The Effect of High Intensity Focused Ultrasound on Enterococcus Faecalis Biofilm

Abstract

Objective: In this study the effect of High Intensity Focused Ultrasound (HIFU) on E.faecalis biofilms was investigated. Methods and Materials: Biofilms were grown on both petri dishes and root dentin for 2 weeks and exposed to HIFU waves generated at frequency 250 kHz and driving voltage 120V. HIFU exposures of 30, 60, and 120 s were compared with control (no HIFU treatment). In addition, effect of HIFU exposures with different irrigants were also compared with conventional irrigation technique on the removal and killing of biofilms on root canals. Results: The removal effect and bacterial viability were studied by scanning electron microscopy, confocal microscopy and colony forming unit respectively. The removal and/or bactericidal effects of HIFU are dependent on the exposure time. Moreover, a significant reduction in biofilm was seen when NaOCl was used together with HIFU. This study highlighted the potential application of HIFU as a novel method for root canal disinfection.