Smear Layer Removal Efficacy Using EndoActivator and EndoUltra Activation Systems: An Ex Vivo SEM Analysis

This study evaluated intracanal smear layer removal using syringe and needle irrigation (ie, conventional irrigation [CI]) with and without adjunctive activation using EndoActivator® or EndoUltra®.

Thirty-five premolars were divided into three experimental groups (n = 10) and a control (n = 5): (1) CI, (2) CI plus sonic activation (EndoActivator), (3) CI plus ultrasonic activation (EndoUltra), or (4) CI using saline. All teeth were prepared to a size #40 K file. Following irrigation, the teeth were split and imaged using scanning electron microscopy (SEM). SEM images were evaluated by: (1) blinded researchers who provided a smear layer score (1-5), and (2) a custom software algorithm that automatically and independently quantified the number of open tubules.

Use of both the EndoActivator and EndoUltra resulted in significantly cleaner smear layer scores at all canal thirds compared to CI (P < .001). The EndoUltra yielded significantly cleaner scores than the EndoActivator at the apical third (P < .001); however, no significant difference was evident in the middle and coronal thirds. The software analysis yielded the same conclusions as the smear layer scores except statistical significance was seen between the EndoUltra and EndoActivator at all canal thirds (P < .02). Of the adjunctive irrigant activators, the EndoUltra opened 94%, 117%, and 26% more tubules in the apex, middle, and coronal thirds, respectively, than the EndoActivator.

The EndoUltra cleaned canals more effectively than the EndoActivator and CI.