Fluoride Recommendations and Preventing Tooth Decay

Fluoride is a naturally occurring substance. Fluoride helps to strengthen the hard outer layer of teeth called enamel. When teeth are stronger they are less likely to get cavities.

Fluoride can be found in many sources, including:

  • Naturally-occurring in well water
  • In certain foods we eat and beverages we drink
  • In most brands of children and adult toothpastes
  • As a varnish, gel, foam, or liquid rinse that a dental professional may apply
  • As a daily or weekly rinse, a lozenge, or a daily supplement found at the drug store
  • Added to some municipal drinking water (water fluoridation)

How Does Fluoride Work?

Fluoride increases the resistance of tooth enamel to acids. Acids are formed by bacteria that are normally present in the mouth and can lead to decay. The presence of low levels of fluoride, up to 1 ppm in drinking water, can reduce cavities as much as 40%. Fluoride helps to reduce the risk of tooth decay in three ways:

  1. It makes the tooth stronger and more resistant to tooth decay.
  2. It can repair tooth surfaces where early tooth decay has occurred.
  3. It inhibits bacteria from producing acids that cause tooth decay.

What is water fluoridation?

Water fluoridation is the process whereby the natural level of fluoride in a water supply is adjusted to a level that will optimize dental benefits.

Fluoride additives meet standards for quality and purity before they are added to water at the recommended levels.

Is drinking water fluoridated in Grey Bruce?

In Grey Bruce, only the city of Owen Sound adds fluoride to the water supplies to bring it up to the recommended levels.

Fluoride occurs naturally and is often found in water sources; levels vary in drinking water throughout Ontario. Naturally occurring fluoride can be found in Grey Bruce, particularly in Western Bruce County


Fluoride in Well Water

Fluoride levels in well water can vary considerably. Well owners may test their well water for fluoride. To determine your well water fluoride levels, have your well water tested.

It is recommended that all residents brush their teeth twice daily with fluoridated toothpaste to prevent cavities based on the guidelines below.


Guidelines - Using Fluoride Products to Prevent Tooth Decay

Fluoride Toothpaste


A rice grain sized portion of toothpaste on a child's toothbrush is shown on the left. A pea-sized portion of toothpaste is shown on the right. Image and text Copyright © 2008 Canadian Dental Association



  • Toothpaste with fluoride should be used twice a day.
  • Children less than three years should have their teeth brushed by an adult, using a rice grain sized portion of fluoridated toothpaste until the child can effectively spit out.
  • Once a child can spit out (usually three years of age), they should be supervised using no more than a pea-sized portion of fluoridated toothpaste.
  • Too much fluoride from any source, including toothpaste, can cause dental fluorosis. Fluorosis is a cosmetic condition that appears as white chalky spots on the tooth surface. That is why it is important to use the appropriate amount of toothpaste for a person's age. Your dentist can provide you with more information on how much toothpaste is right for you.
  • Parents/caregivers with children six years and younger should apply the recommended amount of toothpaste to the toothbrush and supervise to ensure proper brushing.


Fluoride Mouth Rinses

  • Fluoride mouth rinses can prevent cavities for people at high risk of cavities.
  • Not recommended for children under 6 years of age.
  • Talk to your dental professional to determine if they are appropriate for you.


Topical Fluoride/Fluoride Varnish

  • Dental professionals may apply fluoride directly to tooth surfaces in the form of fluoride gels, foams and varnishes to prevent tooth decay for individuals at risk.


Fluoride Supplements

  • Fluoride supplements come in chewable tablets, lozenges or drops and should only be used by people who have a high risk of developing dental decay.
  • Talk to a dental professional before taking any fluoride supplements.


Organizations that support water fluoridation:

A number of reviews on the effectiveness of water fluoridation have been conducted over the last 10 years. Over 90 dental and public health organizations support fluoridation, including:

  • The World Health Organization
  • Health Canada
  • The Canadian and American Dental Associations
  • The Canadian Public Health Association
  • The U.S. Centers for Disease Control and Prevention (CDC)


Information about water fluoridation:


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