Safety assessment of an etidronate in a sodium hypochlorite solution: randomized double‐blind trial

Aim To assess whether Dual Rinse HEDP, an etidronate that can be combined with NaOCl to create an endodontic irrigating solution containing both hypochlorite and a chelator in the form of 1‐hydroxyethane 1,1‐diphosphonic acid (HEDP), alters the clinical efficacy of NaOCl or adds any untoward clinical effects. Methodology In this randomized controlled double‐blind single‐centre trial, a pure NaOCl solution was compared to a HEDP‐containing counterpart regarding antimicrobial efficacy, postoperative pain, and the host response by means of changes in MMP‐9 levels in periapical fluid. Sixty patients presenting with asymptomatic apical periodontitis (one tooth each) were randomly divided into two groups (N = 30) based on irrigation regime. Pre‐ and post‐treatment microbial aerobic and anaerobic cultures and MMP‐9/total protein (TP) periapical fluid samples were collected. Postoperative pain levels were assessed 24 h after treatment. Categorical data were compared between groups using the Fisher's exact test, continuous data using the Wilcoxon signed‐rank test, α = 0.05. Results Irrigation with pure NaOCl rendered 40% canals free of culturable microorganisms, compared to 50% with the NaOCl/HEDP mixture (P = 0.60). As assessed by matrix‐assisted laser desorption/ionization‐time‐of‐flight analysis (MALDI‐TOF), no apparent selection of aerobic or anaerobic taxa occurred in either group. One patient in the NaOCl group experienced moderate pain, whilst two patients in the NaOCl/HEDP group experienced mild postoperative pain. MMP‐9/TP levels in periapical fluid declined significantly (P 0.05). Conclusions This trial found no influence of HEDP on clinical NaOCl effects.