Fluoride treatments safely provide optimal protection for your teeth, delivering the highest fluoride concentration possible. Your dentist may suggest a fluoride treatment, particularly if you have never received one or if it has been some time since your last treatment. After applying fluoride, either via a treatment foam or a rinse swished in your mouth, you may notice a thin coating of the varnish on the surface of your teeth. Fluoride is a highly effective treatment to protect your teeth against cavities.