Focused Ultrasound as a Replacement for Endodontic Therapy*

Focused ultrasound has exhibited promising results as a therapeutic modality in its ability to minimize the invasiveness of a number of medical treatments that are physically and mentally traumatic to the patient. We propose the investigation of its use for non-invasive endodontic therapy (a.k.a. a “root canal”), with the ultimate goal of removing microbial infection from the root canal system of a contaminated tooth.
To avoid thermal damage to adjacent healthy tissues, we considered using the mechanical effects created by ultrasound, specifically that of cavitation. To generate proof-of-concept data, we designed, constructed, and tested a series of ultrasound transducers that delivered sufficiently low frequencies operating below 300 kHz and pressures below -30MPa to induce cavitation in degassed water with less than 3ppm. Our initial experiments have shown that sufficient ultrasound energy can be transmitted through intact ex vivo human teeth to elicit nonlinear streaming in the root canal of intact ex vivo human teeth. We have also demonstrated the use of equivalent parameters to kill bacteria. We will further determine and refine the optimal ultrasound parameters for eliciting bactericide in the intact tooth.