Use fluoride

Fluoride has been shown effective in the prevention of tooth decay for more than 100 years. Up till now fluoride has been widely used.

Food and drinking water

  • Drinking water

    Domestic water in Hong Kong has been fluoridated since 1961. This has led to a great decline in the incidence of tooth decay. Today in Hong Kong, the fluoride concentration in water is 0.5 ppm (parts per million). By drinking fluoridated water, the intake of fluoride is adequate to prevent tooth decay.

  • Food

    Fluoride is found in tea leaves and certain seafoods.

Oral care products

Fluoride is added in most of our oral care products, such as toothpaste, mouthwash and dental floss. Researches have shown that daily toothbrushing with fluoride toothpaste reduces the incidence of tooth decay by 20%. This has proved that fluoride toothpastes are very effective in preventing tooth decay.

  • List of common oral care products with fluoride and directions of use

    Oral Care Products Concentration of fluoride Directions of use
    Adult Toothpaste 1,000 - 1,450ppm Brush the teeth with a pea-sized blob of toothpaste in the morning and before bed at night every day.
    Children Toothpaste 500 - 1,000ppm
    Mouthwash 230ppm 0.05%NaF Rinse for 1 minute daily.
    900ppm 0.2% NaF Rinse for 1 minute weekly.
    Dental Floss Use once daily.
  • Points to note when using fluoride-containing products


    Generally, a young child should use a pea-sized blob of children toothpaste which contains a lower concentration of fluoride. Ingestion of excessive amount of fluoride will lead to dental fluorosis with white patches found on the newly erupted permanent teeth.


    • For most people, there is no need to use fluoride mouthwash. However, for those who are prone to tooth decay, such as patients under orthodontic treatment or after radiotherapy, etc., they need to use mouthwash according to the instruction of the dentist.
    • Children under 6 years of age should not use fluoride mouthwash to avoid accidental ingestion.

Topical fluoride used by professionals

These topical fluoride agents are in very high concentration. The application of topical fluoride on the tooth surfaces can prevent tooth decay or reduce tooth sensitivity. The dental care personnel usually choose a type of topical fluoride which is appropriate for the patient's oral health condition.

Types of professionally used topical fluoride

Photograph showing several bottles of fluoride gel.
  • Fluoride gel

    This type of topical fluoride contains 12,300ppm of fluoride. Dental care personnel will put the fluoride gel onto a pre-formed dental tray and insert it into the patient's mouth for 4 to 6 minutes to allow the fluoride to penetrate into the teeth.

Photograph showing several tubes of fluoride varnish.
  • Fluoride varnish

    This type of topical fluoride contains 23,000ppm of fluoride. It is often used to treat tooth decay at its initial stage. The varnish is applied directly on the affected tooth surface(s).

Points to note after topical fluoride treatment

To allow topical fluoride to fully function, you should not brush your teeth or chew food for at least 4 hours after topical fluoride has been applied on to your teeth.