Professional Fluoride Treatment: How It Helps Prevent Cavities

What is professional fluoride treatment?

It is a high-concentration fluoride application that your dentist places directly on your teeth in the office. It is used to prevent cavities in people at risk and, in some cases, to stop early lesions from progressing.

The difference from toothpaste is concentration. Sodium fluoride varnish at 2.26% contains 22,600 parts per million (ppm) of fluoride, and acidulated phosphate fluoride gel at 1.23% contains 12,300 ppm (Fluoride: Topical and Systemic Supplements, ADA). The toothpaste you use at home has far less and is meant for daily use. The two work together.

How fluoride protects your teeth

Cavities do not form overnight. Plaque bacteria produce acids that dissolve minerals from enamel, and saliva puts some of them back. When the loss outpaces the repair, a lesion forms.

Fluoride works mainly at the tooth surface:

• It promotes remineralization. It helps minerals redeposit in enamel that has started to demineralize.
• It makes enamel more resistant to acid. Mineral that forms in the presence of fluoride is harder to dissolve.
• It interferes with bacteria. At high concentrations, it reduces the ability of plaque bacteria to produce acid.

That is why an early lesion, the chalky white spot that appears before there is a hole, can sometimes be stopped or reversed without a filling.

What the evidence shows

The Cochrane review of fluoride varnish in children and adolescents pooled 22 clinical trials. Compared with no varnish or a placebo, varnish was associated with a 43% reduction in decayed, missing and filled surfaces in permanent teeth and a 37% reduction in baby teeth. The authors rated the quality of the evidence as moderate, because many studies had a high risk of bias and their results varied widely (Fluoride varnishes for preventing dental caries in children and adolescents, Cochrane 2013).

The ADA states that varnish must be reapplied at regular intervals, with at least two applications a year for sustained benefit, and that gel is generally applied every 3 to 12 months. The exact frequency depends on your cavity risk. Its clinical guideline recommends these products for people at risk of cavities and, for children under 6, recommends varnish only (Topical fluoride for caries prevention, JADA 2013).

Types of professional fluoride

Fluoride varnish. It is painted onto the teeth with a small brush and forms a sticky coating that keeps fluoride in contact with the enamel for longer. It is the recommended option for young children.

Fluoride gel. It is placed in trays that fit over the teeth for a few minutes.

Silver diamine fluoride. A liquid applied to a cavity to stop it from progressing. The 2018 ADA guideline on nonrestorative treatments lists 38% silver diamine fluoride among the most effective options for arresting or reversing carious lesions (Guideline on nonrestorative treatments for carious lesions, JADA 2018). It has one major drawback: it stains the decayed area black. The ADA also notes that a single application may not be enough for lasting benefit. For those reasons it is usually considered for baby teeth, for areas that are not visible, or when a filling cannot be placed at that time.

The choice depends on age, cavity risk and the condition of the teeth.

Who benefits most?

Anyone at risk of cavities. In practice, that often includes:

• Children, especially if they have already had cavities.
• Adults with receding gums, because exposed roots have no enamel and are more vulnerable to decay.
• People with dry mouth from medications or a medical condition.
• People wearing orthodontic appliances or with many restorations.
• People with sensitivity in exposed areas, since in-office fluoride also helps reduce it.

Frequently asked questions

Is it safe for young children? Yes, when a professional applies the right dose. Citing the CDC, the ADA notes there is no published evidence that professionally applied fluoride varnish is a risk factor for dental fluorosis, even in children under 6.

Does it hurt? No. It needs no anesthesia and takes a few minutes. Afterward you will be told how long to wait before eating or brushing.

If I use fluoride toothpaste, do I still need the professional kind? If your cavity risk is low, fluoride toothpaste and good hygiene may be enough. If it is high, professional fluoride adds to what you do at home; it does not replace it.

Fluoride as part of your prevention

Fluoride works best alongside everyday habits:

• Brush twice a day with fluoride toothpaste.
• Clean between your teeth daily.
• Cut down on how often you have sugary foods and drinks.
• Keep up with checkups as often as your dentist recommends.

Before cosmetic treatment such as veneers or Invisalign aligners, cavity risk is reviewed as well. Veneers are bonded to the tooth and their edges need to stay healthy; with aligners, plaque and sugary drinks can stay in contact with enamel for longer. Keeping cavities under control before and during treatment helps protect the result.

Next steps

You can read more in the sources consulted: Fluoride: Topical and Systemic Supplements, ADA, Fluoride varnishes for preventing dental caries in children and adolescents, Cochrane 2013, Topical fluoride for caries prevention, JADA 2013 and Guideline on nonrestorative treatments for carious lesions, JADA 2018.

If you have a history of cavities, sensitivity or receding gums, or want to review your family's prevention plan, you can schedule an individualized assessment. During the assessment we can evaluate your cavity risk and suggest a prevention plan designed for you.