The effect of EDTA in 3%, 5%, 10% e 17% concentrations in the removal of the smear layer.

The success of microbial disinfection of the endodontic space depends on the endodontic instruments, the ancillary chemicals selected and the technical skills used in the chemical-mechanical preparation. Upon completion of the instrumentation the deposition on the dentine surface of an organic and inorganic material extract of amorphous aspect, with an irregular and granular surface known as residual layer, was observed. Aiming at removal of this layer several chemicals, in different concentrations and applied in pre-established time intervals were used alone, conjugated or mixed. The objective of this study was to analyze, in vitro, through scanning electron microscopy, the effect of EDTA in 3%, 5%, 10% and 17% concentrations on the removal of the residual layer and cleaning of the dentine tubules through applications ranging from 1 to 3 minutes. Eight units from an 80-tooth sample were randomly selected to compose the negative control set (GC1) and other 8 units to compose the positive control set (GC2). The remaining 64 composed the 8 experimental sets (GExp.). Analysis of the photomicrographs at magnitude 2000X revealed that the 10 % and 17 % EDTA solutions were the most effective irrespective of the pre-established application times. It was also observed that the apical third showed a lower degree of cleaning than the cervical and basal thirds.