This study examined the effects of a microbubble emulsion (ME) combined with sonic or ultrasonic agitation, on irrigation dynamics and reduction of biofilm bacteria. High-speed imaging was used to characterize the bubble dynamics generated in ME by sonic or ultrasonic agitation within polymer teeth. 5.25% NaOCl or ME was sonically or ultrasonically agitated in canals of extracted teeth with 7-day-old Enterococcus faecalis biofilms. Dentinal shavings were sampled and colony-forming units (CFU) enumerated. Mean log CFU/ml values were analyzed with ANOVA and post-hoc tests. Strongly oscillating and vaporizing bubbles were generated within ME during ultrasonic, but not sonic agitation. Post-treatment biofilm CFU were significantly lower in the ultrasonic agitation (P=0.000) of ME group than in the ultrasonic (P=0.009) and sonic agitation (P=0.006) of NaOCl groups. The synergistic effect of ME combined with ultrasonic agitation enhanced bubble dynamics and reduced E. faecalis biofilm bacteria beyond the level achieved by agitation of NaOCl.

This study examined the effects of a microbubble emulsion (ME) combined with sonic or ultrasonic agitation, on irrigation dynamics and reduction of biofilm bacteria. High-speed imaging was used to characterize the bubble dynamics generated in ME by sonic or ultrasonic agitation within polymer teeth. 5.25% NaOCl or ME was sonically or ultrasonically agitated in canals of extracted teeth with 7-day-old Enterococcus faecalis biofilms. Dentinal shavings were sampled and colony-forming units (CFU) enumerated. Mean log CFU/ml values were analyzed with ANOVA and post-hoc tests. Strongly oscillating and vaporizing bubbles were generated within ME during ultrasonic, but not sonic agitation. Post-treatment biofilm CFU were significantly lower in the ultrasonic agitation (P=0.000) of ME group than in the ultrasonic (P=0.009) and sonic agitation (P=0.006) of NaOCl groups. The synergistic effect of ME combined with ultrasonic agitation enhanced bubble dynamics and reduced E. faecalis biofilm bacteria beyond the level achieved by agitation of NaOCl.