Influence of the sonicare toothbrush on the structure and thickness of laboratory grown Streptococcus mutans biofilms assessed by digital time-lapse and confocal microscopy

Abstract

Purpose: To evaluate the effect of powered brushing with the Sonicare electronic toothbrush on the structure and thickness reduction of S. mutans biofilms using digital time-lapse microscopy (DTLM) and confocal microscopy (CM) techniques. Materials and Methods: S. mutans biofilms grown on glass microscope slides on BHI and 2% sucrose were exposed to Sonicare for 15 seconds with the bristle tips just contacting the slide, and at distances of 0.5, 1.0, and 1.5 mm above the slide. Results: With direct bristle contact, the reduction in biofilm thickness was greater than 99%. DTLM showed the break up and detachment of biofilm caused by the shear forces generated by the rapid bristle motion in real time. The Sonicare was shown to significantly reduce biofilm thickness even when the bristles were 1 mm above the biofilm. The percent biofilm thickness reduction was inversely proportional to the bristle distance. This study demonstrates the Sonicare toothbrush effectively removed biofilm from hard flat surfaces both by direct bristle contact and by fluid dynamic shear forces alone. Clinical significance: The effectiveness of the Sonicare to remove biofilm, even when the bristles were not in direct contact, suggests that the generated shear forces may help remove dental plaque in hard-to-reach areas such as interproximal spaces and periodontal pockets.