Related Experiment Video
Updated: Jun 12, 2026
Harvesting and Disaggregation: An Overlooked Step in Biofilm Methods Research
Published on: April 22, 2022
A study of the efficacy of ultrasonic waves in removing biofilms
Takeshi Nishikawa1, Akihiro Yoshida, Amit Khanal
1Division of Maxillofacial Diagnostic and Surgical Science, Department of Oral and Maxillofacial Surgery, Kyushu Dental College, Kitakyushu, Japan.
Objective:
The removal of adherent biofilms was assessed using ultrasonic waves in a non-contact mode.
Materials And Methods:
In in vitro experiments, Streptococcus mutans (S. mutans) biofilms were exposed to ultrasonic waves at various frequencies (280 kHz, 1 MHz, or 2 MHz), duty ratios (0-90%), and exposure times (1-3 minutes), and the optimal conditions for biofilm removal were identified. Furthermore, the effect of adding a contrast medium, such as micro bubbles (Sonazoid), was examined. The spatial distribution and architecture of S. mutans biofilms before and after ultrasonic wave exposure were examined via scanning electron microscopy. The biofilm removal effect was also examined in in vivo experiments, using a custom-made oral cleaning device.
Results:
When a 280 kHz probe was used, the biofilm-removing effect increased significantly compared to 1 and 2 MHz probes; more than 80% of the adherent biofilm was removed with a duty cycle of 50-90% and a 3 minutes exposure time. The maximum biofilm-removing effect was observed with a duty cycle of 80%. Furthermore, the addition of micro bubbles enhanced this biofilm-removing effect. In in vivo experiments, moderate biofilm removal was observed when a 280 kHz probe was used for 5 minutes.
Conclusions:
This study demonstrated that ultrasonic wave exposure in a non-contact mode effectively removed adherent biofilms composed of S. mutans in vitro.
