The aim of the present study was to in- vivo evaluate the antimicrobial efficacy of commercially available ozonated olive oil with and without ultrasonic activation as root canal irrigant in primary endodontic infections and compare with conventional irrigant i.e. 2.5% Sodium hypochlorite.

In the present study, fifty six patients with single rooted teeth were selected. After local anaesthetic administration and rubber dam placement, access cavity was made. Working length was determined using an apex locator and confirmed radiographically. Pretreatment sample (S1) was obtained with a paper point by injecting normal saline (5 ml) into the root canal and transporting it into the peptone water. Biomechanical preparation was done up to the working length with master apical file size #40 and step back up to size #60.  The patients were randomly divided into four groups (n=14) - Group 1: 2.5% Sodium hypochlorite, Group 2: 2.5% Sodium hypochlorite with ultrasonic activation, Group 3 : Ozonated olive oil and Group 4: Ozonated olive oil with ultrasonic activation. Irrigation was done with the respective irrigants during the biomechanical preparation and in Group 2 and Group 4 irrigant was passively activated by ultrasonics. Post instrumentation and irrigation sample (S2) was collected in the same manner as S1. Microbiological samples (S1, S2) were preincubated for 30 minutes and shaken vigorously in a vortex mixture for 60 seconds and then it was plated on Brain heart infusion agar and colonies were counted after 24 hours of incubation using classic bacterial counting method.

The results of this study demonstrated that in intragroup comparison, statistically significant reduction was found from S1 to S2 in all the four experimental groups. In intergroup comparison the mean reduction of bacterial counts of Group 1 (Sodium Hypochlorite) and Group 3 (Ozonated olive oil) were found to be lower than that of Group 2 (Sodium Hypochlorite with ultrasonic activation) and Group 4 (Ozonated olive oil with ultrasonic activation). However, the difference was not statistically significant between Group 1 (Sodium Hypochlorite) and Group 3 (Ozonated olive oil) but the difference was statistically significant between Group 2 (Sodium Hypochlorite with ultrasonic activation) and Group 4 (Ozonated olive oil with ultrasonic activation) with highest mean percentage bacterial reduction seen in Group 2 (Sodium Hypochlorite with ultrasonic activation).