Hygiene Atlas

Start here · Liquids · Patient-side products

Fluoride gel or foam (APF)

Also called: APF, acidulated phosphate fluoride, tray fluoride

Fluoride gel or foam placed in trays over the teeth for a few minutes.

Acidulated phosphate fluoride (APF) gel or foam is 1.23% fluoride (12,300 ppm) and acidic (pH about 3.5). It is placed in trays and held on the teeth, usually for 4 minutes. Because it is acidic, it can etch porcelain, composite, glass ionomer and titanium implants.

How to spot it

  • A bottle of flavored gel or foam and disposable foam trays.

What it is used for

  • Seat the patient upright, use a small amount in each tray, and use suction to limit swallowing.
  • Patients avoid eating and drinking for 30 minutes afterward.

Safety and care

  • Do not use APF on patients with porcelain, composite or implant restorations; a neutral sodium fluoride may be chosen instead.
  • Swallowing a lot of fluoride can cause stomach upset; use only the needed amount.

Related

Sources: ADA Oral Health Topics. Fluoride: Topical and Systemic Supplements, Boyd LD, Mallonee LF, Wyche CJ. Wilkins' Clinical Practice of the Dental Hygienist, 14th ed. Jones & Bartlett, 2024