Analysis of dentinal erosion and removing smear layer of different irrigation protocols: an in vitro study

Aim: A material with an acidic pH and desiccating action (HybenX) has been generated to destroy the dental biofilm. This study aims to investigate the effect of HybenX used as an irrigating solution, estimating its efficacy in the elimination of the smear layer and rating how it may influence dentinal erosion.

Methodology: One hundred extracted, single-rooted, human teeth were used. Five groups were made in a random way (n=20), considering the type of irrigant used at the end of the instrumentation with ProTaper Gold sequence SX – F4: Group A (NaOCl), Group B (NaOCl – EDTA 17%), Group C (NaOCl - EDTA 17% - NaOCl), Group D (NaOCl - HybenX), Group E (NaOCl - HybenX - NaOCl). The amount of the smear layer and the erosion were evaluated according to the Torabinejad method using a scanning electron microscope. A Kruskal-Wallis test was performed at each portion (i.e. apical, middle, coronal) and overall for both smear layer removal and erosion variables. A multiple comparison analysis was implemented as well within each portion and overall for both variables.

Results: The difference in debris removal at all three levels of the canals was statistically significant, comparing the five treatment groups (p<.0001). The statistic test showed a statistically significant greater erosion overall between group A and the other four groups (p<.0001).

Conclusions: Under the conditions of the present study, the use of a combination of NaOCl and HybenX, efficiently removes smear layer and produces a lower degree of erosion if compared with 17% EDTA.