Objective: To ensure a successful endodontic treatment, it is important to have a proper disinfection of the root canal. The current study compares the root canal cleanliness and smear layer score between sonic and ultrasonic activation.
Method: Systematic literature review was implemented, using 12 databases. All in vitro studies comparing the efficacy of sonic and ultrasonic activation and reporting at least one outcome of interest were included.
Results: At the apical level, pooling the data in the random-effects model (I2=64%, p = .1) revealed a statistically significant lower smear layer score within the sonic activation group (MD-0.48; 95% CI-0.92, -0.04; p = .03). Furthermore, there was a statistically significant lower push-out bond strength value among the sonic group, in contrast to the ultrasonic group at the middle (MD-0.69; 95% CI-1.13, -0.25; p = .002) and at the apical levels (MD-0.78; 95% CI-1.09, -0.46; p < .0001) of the root canal.
Conclusions: Sonic activation accomplished advancement relative to ultrasonic agitation in removing the smear layer, while ultrasonic activation resulted in significant cohesion between the sealers and the dentine tubules, decreasing the vulnerability of apical leakage and tooth fracture.
Keywords: Disinfection; endodontics; root canal irrigants; sodium hypochlorite; ultrasonics.