Piezoceramic stack actuator speeds up root canal treatment

In Germany, approximately seven million root canal treatments are performed annually. Despite dental files being made from a superelastic nickel-titanium alloy, there is a high risk of these files breaking under stress, necessitating their frequent removal and thorough cleaning.

The newly developed device overlays the file’s rotation with axial vibration in the ultrasonic frequency range. The aim is to reduce the risk of file breakage and improve the efficiency of root canal treatments.

Advantages of the piezoceramic stack actuator

Dr Holger Neubert, head of the Department of Smart Materials and Systems at Fraunhofer IKTS, said in a press release: “By overlaying the rotation with axial vibration, the file gets clogged less quickly, meaning that it doesn’t need to be cleaned so often. Dentists are then able to concentrate much more on their complex work in the root canal. The risk of the file breaking is also reduced.”

He added: “The core idea of combining the two motions of the dental file came from the specialists at the Department of Dentistry at the Rostock University Medical Center. We used piezoceramic stack actuators as the drive element because they are most able to meet the special requirements for vibration amplitude and frequency, size as well as supply voltage.”

Piezoceramic-based actuators bring numerous benefits. Their compact size and rapid, precise operation make them highly efficient and offer ease of control and minimal heat loss. These actuators are composed of multiple layered segments that collectively enhance displacement, allowing for a design that is sufficiently small to navigate the tightest spaces in a patient’s mouth. Additionally, the research team constructed the stack actuator from lead-free materials, adhering to the future requirements of the European directive on the restriction of hazardous substances in electrical and electronic equipment.

Dentists at Rostock University Medical Center conducted trials of the new technology on artificial teeth and obtained positive results.

Additional medical engineering applications

The newly developed technology holds promise for a range of medical applications beyond dentistry, including applications in diagnostic imaging and cancer treatment. Researchers are exploring its use in low-frequency ultrasonic transducers, which offer high penetration depth for tomography. Advances in piezoceramic transducers have led to their miniaturisation, allowing as many as 2,000 units to be incorporated into a standard-sized tomography system. This facilitates the high-resolution 3D imaging crucial for medical diagnostics.

In addition, high-frequency ultrasound transducers are becoming increasingly valuable in fields like dermatology for their ability to provide precise images at shallow depths. Further potential lies in high-performance ultrasonic transducers designed to target and destroy specific tissue areas with focused sonic waves, a technique particularly relevant in cancer therapy.

“Piezoceramic components can be used in a wide array of applications and, thanks to their compactness and performance, are ideal for medical engineering. We are able to develop custom solutions to suit the needs of individual clients,” emphasised Dr Neubert.

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