Objective To study the clinical effects of three different root canal preparations on endodontic interappoint-ment pain (EIAP) among the elderly.Methods In this study, 292 teeth with acute or chronic pulpitis or apical periodontitis were collected from 265 individuals. The samples were divided randomly into three groups. Three root canal preparations were utilized for groups M, G, and H. Modified single length technique with Mtwo instrument was utilized in group M. Mo-dified step-back technique with Gates-Glidden bur was employed in group G, and step-back technique with stainless steel H-files was employed in group H. The EIAP rates were observed and compared.Results The rates of EIAP for groups M, G, and H were 5.81%, 6.38%, and 19.64%, respectively. A significant difference was observed between groups M and H (P0.012 5).Conclusion Modified single length technique with Mtwo instrument and modified step-back technique with Gates-Glidden bur can reduce EIAP in the elderly.
