In vitro biofilm removal by an ultrasound power toothbrush

Objective: Electric-powered and high frequency toothbrushes have been used as oral hygiene tools for mechanical plaque removal. This in vitro study compared the ability of a new power toothbrush employing ultrasound to remove dental plaque bacteria as compared to other commercially available power toothbrushes. Methods: Dental plaque was modeled with Streptococcus mutans biofilm formed on hydroxyapatite (HA) discs (5mm diameter) in 1 % sucrose BHI broth. Discs containing biofilm were exposed to: a) oscillating brush (Oral-B® Triumph™; OT), b) sonic brush (Sonicare® Elite®; SE), c) ultrasound power toothbrush (Ultreo™; UL), or d) Ultreo™ with ultrasound disabled (UN). HA discs with biofilm without treatment served as a control. HA discs with adherent S. mutans biofilm were positioned at 3 mm from bristle tips or ultrasound waveguide, exposed to test toothbrushes for 5 sec (in PBS or dentifrice slurry), rinsed with PBS, and the remaining adherent S. mutans removed by sonication (3 sec, 8 watts). Viable bacterial counts were determined. Image analysis procedure was also employed to visually assess biofilm removal from HA discs. Results: The removal of S. mutans by test toothbrushes, as demonstrated by microbiological analysis, were 40.88% for OT, 47.81% for SE, and 76.85% for UL respectively (p<0.001). UL demonstrated the highest biofilm removal among the three test toothbrushes. However, significantly lower removal was seen when the ultrasound was disabled (UN, 20.18%). Similar findings were obtained from the image analysis, with UL showing the highest amount of biofilm removal (OT, 6.49%; SE, 4.42%; UL, 43.87%; and UN, 4.41%; p<0.001). Conclusion: Based on data obtained from this in vitro model study, ultrasound power toothbrush demonstrated superior biofilm removal ability from surfaces without bristle contact (Research supported by Ultreo, Inc., Redmond, WA)