RESUMEN
INTRODUCTION: The aim of this study was to compare the effect of different application techniques of ozone on the prevalence of postendodontic pain in patients undergoing single-visit root canal treatment. METHODS: hundred eight patients with necrotic pulp in single-rooted teeth and apical periodontitis participated in the trial. A standard single-visit endodontics protocol was followed with 5.25% sodium hypochlorite and rotary nickel-titanium files. After shaping and cleaning, patients were randomly allocated into the following groups: group 1 (n = 21), ozone treatment with no activation (NA); group 2 (n = 22), ozone treatment with manual dynamic activation (MDA); group 3, (n = 21), ozone treatment with passive ultrasonic activation (PUA); group 4 (n = 23), ozone treatment with sonic activation (SA); and group 5 (n = 21), no ozone treatment (the control group). Patient levels of discomfort were recorded at 6 different time intervals using the visual analog scale (VAS). Comparison of the mean difference between the groups and time intervals was performed using 2-way analysis of variance followed by a post hoc Bonferroni test. The level of significance was set at 5%. RESULTS: VAS scores were highest for the control > NA > MDA > SA > PUA groups. A statistically significant reduction in VAS scores was observed in the PUA and SA groups in comparison with the NA, control, and MDA groups. Timewise comparison showed a highly significant decline in VAS scores at all time intervals (P < .001). CONCLUSIONS: Ultrasonic and sonic activation of ozone resulted in less pain in patients undergoing single-visit endodontics compared with no ozone treatment.