Dentine microhardness changes following conventional and alternate irrigation regimens: An in vitro study

To compare the changes in microhardness of root dentin caused by two novel irrigation regimens with conventional irrigation.

Forty extracted human permanent incisor teeth were selected. Decoronated roots were separated longitudinally to get 80 specimens that were embedded in autopolymerizing acrylic resin and grounded flat with silicon carbide abrasive papers. Of these, 60 root segments without any cracks or defects were selected and divided into four groups according to the irrigation regimen used (n = 15). Group I: 5% sodium hypochlorite (NaOCl) + 17% ethylenediaminetetraacetic acid (EDTA) + 0.2% chlorhexidine digluconate (CHX) (conventional). Group II: 6% Morinda Citrifolia Juice + 17% EDTA (MCJ). Group III: 5% NaOCl + Q Mix 2 in 1 (QMix). Group IV: Distilled water (control). Irrigation regimens were performed for 5 minutes. Dentin microhardness was measured with a Vickers indenter under a 200-g load and a 20-s dwell time at the midroot level of root dentin. The data were analyzed using Kruskal Wallis test and Dunn's multiple comparison tests.

A significant difference was seen in the median values of the four groups. The control group showed the least reduction in microhardness when comparison with the other groups. Except for Group III (Q Mix), the other groups that were tested (MCJ and conventional regimens) showed statistically significant difference from the control group.

Within the limitation of this study, it was concluded that NaOCl + Q Mix were least detrimental to root dentin microhardness when compared with MCJ and conventional irrigation regimens.