The action of different irrigant activation methods on engineered endodontic biofilm: an in vitro study

Endodontic infections are biofilm-mediated, demanding effective biofilm eradication from the root canal. Root canal complexities, coupled with bacterial biofilm resistance, pose challenges to thorough disinfection. Irrigation, particularly with sodium hypochlorite, is crucial in endodontics. Activation techniques, like sonic or ultrasonic oscillations, enhance irrigant penetration and biofilm disruption, improving decontamination and treatment outcomes.The aim of the present study was to evaluate the effectiveness of XP Finisher, EndoUltra, Eddy and Irriflex in the reduction of the multispecies endodontic biofilm formed by Enterococcus faecalis, Pseudomonas aeruginosa, Candida albicans and Proteus mirabilis.

A total of 44 single-rooted mandibular premolars were selected and divided into groups for investigation: Group A: Irriflex, Group B: XP Finisher, Group C: Eddy system, and Group D: EndoUltra system. Multispecies biofilms, comprising Enterococcus faecalis, Proteus mirabilis, Pseudomonas aeruginosa, and Candida albicans, were cultured and inoculated into the pre-treated dentinal canals, which were then incubated for 16 days. Following this, the canals were subjected to the respective irrigation protocols. Bacterial counts were assessed using sterile paper points and culture techniques post-irrigation. Additionally, four non-inoculated root canals were used as negative controls for comparison.

EndoUltra achieved the highest reduction in Total Bacterial Count (TBC) with a median decrease of 75% (interquartile range [IQR]: 70-80%), significantly better than XP Finisher (p = 0.001) and Irriflex (p = 0.001). Eddy led to a reduction in Pseudomonas aeruginosa (PA) with a median decrease of 85% (IQR: 80-90%), significantly outperforming Irriflex (p = 0.001) and XP Finisher (p = 0.001). For Enterococcus faecalis (EF), EndoUltra had a median reduction of 70% (IQR: 65-75%), significantly better than Eddy (p = 0.01) and Irriflex (p = 0.001), while XP Finisher resulted in a reduction of 60% (IQR: 55-65%). EndoUltra showed the highest reduction in Proteus mirabilis (ProM) with 80% (IQR: 75-85%), significantly better than Irriflex (p = 0.001) and XP Finisher (p = 0.001), with Eddy also better than Irriflex (p = 0.009). EndoUltra reduced Candida albicans (CA) by 65% (IQR: 60-70%), significantly outperforming XP Finisher (p = 0.001) and Eddy (p = 0.001).

Within its limitations, this study identified EndoUltra as highly effective in reducing bacterial counts, indicating its potential utility in disinfecting root canals. These findings underscore the significance of such methods in enhancing treatment outcomes and addressing root canal infections.