RESUMEN
In the present study, 25% EDTA, in gel form, was used to analyse its micromorphological effects on tooth surfaces with the objective to see the effectiveness of EDTA in etching so as to replace phosphoric acid as an etchant. EDTA has neutral pH (6.4 - 7.4) and is known to open & widen the dentinal tubules as well as remove the smear layer. An in vitro study was conducted on orthodontically extracted premolars with 25% EDTA as an etchant which was applied on prepared tooth surfaces for 15 seconds, 1 minute and 3 minutes. The effects of EDTA gel was observed under SEM and results tabulated and evaluated. There was statistically significant differences between the 3 etching time groups and the results indicate that etching with 25% EDTA for 15 seconds is inadequate. The best results were obtained in the 3 minute time etch group. The results so obtained can be attributed to the fact that EDTA acts selectively and/or requires more time for action.