Objective : I n vitro analysis of free surface enamel ( g s ) i n dental enamel after treatment with different concentrations of sodium trimetaphosphate (TMP) or calcium glycerophosphate (CaGP), exposed or not to the solution containi ng calcium (Ca) and ph osphate ( PO 4 ), as well as to determine the adsorption of TMP, CaGP, Ca and P O 4 to the dental enamel. Design: Bovine enamel blocks (n = 192; 24 blocks/group) planned were treated (2 mL/ block; 2 minutes) with TMP (0, 1, 3 e 9%), CaGP (0, 0.25, 0.5 e 1 %) ex posed or not to the solution containing CaPO 4 were analyzed in the solutions before and after the treatment will be de- termined for the calculation of the adsorption of these to the enamel . The g s and their components g s LW Lifshitz - van der Waals surface tens ion component , g s AB and Lewis acid - base interaction ( g s + / g s - ) was calculated by measuring the contact angles of three liquids probes (deionized water, diiodomethane and ethylene gly- col). The data were submited to ANOVA followed by Student - Newman Keuls tes t (p<0.05). Results: The adsorption of TMP was dose - dependent (p<0.001) re- duced the g s and g s AB when compared to the group without TMP (p<0.001). The solution containing Ca/PO 4 increased the g s, g s AB and reduced the g s - (p<0.001). There was a correlation b etween adsorption of TMP and Ca (r = 0.916; p<0.001) and P (r = 0.899; p<0.001) to the enamel. The adsorption of CaGP to the enamel was dose - dependent (p<0 . 001) reducing the g s , g s LW and g s - when compared to the group without CaGP (p<0.001). When exposed t he de Ca/PO 4 solution there was an increase of g s LW and g s - , reduction of g s AB (p<0.001), without adsorption of calcium to the enamel. Conclusion : The TMP was adsorbed to the enamel reducing the g s due the g s LW or g s LW , respectively. The TMP generates el ectron - donor inducing adsorption of Ca while CaGP releases Ca to the medium.