A New Weak Chelator in Endodontics: Effects of Different Irrigation Regimens with Etidronate on Root Dentin Microhardness

Abstract

This study investigated the effect of sodium hypochlorite (NaOCl), ethylenediaminetetraacetic (EDTA), etidronic (HEBP), and citric acid (CA) associated in different irrigation regimens on root dentin microhardness. Forty-five root halves of single-rooted teeth were sectioned into thirds that were embedded in acrylic resin, polished, randomly assigned into 3 groups, and treated as follows: G1: saline solution; G2: 5% NaOCl + 18% HEBP, mixed in equal parts; and G3: 2.5% NaOCl. After measurements, the G3 samples were distributed into subgroups G4, G5, and G6, which were submitted to 17% EDTA, 10% CA and 9% HEBP, respectively. Following the new measurements, these groups received a final flush with 2.5% NaOCl, producing G7, G8, and G9. Microhardness was measured with Knoop indenter under a 25 g load for 15 seconds, before and after treatments. The data were statistically analyzed using paired Student's t-test (α<0.05) to compare values before and after treatments and analysis of variance (ANOVA) (α<0.05) to detect any differences among thirds. Except G1, all tested irrigation regimens significantly decreased the microhardness. There were no differences between root thirds before treatments, and all root thirds exhibited equal responses to same treatment. Except saline, all tested irrigation regimens reduced the root dentin microhardness.

Effect of final irrigation protocols on microhardness reduction and erosion of root canal dentin

“…These results are in agreement with those of several previous studies, 8,12,27,28,29 in which these solutions also reduced microhardness. This effect is desirable in the layer next to the canal lumen and it has been associated with increasing calcium loss, resulting in dentin demineralization and softening.…”

“…Knoop hardness was significantly higher for superficial dentin than for deep dentin, 26 presenting sensitivity to surface effects and textures, 13 suggesting that superficial dentin, closer to the pulp, should be analyzed with this method. 27 As in the present study, the Knoop indenter was used in previous investigations to evaluate changes in dentin microhardness. 13,27 Some studies in the literature have evaluated changes in dentin microhardness after canal irrigation with different solutions.…”

“…27 As in the present study, the Knoop indenter was used in previous investigations to evaluate changes in dentin microhardness. 13,27 Some studies in the literature have evaluated changes in dentin microhardness after canal irrigation with different solutions. 8,13,25 However, they have not evaluated initial microhardness, which may render the results imprecise, since the teeth have different initial physical characteristics.…”

1064-nm Nd:YAG and 980-nm Diode Laser EDTA Agitation on the Retention of an Epoxy-Based Sealer to Root Dentin

“…Therefore, sealer retention should be different at cervical to apical third. However, Tartari et al (22) and Macedo et al (14) reported that despite differences in the structure of the roots thirds, the resulting alterations were found to be similar. Our results differ from the previous evaluations and could be explained by the differences within the internal root anatomy, as the apical third present a narrow filled space and could represent a difficult area to the sealer dislodgment.…”

Effect of Nd:YAG (1064-nm) and Diode Laser (980-nm) EDTA Agitation on Root Dentin Ultrastructure Properties

“…Therefore, understanding the characteristics of the irrigated dentin surface is essential in obtaining adhesion of endodontic sealers that have different physicochemical characteristics. 28 In this study, the effects of EDTA laser agitation with different wavelengths on root dentin microhardness and roughness were evaluated and then compared with EDTA alone and EDTA with manual agitation.…”