Mellberg J R, Nicholson C R, Ripa L W, Barenie J
J Dent Res. 1976 Nov-Dec;55(6):976-9. doi: 10.1177/00220345760550064901.
Deciduous teeth were collected from children who received professional prophylaxis with an acidulated phosphate-fluoride (APF) or placebo paste and were analyzed to determine fluoride uptake. Enamel fluoride level was increased by the APF paste approximately 300 ppm at a depth of 2.5 micrometers during the first month after the prophylaxis was administered, after which it returned to pretreatment levels.
