A device and method for enhanced fluoride uptake by are provided herein. The method includes pre-treating the teeth with a metal salt solution, and then treating the teeth with a fluoride gel and electrical current. A pretreatment tray includes a sponge for absorbing metal salt solution and for prevention of leaking thereof into the mouth. The treatment device includes at least two electrodes, and an applicator for applying an ionizable fluoride substance to the teeth. A current flow is provided, which flow runs through the device and external to the body of the individual.