Ultrasonic Cleaning of Root Canals

A total number of 2000 root canal treatments are performed every day in the Netherlands. In conventional treatments, using syringe irrigation, only a moderate reduction of the amount of micro-organisms can be achieved. The success rate of a root canal treatment is therefore very low: 40% of them will sooner or later be associated with apical periodontitis, an inflammation at the root tip. Passive ultrasonic irrigation through piezoelectric activation of endodontic files could result in a much higher success rate, as this comes close to a bacteria-free situation. Why and how this works remains unclear until today, but microstreaming, cavitation and chemical effects are the most likely working mechanisms.

Figure 1: Schematic drawing of ultrasonic irrigant activation inside the root canal of a tooth with an infected apex.

Figure 2: Air entrainment due to an ultrasonically oscillating file, creating stable and unstable cavitation.

In this project we use high-speed imaging to visualize microstreaming and cavitation inside a (glass model of a) root canal. We also employ Particle Tracking Velocimetry and Laser-Doppler Anemometry, to obtain information on the behavior of the endodontic files and the resulting streaming and cavitation. These experiments will be backed up by theory and numerical simulations of the streaming due to an oscillating file in a confined geometry. We cooperate with the Academic Center for Dentistry in Amsterdam (ACTA) to evaluate our findings in real root canals and with actual biofilms. Our final goal is to obtain a complete understanding of the cleaning mechanisms involved, which may help to improve the efficiency of the devices used in root canal treatments.

Figure 3: Calculated streaming due to a needle with a flat outlet, with the velocity profile plotted on the left side of the needle and the shear stress on the right side of the needle.

See also our project on Megasonic cleaning.

Info: Michel Versluis.

Researchers: Bram VerhaagenMichel Versluis.
Collaborators: Lei-Meng Jiang, Luc van der Sluis (Academic Center for Dentistry Amsterdam (ACTA))
Embedding: JMBC, MIRA Institute for Biomedical Technology and Technical Medicine 
Sponsors: STW


Laser-activated irrigation within root canals: cleaning efficacy and flow visualization
S.D. de Groot, B. Verhaagen, M. Versluis, M.K. Wu, P.R. Wesselink, and L.W.M. van der Sluis
Int. Endod. J. 42, 1077–1083 (2009)BibTeΧ

Max Planck Gesellschaft
4TU Precision Medicine
Centre for Scientific Computing