Cleanliness and erosion of root canal walls after irrigation with a new HEDP-based solution vs. traditional sodium hypochlorite followed by EDTA. A scanning electron microscope study

Objectives: To compare the cleanliness and erosion of root canal walls after the use of a new HEDP (1-hydroxyethane-1,1-diphosphonic acid) -based irrigant with that achieved by irrigation with sodium hypochlorite followed by EDTA. Materials and methods: Forty recently extracted single-rooted teeth were prepared with ProTaper Next files to size X3, using either HEDP-containing 3% sodium hypochlorite, throughout the procedure (n = 20), or 3% sodium hypochlorite followed by a final rinse with 17% EDTA (n = 20), which were both applied with a syringe and needle. Ten additional teeth were prepared and irrigated with saline and served as negative controls. The teeth were split longitudinally and subjected to SEM evaluation for the presence of a smear layer, debris, and erosion of the root canal wall. The Pearson chi-square test was used to compare the results, and the level of significance was set at p ' 0.05. Results: In both groups, there were more cases with a smear layer in the apical third of the root canal than in the coronal third, but the groups did not differ from each other significantly (p = 0.545). The root canal walls in both groups were almost free of debris, showing no difference between the groups (p = 0.342). Moderate erosion of the root dentine was found in 10–26% of the cases in both groups, but severe erosion was detected in only one case in each of the groups, which did not differ significantly from each other (p = 0.606). Conclusion: Within the limitations of the present study, the HEDP-based irrigation solution did not differ from 3% sodium hypochlorite followed by EDTA in terms of cleanliness or the incidence of erosion of the canal wall. Clinical relevance: When used with syringe and needle irrigation, the new HEDP-based irrigant is convenient and safe but should not be expected to result in cleaner canal walls than 3% sodium hypochlorite followed by 17% EDTA.