Asmussen, E.&Dreyer JØrgensen, K. The stability of water in the pores of acid etched human enamel.Acta Odont. Scand. 36, 43–44A mechanism is proposed, explaining the fact that drying by compressed air for 5–10 sec. will remove acid and dissolved enamel from the relatively long and narrow pores of etched enamel surfaces. It is a consequence of the proposed mechanism that water in the liquid state is not stable in the pores, and accordingly, that condensation of water vapour on the etched and dried surfaces is not likely to occur. This was confirmed by studying tag formation in etched enamel surfaces under conditions where water vapour will condense on unetched tooth surfaces.