Dharma Ionite-F APF 1.23% Fluoride Foam, 130 mL · Mint Parfait

• Fluoride Gel — A viscous gel, generally applied in the office for 1 to 4 minutes. Products sold in the United States include acidulated phosphate fluoride gel at 1.23 percent fluoride and sodium fluoride gels and foams at 0.9 percent.
• Fluoride Foam — A foamed form of the same fluoride, named alongside gel at the same concentration.
• Fluoride Varnish — The ADA notes varnish is not currently cleared for marketing by the FDA as an anticaries agent, though it has been widely used for that purpose in Canada and Europe since the 1970s.
• Fluoride Rinse — Swirled and spat out rather than held against the teeth. Higher strength rinses, such as 0.2 percent neutral sodium fluoride once a week, must be prescribed by a dentist or physician.
• Fluoride Trays — The carrier, not the fluoride: it is filled with fluoride and the patient bites down on it.
• Disposable Trays — The single-use kind of tray, thrown away after one patient instead of being cleaned.
• Toothpaste — Brushed on at home: the ADA puts over-the-counter paste at 1,000 to 1,500 ppm against 12,300 ppm for an in-office gel.

Age: the ADA states that fluoride rinse is not recommended under 6 years of age because of the risk of fluorosis if the rinse is swallowed repeatedly, and that only 2.26 percent fluoride varnish was recommended for children younger than 6.

Fluorosis risk: because gel is applied at 3- to 12-month intervals, the ADA says it poses little risk of dental fluorosis even in patients younger than 6. The CDC reports no published evidence that professionally applied fluoride varnish is a risk factor for enamel fluorosis, even among children under 6.

Prophy paste is not a substitute: its 4,000 to 20,000 ppm fluoride might restore the fluoride in the surface enamel that polishing removed, but it is not an adequate substitute for fluoride gel or varnish in people at high risk of decay.

Repeat interval: the ADA states varnishes must be reapplied at regular intervals, with at least two applications a year needed for a sustained benefit.