Removal of plaque and biofilm are keys to the reduction of cariogenic microorganisms and the improvement of oral health. The efficacy of manual brushes is limited to contact with tooth surfaces for bacterial removal. Sonic brushes use both contact and hydrodynamic shear forces to remove plaque. The oscillation of the brush head creates fluid movement causing cell wall disintegration, biofilm disruption, and microbial disadhesion. There is also speculation that sounds generated by the sonic energy also play a part in biofilm change. This study tested the effects of sonic activity and shear force on 4 specific bacteria found within biofilm, L. acidophilis, V. alcalescens, S. mutans, and S. salivarius, which were isolated from human dental plaque and plated on enamel disks coated with artificial saliva. Each group of microorganisms was tested for exposure to acoustic energy at zero, 5, 15, and 30 seconds. Toothbrush bristles were maintained at 7 mm from contact with the plaque to ensure that fluid force alone was responsible for removal of the biofilm. Results indicated that bacterial counts of S. mutans and S. salivarius were significantly reduced at 15 and 30 seconds of exposure. L. acidophilus and V. alcalescens showed no significant reduction regardless of exposure time. S. mutans showed the greatest reduction at the 15-second interval. Acoustic energy has differing effects on the bacteria in biofilm and the ability to disrupt cariogenic microorganisms.
(Source: Dental Abstracts, Volume 51, Issue 6, 2006)
