What Is Tooth Decay?
- Early decay causes no pain, so regular exams matter.
- A white spot can harden again with fluoride. A hole cannot grow back.
- Facial swelling with a fever needs a hospital emergency department or 911.
Many cavities are hard to see in a mirror, so the dentist can show you the tooth on a screen with an intraoral camera.
No single habit prevents decay. Cutting sugar helps and so do fluoride, brushing, flossing and regular checkups.
At What Age Can Cavities Start?
Cavities can start as soon as a baby's first tooth comes in and can form at any age after that. The Canadian Dental Association advises a child's first dental visit within 6 months of the first tooth or by age one.
What Are the Stages of Tooth Decay?
Tooth decay moves through five stages, from a white spot to an abscess.
| Stage | What you may see or feel | What the dentist may suggest |
|---|---|---|
| 1. White spot | Chalky white spot, no pain | Fluoride and a recheck |
| 2. Enamel decay | Light brown spot, small hole | A filling |
| 3. Dentin decay | Darker spot, sensitivity | A filling, onlay or crown |
| 4. Pulp damage | Toothache, red or swollen gum | Root canal therapy |
| 5. Abscess | Face or jaw pain and swelling | Urgent care, root canal therapy or extraction |
What Does a Stage 1 or Stage 2 Cavity Look Like?
A stage 1 cavity is a small chalky white spot on the enamel. In stage 2 the spot turns light brown and a small hole appears. A dark spot on just one tooth points more to a cavity than to a stain.
Can Early Tooth Decay Be Reversed?
Yes. Fluoride can reverse early tooth decay while it is a white spot with no hole, because it helps the enamel take back lost minerals. A dentist may apply fluoride varnish and keep watch on the spot. Once a hole forms the cavity does not heal.
What Are the Signs of a Cavity?
The signs of a cavity are toothache, pain when you bite and sensitivity to sweet, hot or cold. You may also see a hole or a white, brown or black spot on one tooth. Early decay causes no pain, but a white spot can show.
How Does a Dentist Check for Early Decay?
A dentist checks for early decay by looking at each tooth and probing for soft spots. Digital X-rays show decay between teeth and the dentist takes them only when your history and exam show a need. No check can rule decay out. The early cavity detection page covers each method.
How Does Keeping Your Mouth Healthy Stop Decay?
Keeping your mouth healthy lets saliva wash food away and carry minerals back into the enamel. Decay starts when acid attacks come faster than saliva can repair them.
What Causes Tooth Decay?
Tooth decay is caused by plaque bacteria that turn sugar and starch into acid. The acid pulls minerals out of the enamel. Decay then spreads faster in the softer dentin underneath. Acidic foods and drinks such as lemons, tomatoes and soft drinks also wear enamel away.
Who Is at Higher Risk of Cavities?
These raise your risk:
- Snacking on sweets or sipping sugary drinks through the day
- Deep grooves in back teeth
- A dry mouth from some medicines or medical conditions
- Worn fillings or gums that have pulled back from the roots
- Heartburn or an eating disorder
How Is Tooth Decay Treated?
Tooth decay is treated according to its stage, and the dentist recommends what comes next.
Fluoride for Early Decay
Fluoride treats decay at the white-spot stage and the clinic's fluoride treatments page explains how. Silver diamine fluoride is a liquid some dentists paint on a cavity to stop or slow it. It leaves a permanent black stain and can irritate the gums, so ask the team whether it suits you.
Fillings for Most Cavities
A filling treats most cavities. The dentist numbs the tooth, removes the decay and seals the space with tooth-coloured composite. Sensitivity afterwards usually settles within a week or two. Call the clinic if it lasts longer.
The dental fillings page covers materials, steps and cost.
Onlays and Crowns for Large Cavities
An onlay is made in a dental lab and bonded onto a tooth too damaged for a filling but not enough for a crown. This is general information, so ask the team whether an onlay suits you. A crown covers the whole visible tooth when too little strong tooth is left. Shaping the tooth to fit a crown cannot be undone.
What Will a Dentist Do for Severe Tooth Decay?
For severe tooth decay a dentist first tries root canal therapy, which aims to save a tooth once decay reaches the pulp and nerve. A root canal can fail when the damage is severe. The tooth then needs retreatment or an extraction.
An extraction removes a tooth that is too decayed to repair. Its main risks are bleeding, infection and dry socket, a painful loss of the blood clot. A gap lets nearby teeth shift. Ask about a bridge, implant or denture to fill it.
Does Treating a Cavity Hurt?
Treating a cavity should not hurt during the procedure. Freezing numbs the tooth first, so you should feel pressure but not pain. Speak up if something hurts and the dentist can add more numbing.
Soreness is common once the numbness fades. Watch a child until then so they do not bite their lip or tongue.
If you feel nervous, ask the team if nitrous oxide suits you. It can cause drowsiness, nausea and slower breathing, so the team reviews your health first. It fades sooner than other sedation. The team tells you when you can drive.
When Is Tooth Pain an Emergency?
Tooth pain is urgent when it comes with facial swelling or a fever. Call a dentist today if you have one of these.
If you have both, use the 911 line below. My City Dental offers emergency same-day care when available. The emergency dentist page explains urgent visits.
Call 911 or go to the nearest hospital emergency department if you have trouble breathing or swallowing, swelling that spreads toward your eye or neck, fever with facial swelling, or bleeding that will not stop.
How Can You Prevent Tooth Decay?
You prevent tooth decay with fluoride, clean teeth and fewer sugar attacks. The Canadian Dental Association advises brushing at least twice a day with fluoride toothpaste for two to three minutes. Floss daily and replace your soft-bristled brush every three months.
Spit out the toothpaste and skip the rinse so fluoride stays on your teeth. Keep sweet foods and drinks to mealtimes.
An adult brushes a young child's teeth. From age 3 to 6 use a pea-sized amount of fluoride toothpaste. Under age 3 ask the dentist first. If fluoride toothpaste suits your child, use a smear the size of a grain of rice.
Keep getting cavities? Ask the team to check your brushing and flossing at your next visit. Sealants on the deep grooves of a child's back teeth help keep decay out.
Does Insurance or the CDCP Cover Tooth Decay Treatment?
Private plans cover part of decay treatment under their own limits. My City Dental offers direct insurance billing. Your insurer's predetermination is an estimate, not a promise of payment.
My City Dental accepts the Canadian Dental Care Plan (CDCP), and your coverage depends on the service and your eligibility. The CDCP Dental Benefits Guide covers fillings once per tooth surface in any 24 months, needs preauthorization for crowns and some other services, and does not cover bridges or implants.
Frequently Asked Questions About Tooth Decay
Can I wait 6 months to fill a cavity?
No. A cavity with a hole never heals and six months gives the decay time to grow deeper. A cavity that needs a small filling today can need root canal therapy and a crown later. Pain is a poor guide, so book an exam even if the tooth feels fine.
How much does it cost to fix tooth decay?
The cost to fix tooth decay rises with each stage, from fluoride for a white spot to a root canal and crown or an extraction and a replacement tooth. The clinic's fillings, root canal, crown and extraction pages describe each cost. Your own cost comes in a written estimate after an exam.
What should I do with a cavity while waiting for a dentist?
Keep the tooth clean and starve the decay of sugar. Brush gently twice a day with fluoride toothpaste, floss and chew on the other side. Do not push anything into the hole. Call the clinic sooner if the pain grows or swelling starts.