The effect of topical fluoride applications on the surface free energy of human enamel--an in vitro study.

The surface free energy gamma s and its polar and dispersion components gamma Sp and gamma Sd were determined from contact angle measurements on human enamel treated with sodium fluoride, acidulated phosphate fluoride (APF), and aminfluoride solutions. Sodium fluoride solutions only slightly influenced the surface free energy component gamma Sp. The gamma Sp value of the APF-treated human enamel increased from 52 to 66 erg X cm-2. The gamma Sp value after aminfluoride treatment decreased from 52 to 19 erg X cm-2. The gamma Sd values remained about 35 erg X cm-2 for all specimens measured. It is suggested that aminfluoride-treated enamel surfaces may exhibit a reduced tendency for bacterial adhesion.