Effect of root canal irrigants on cervical dentine permeability to hydrogen peroxide

Aim To examine the effects of various root canal irrigants on cervical dentine permeability by monitoring the diffusion of hydrogen peroxide (H₂O₂). Methodology Sixty cervical dentine discs were prepared from human third molar teeth. After removal of enamel and cementum, the outer dentine surface was etched with 17% ethylenediamine tetraacetic acid (EDTA) for 1 min. The dentine discs were randomly assigned to five groups according to the irrigant used: A, saline solution; B, 2.5% sodium hypochlorite solution (NaOCl); C, 5% NaOCl; D, 17% EDTA and 2.5% NaOCl; E, 17% EDTA and 5% NaOCl. After irrigation on the inner dentine surface with the various solutions, the diffusion of 30% H₂O₂ was evaluated through each disc using a plastic‐split chamber. H₂O₂ was applied to the inner‐side chamber, while the outer‐side chamber was filled with de‐ionised water. After 30 min of application of H₂O₂, the solution in the outer‐side chamber was collected to determine the concentration of H₂O₂ using a spectrophotometer. Results The penetration of H₂O₂ through dentine in group E was significantly highest, followed by groups D, C, B and A respectively (one‐way anova , P < 0.05). Conclusions Among the irrigants used, 17% EDTA and 5% NaOCl had the greatest effect in increasing dentinal permeability to H₂O₂.