Summary:
Purpose: to evaluate the effect of EDTA on smear layer removal and on the structure of dentin, after 1 and 10 min of application.
N= 6 extracted single-rooted teeth
Materials/Methods:
•Teeth were instrumented to #60.
•Apical and coronal thirds of each root were removed, leaving a 5 mm middle third that was then cut longitudinally into two equal segments.
•Using 10 ml of 17% EDTA solution, halves belonging to the same root were irrigated for 1 and 10 min, respectively.
•All specimens were subjected to irrigation with 10 ml of 5% NaOCl. Then all the specimens were prepared for SEM evaluation.
Most highlighted Results:
- 1 min EDTA irrigation is effective in removing the smear layer.
- However a 10-min application of EDTA caused excessive peritubular and inter-tubular dentinal erosion.
Clinical significance:
EDTA followed by NaOCl completely removed the smear layer in 1 min.
Irrigation with EDTA should not be prolonged >1 min during endodontic treatment.

