Tooth Decay: The 5 Most Important Patient Questions!

Dr. Kyle Hornby

Hi! My name is Kyle Hornby and I'm a Kitchener-Waterloo Dentist. A few times a week, I'll deliver a blog post that gives you the information you need to avoid costly dental work, improve your overall health, and learn how to break down the pros and cons of different dental treatments. In today's blog post, I'd like to explore the most commonly asked questions about tooth decay and cavities.

Before I get to it, I want to address how we talk about cavities. Dentists commonly use the terms tooth decay and dental caries. These are equivalent to what people commonly call "cavities". The term cavity suggests that an actual hole exists in your tooth. Sometimes this can be the case. However, most cavities diagnosed at your Kitchener Dentist's office are actually just soft spots.

Tooth decay refers to a decrease in the mineralization or hardness of your tooth. This is why your Dentist will commonly use a dental instrument under light pressure to test for "sticky" or soft areas on your tooth.

Now that we've gotten some basic info out of the way, let's look at the 5 most commonly asked questions about tooth decay.

Here's my list:

1. Can tooth decay be reversed?

There are a lot of misconceptions about whether or not cavities are reversible. They are, and they aren't. That may sound like a strange answer but the "reversibility" of a given cavity depends on its depth.

Small, early areas of demineralization can be re-mineralized or reversed. The key here is that the demineralization or weak spot exists only in your tooth enamel. Once that demineralized area grows to involve the deeper dentin layer, the lesion is no longer reversible. Now it can only progress and get larger.

So, what's the take home message here?

Small weak spots in enamel can be reversed with good oral hygiene and regular calcium and phosphorus supply from our saliva and dairy sources. Weak spots that have grown through the enamel layer to involve the dentin layer underneath, can't be reversed. These must be removed and the lost tooth structure replaced by a dental filling.

2. Does tooth decay hurt?

Almost never. This one really surprises people. Most people assume that cavities hurt. Before I went to dental school, I assumed that cavities hurt, too. What falls out of this assumption is that no pain = no cavities. Unfortunately, that's not a reliable assumption.

In just under 10 years in practice, I've seen many patients with teeth that essentially rotted to the gum line from decay and the patient reports never having felt pain. Now, when cavities become deep and start to encroach on the nerve in your tooth, there's a greater likelihood that you'll feel it. But, we see lots of patients with deep cavities who don't feel a thing.

So, don't count on pain to let you know when something's wrong in your mouth. The presence of pain does not reliably tell you when something's not right.

3. Is tooth decay contagious?

This is a super-interesting question. To answer it properly, we need to understand a bit of basic info about what causes tooth decay and cavities.

Tooth decay happens when harmful bacteria feed on plaque and sugars that collect on your teeth. These bacteria produce acids as a byproduct when consuming plaque and sugars. The acids then break down, demineralize, and dissolve your tooth enamel and dentin.

So, bacteria are the causative agent when it comes to tooth decay.

Now, everybody has hundreds (if not thousands) of different types of bacteria in their mouths. But, some of us have more of certain types than others. Additionally, an infant's mouth may be free from certain types of harmful bacteria.

When we share food, drinking cups, straws or even kiss, we transfer oral bacteria to others. This can boost the degree to which harmful bacteria types colonize a friend or family member's mouth.

In this regard, it is accurate to say that tooth decay is contagious because we can transmit factors that contribute to the disease from person-to-person.

4. Can a cavity cause infection?

A cavity progresses gradually from the surface of your enamel, into dentin and then, if untreated, into the dental pulp. The dental pulp is what people commonly know as the "nerve" in the centre of each tooth.

The bacteria that cause tooth decay move slowly through the dense, mineralized layers of enamel and dentin. It can take years to reach the nerve space. Unfortunately, the dental pulp or nerve space is full of soft tissue and provides little resistance to bacteria which move through it quickly. These bacterial colonies can easily move toward the root tip and eventually into the jaws causing swelling and infection.

From the jaws, a bacterial abscess can spread into soft tissue spaces around the eyes, cheeks, and throat or gain entry into the bloodstream causing sepsis.

So, what are the options if this happens?

Well, to resolve an active infection you'd be looking at either root canal treatment or tooth extraction. Those are both pretty serious procedures. So, it's always preferable to deal with cavities when they're still small and require only a dental filling.

5. Which foods cause tooth decay?

Tooth decay or "cavities" start because harmful oral bacteria have access to a carbohydrate fuel supply. This can be sugar or anything that can be converted to sugar in the mouth. Sugary and starchy foods are public enemy #1 when it comes to developing cavities.

Some of the most harmful foods are soda pop, sticky candies (think toffee and caramel), and white bread and potato chips. The types of sugars matter to some extent but the volume of available carbohydrate is the most important factor.

After you eat snack foods or drink pop, your teeth will feel "fuzzy" and this is especially true around gum line areas. So, the amount of "fuzziness" you feel with your tongue will give you a good idea about how much carbohydrate load is present.

The key is that you need to brush and floss regularly to remove this harmful carbohydrate. While you don't want to starve, your goal should be to starve the harmful bacteria that exist in your mouth. This is how you prevent tooth decay.

Ultimately, minimizing or eliminating intake of pop and energy drinks, high-starch snacks, and sticky, sugary candies will go along way to avoiding cavities.

By Dr. Kyle Hornby, Kitchener Dentist

Our Dentist Office in Kitchener is conveniently located Downtown. We are a short drive away for families in Waterloo, Breslau & St. Jacobs. Our central location means we truly offer family dentistry near you!

This article is not intended to be a substitute for professional advice, diagnosis, or treatment. Accordingly, always seek the advice of your Dentist or other healthcare providers regarding a dental condition or treatment.

Enjoy a fresh start.
Schedule Your Appointment Today.

Our Kitchener Dentist is currently accepting new patients. If you’re ready for a down-to-earth dental office where you are the priority, give us a call today!
Kitchener Family Dentist
Are you looking for a Dentist in Kitchener who is accepting new patients?

With our convenient location, we truly are a Family Dentist near you! Our Dental Clinic Team proudly provides excellent dental care to families and individuals from Kitchener, Waterloo, Cambridge, Breslau and other nearby communities. Emergency dental care is available upon request!


  • Monday 9:00AM - 7:00PM
  • Tuesday 8:00AM - 7:00PM
  • Wednesday 12:00PM - 7:00PM
  • Thursday 8:00AM - 6:00PM
  • Friday 9:00AM - 6:00PM


Google Map
77 Water Street North, Kitchener, ON N2H 5A6

Kitchener Family Dentistry

Waterloo Family Dentistry

Breslau Family Dentistry

Copyright © 2020 | Powered by Enamel Republic

Designed & Developed by Dental Marketing Guy