Current treatment of inflamed root canals is ineffective in 40% of cases, however there is a promising new technique called ultrasonic irrigation. Bram Verhaagen of the University of Twente’s MIRA research institute received his PhD on the latest ideas on ultrasonic root canal cleaning on 28 September. The results may be used to improve the efficacy of current ultrasound devices still further.
Treatment of an inflamed root canal is generally no fun, let alone a second procedure on the same tooth. And yet about 40% of these procedures have to be repeated. Current techniques do not kill all the bacteria in the root canal, so a new inflammation can develop. Fortunately root canal treatment techniques are constantly improving, for example by using ultrasonic irrigation. This involves inserting a thin needle in the root canal and vibrating the irrigation fluid at ultrasonic frequencies. Ultrasonic irrigation cleans the root canal more effectively.
Research has shown that one of the reasons for the failure of traditional root canal treatments is the way the root canal is cleaned, namely by injecting a chlorine solution. Such an injection does not allow the solvent to reach the bacteria hiding in inaccessible places. Cleaning, disinfecting and filling root canals is moreover challenging and time-consuming work.
New cleaning methods
Ultrasonic irrigation makes for better flow and distribution of the chlorine solution and ultimately for a cleaner root canal. Bram Verhaagen investigated precisely how ultrasonic irrigation works, using transparent models of teeth and high-speed photography at one million frames per second. The recordings show that ultrasonic root canal cleaning generates much stronger fluid flows at micro scale, with the result that the chlorine solution is able to disperse better and reach more bacteria. During his measurements Verhaagen also observed tiny bubbles which the ultrasound caused to resonate strongly. The local flow generated by the ultrasound and the bubbles make a major contribution to distributing the chlorine solution.
Valorization in the coming year
The results of the research over the past four years can now be used to improve the efficacy of current ultrasound devices still further, e.g. by making smart use of the tiny bubbles. Eventually a minimally invasive ultrasonic cleaning method that obviates the need for drilling in the root canal would be the ideal treatment. Some ideas on the subject recently won the Young Business Award of the University of Twente’s MESA+ Institute for Nanotechnology.
The research
Bram Verhaagen conducted his research at the Physics of Fluids Group of the University of Twente’s MIRA research institute, under the supervision of Dr Michel Versluis and Prof. Detlef Lohse, both of the University of Twente, and Dr Luc van der Sluis and his colleagues at the Academic Centre for Dentistry Amsterdam (ACTA). The research received financial support from Technology Foundation STW.
