short answer:

How Are Dental Cavities Formed?

Your teeth are the hardest part of your body. It takes acid to erode this very hard structure. So how is this acid getting on your teeth?


  1. Bacteria in the plaque on your teeth metabolize sugar and simple starches and release acid. This acid, with time, will eat away at your teeth causing cavities.
  2. Prolonged exposure to acidic drinks (think soda and energy drinks) and foods (think limes and lemons, etc.) will also cause damage to your teeth and will leave you more susceptible to getting cavities.
  3. Other health factors such as acid reflux (heartburn), GERD, and bulimia are very acidic and can cause major irreversible damage to your teeth.

However, the biggest culprit of acid and thus cavities is plaque. Let’s understand this process a bit more.

The Role of Plaque:

Plaque is the primary villain in the cavity formation saga. It adheres to the surfaces of our teeth, particularly in hard-to-reach areas like the crevices between teeth and along the gumline. If left undisturbed, plaque can erode tooth enamel, the protective outer layer of our teeth. Plaque has bacteria that consume sugar, and simple carbohydrates and will produce acid as a byproduct that causes demineralization (are teeth have minerals such as calcium, phosphate, and hydroxide that help keep it healthy and strong). This erosion weakens the enamel, making it more susceptible to decay and eventually actual decay and holes in your teeth.

Demineralization (below) – Early stage of the acid attack and cavity. At this stage, the no filling is needed, but it is important to make corrective action and possibly fluoride treatment to prevent further damage.

How Are Dental Cavities Formed?

Cavity (below) – Penetration through the outer layer of the tooth (enamel) and into the inner layer of the tooth (dentin). A cavity has now formed and the damage is irreversible. A filling must be done to prevent further damage.

How Are Dental Cavities Formed?

Several factors can increase the risk of developing cavities:

  • Poor Oral Hygiene: Inadequate brushing and flossing allow plaque to accumulate and thrive, accelerating the decay process.
  • Sugary and Acidic Foods: Consuming sugary snacks and acidic beverages provides fuel for cavity-causing bacteria, exacerbating enamel erosion.
  • Dry Mouth: Saliva plays a crucial role in neutralizing acids and remineralizing enamel. A dry mouth, whether due to medication side effects or certain health conditions, can disrupt this protective mechanism.
  • Tooth Structure and Shape: Some individuals may have deep grooves or irregularities in their teeth that make thorough cleaning challenging, increasing the likelihood of plaque buildup and cavities.
  • Frequency of Snacking: Frequent snacking throughout the day prolongs the exposure of teeth to acids and sugars, heightening the risk of cavities.

Common Questions:

My diet soda has no sugar in it…. so is it bad for my teeth?

Yes!…I would say not as bad as regular soda that has sugar in it, but it’s still acidic and not good for your teeth. However, regular soda has sugar that can fuel the bacteria in plaque so it’s even more harmful

Does Sugar cause cavities?

Kind of. It doesn’t directly, but indirectly. It’s the fuel that feeds the fire.

Are cavities genetic? They seem to run in my family

There is a genetic component to how susceptible people are to cavities. Some people have softer teeth that aren’t as strong as others. It is even more important for these individuals to make sure you don’t miss your dental appointments and get cavities fixed before they get big.

Come in for a visit and read further about how to best prevent cavities!

Dr. Bennion
Horizon Dental
5312 W Overland Rd.
Boise, ID 83705