Application of the 1-Hydroxyethylidene-1,1-Diphosphonic Acid Irrigant in Root Canal Treatment: An Observational Study

Objective: To investigate the radiographic periapical healing after root canal treatment using a novel 1-Hydroxyethylidene-1,1-Diphosphonic acid (Dual Rinse HEDP) irrigant in necrotic teeth with an apical periodontitis. Material and Methods: In this clinical study, 65 patients with necrotic molars, premolars, and anterior teeth requiring root canal treatment were enrolled. Before the commencement of the study, all study participants signed informed consent forms individually. Teeth were mechanically prepared with E3 Azure rotary files, irrigated with Dual Rinse HEDP irrigant, and then obturated with a single-cone technique and bio-ceramic sealer. After one year, 50 patients (15 dropped out) were evaluated radiographically for periapical healing using the Periapical Index (PAI) scores. Fisher's Exact test and Friedman's test were used. The significance level was set at 5%. Results: After one year, the PAI scores of all patients decreased significantly (p < 0.001). Regarding pain, there was a statistically significant decrease in the prevalence of pain after one year of follow-up amongst the different groups of teeth (anteriors, premolars, molars) (p < 0.001). Conclusion: Dual Rinse HEDP, in conjunction with sodium hypochlorite, can be used as an effective irrigant to promote periapical healing.