How to Prevent Cavities: 8 Habits That Protect Your Teeth

Written and medically reviewed byDr. Naina BaidyaGeneral Dentist · Updated October 1, 2026

Can You Really Prevent Cavities?

Yes. A cavity doesn’t appear overnight. Decay is a slow tug-of-war between acid and repair, and early on, you can tip it back in your teeth’s favour. The National Institute of Dental and Craniofacial Research on the tooth decay process explains that “Enamel can repair itself by using minerals from saliva, and fluoride from toothpaste or other sources.”

At the white-spot stage, before a hole forms, “Tooth decay can be stopped or reversed at this point.” Once a real hole forms, the enamel can’t grow back and you’ll need a filling. Our guide to a cavity in a tooth covers the signs, stages and treatment. This article is about keeping it from getting that far.

1. Brush Twice a Day With Fluoride Toothpaste

Brushing removes plaque, the sticky film of bacteria that turns sugar into acid. The Ontario Dental Association says to “Brush your teeth at least twice a day”, and the American Dental Association adds to brush with fluoride toothpaste each time.

Two small details make a difference:

Timing

The ODA suggests you “Wait about 30 minutes after eating before you brush so you don’t damage the enamel on your teeth.”

Pressure

Brushing harder doesn’t clean better. The ODA notes that brushing too hard can wear away enamel. A soft brush and gentle circles do the job.

2. Clean Between Your Teeth Every Day

Many cavities start where your toothbrush can’t reach. The ODA puts it plainly: “Brushing alone only cleans two-thirds of the tooth’s surface.” Floss, or use small interdental brushes, once a day to clear plaque and food from between your teeth.

If flossing is hard because of tight teeth, braces or bridges, ask us at your next visit. There’s usually a tool that makes it easier, and we can show you how to use it.

3. Watch How Often You Snack, Not Just What

It isn’t only how much sugar you eat. It’s how often. The National Institute of Dental and Craniofacial Research on the tooth decay process warns that when we eat often, especially sugary and starchy foods, “the repeated acid attacks will win the tug-of-war”. Each snack or sweet drink gives bacteria another round of acid.

• Keep sweets to mealtimes instead of sipping or nibbling all day.
• The ODA suggests “tooth-friendly snacks like veggies, nuts or cheese.”
• After something sugary, the ODA recommends “swishing with water to rinse out your mouth or chew sugar-free gum.”
• Starches count too. The NIDCR lists milk, bread and juice alongside cookies, candy and soda.

4. Get Enough Fluoride, Including From Mississauga Tap Water

Fluoride is the main reason early decay can heal. The Canadian Dental Association fluoride FAQs explain that “Fluoride strengthens tooth enamel, making it more resistant to decay. It can also reverse early signs of tooth decay.”

Here’s a local advantage: Mississauga’s tap water is fluoridated. Peel Region confirms that “Water fluoridation takes place for the South Peel drinking water supply”, which includes Mississauga, adjusted to “0.5 mg/L to 0.8 mg/L” (Peel Region on fluoride in tap water). If you drink tap water, you’re getting a small, steady dose every day.

If you mostly drink bottled water, be aware that the NIDCR says “Most bottled water does not contain enough fluoride to prevent tooth decay.” For people at higher risk of cavities, we may suggest a fluoride varnish at your checkup or a fluoride rinse at home.

5. Ask About Dental Sealants for Back Teeth

The chewing surfaces of back teeth have deep grooves where food and bacteria get trapped, and a toothbrush bristle often can’t reach the bottom. The American Dental Association (MouthHealthy) on preventing cavities notes that “Sealants can be placed on back teeth to better protect them from bacteria causing cavities in the grooves.”

A sealant is a thin coating painted onto the grooves. It’s quick, there’s no drilling, and it’s most often placed on children’s permanent molars soon after they come in. Our kids dentist page explains what a children’s visit at River Run includes.

6. Don’t Ignore a Dry Mouth

Saliva is your mouth’s natural defence: it rinses away food and carries the minerals that repair enamel. The ODA warns that “Dry mouth can speed up the cavity-making process by letting damaging sugars and acids from food and drinks linger in the mouth.”

Many common medications cause a dry mouth. The ADA lists them among the things that raise your cavity risk, along with snacking between meals and a personal or family history of cavities. Sip plain water through the day, and tell us about any medications you take, so we can look out for early decay.

7. Start Good Habits Early for Children

Baby teeth can get cavities too, and habits set early tend to last. The Canadian Dental Association on cleaning children’s teeth recommends cleaning your baby’s mouth even before the first tooth comes in, and says “Children under 3 years of age should have their teeth brushed by an adult.”

How Much Toothpaste for Each Age

The CDA’s guidance depends on your child’s age:

Birth to 3

Ask a health professional whether your child is at risk of decay. If they are, use “a portion the size of a grain of rice” of fluoride toothpaste. If not, use a toothbrush moistened with water.

Ages 3 to 6

Use “a pea-sized amount of fluoridated toothpaste”, with an adult watching so your child spits it out.

When Kids Can Brush on Their Own

The CDA says that when a child “can write (not print) his or her name”, they’re ready to do a good job brushing. Keep checking their teeth afterwards for a while.

8. Keep Up Regular Checkups and Cleanings

Early decay usually doesn’t hurt, so you won’t notice it yourself. Checkups find white spots and tiny cavities while they can still be stopped, and a professional cleaning removes hardened tartar that brushing can’t. The ODA notes that “Regular dental check-ups can catch cavities when they’re small and easier to treat.”

How often you need a visit depends on you. The Canadian Dental Association dental care FAQs say your dentist may suggest coming “more or less often depending on how well you care for your teeth and gums” and how fast tartar builds up. We’ll suggest a schedule that fits your own risk, not a one-size-fits-all rule.

How to Prevent Cavities: A Quick Checklist

• Brush twice a day with fluoride toothpaste, gently, about 30 minutes after eating
• Clean between your teeth once a day
• Keep sugary and starchy snacks to mealtimes
• Drink fluoridated tap water
• Ask about sealants for back teeth, especially for kids
• Sip water if your mouth is often dry, and tell us about your medications
• Brush your child’s teeth for them until they can do a good job alone
• Book regular checkups and cleanings

How To Prevent Cavities: Frequently Asked Questions

Related Articles

• Cavity in a Tooth: Early Signs, Stages and Treatment
• Gum Disease: Early Signs, Stages and Treatment

Sources

• National Institute of Dental and Craniofacial Research on the tooth decay process
• American Dental Association (MouthHealthy) on preventing cavities
• Canadian Dental Association fluoride FAQs
• Canadian Dental Association on cleaning children’s teeth
• Canadian Dental Association dental care FAQs
• Peel Region on fluoride in tap water