The clinical adhesiveness as expressed by the critical surface tension and roughness of an acid etched tooth surface was studied as a function of time; from time of acid»conditioning«and at selected time intervals up to seven days.The critical surface tensions of the tooth surface were calculated from clinical contact angle measurements as were values for change in roughness. SEM micrographs of the surfaces were obtained for visual comparisons.The results indicate that the surface of the tooth returns to its orginal state of adhesiveness and roughness in a relatively short period of time as a consequence of the adsorption of a biofilm, the acquired pellicle.