###### Abstract  
In modern endodontics, removal of accumulated hard tissue debris (AHTD) from root canals is requested. In the last decade, different irrigating solutions and activation methods have been successfully tested. Sonic activation has been shown to be effective in the removal of AHTD. Electric current has been tested before in restorative dentistry, but not in endodontics. An experimental electric current delivering device was compared in the removal of AHTD, using microCT analyses. Fifteen single-rooted teeth were shaped with TruNatomy system endodontic files and divided into three groups: negative control group: specimens underwent no activation; EA group: specimens were activated with EndoActivator (EA); EB group: specimens were activated with ElectroBond (EB). The 2D images, 3D images and morphometric analysis from the microCT showed a statistically significant increased AHTD removal when EB was used. Results of the present preliminary study showed that the irrigant activation with ElectroBond is encouraging when compared to EndoActivator along the entire root canal system. The AHTD was significantly statistically reduced, validating the clinical use of electric fields in endodontics.  
acumulated hard tissue debris (AHTD); ElectroBond; EndoActivator; microCT, endodontic irrigation activation; irrigating solutions; smear layer +
Footnote †: journal: Applied sciences  
instruments [10]. However, irrigation is often ineffective in the removal of AHTD from the anatomical complexities of the root canal system [11; 12]. The reviews of literature show that various chemicals have been used as irrigants [4; 9; 13; 14; 15]. Sodium hypochlorite (NaOCI) and ethylenediaminetetraacetic acid (EDTA) are the recommended irrigating solutions because they are able to dissolve organic/necrotic tissue (NaOCI) and inorganic debris (EDTA), respectively [9]. The development of new mechanical instrumentation and innovative techniques has decreased the overall time of the shaping phase at the expense of the time irrigating solutions may be active in the endodontic system [16; 17]. Unfortunately, using only irrigating solutions cannot ensure necessities [18]. Therefore, to enhance their efficacy, various manual and machine-assisted agitation techniques have been offered, including brushes; hand-activated files or gutta-percha cones; and laser, sonic and ultrasonic systems [19]. Sonic activation and passive ultrasonically activated irrigation are two techniques that claim to improve the irrigant's effectiveness [20; 21; 22; 23]. The EndoActivator (EA) (Dentsply Sirona, Ballaigues, Switzerland) is a sonically driven irrigant activation system designed to produce vigorous intracanal fluid agitation that has been shown to increase the efficacy of irrigation better than traditional needle irrigation [21]. In the last decade, in restorative dentistry, the application of an electric current with an experimental device has been shown to be effective in improving the shear bond strength (SBS) of dental adhesives to dentine [24]. Moreover, it reduces nanoleakage as it enhances resin infiltration into the demineralized collagen matrices of acid-etched dentin [25; 26].  
In endodontics, electric current has never been tested before. The electric current delivering device should create an electric potential difference between the endodontic tooth substrate and the ionic irrigating solution inside the root canal producing a constant electric flow. The removal of AHTD should be improved during root canal treatment, and the activation with electric current has never been tested before with endodontic irrigating solutions; therefore, the aim of the present study was two-fold: to investigate the effectiveness of electricity in the removal of AHTD and to compare electricity to a well-known irrigating activation system, sonic technology.