Researchers at the University of Basel have developed a small dental robot that could automatically prepare teeth for crowns in the future. This would reduce the number of appointments required per dental treatment.

The check-up at the dentist ends with bad news: tooth decay has eaten a large hole in the tooth, requiring a crown. Several follow-up appointments are necessary for the treatment. At the first appointment, the dentist removes the decay, fills the hole, and prepares the tooth for the crown. She then takes an impression and fits a temporary crown. The permanent crown is then fabricated based on this impression, and the dentist can only fit it at a subsequent appointment.

This could be significantly faster in the future: with a small dental robot developed by researchers at the Department of Biomedical Engineering at the University of Basel. The idea for it came from researchers at the University of Zurich, who were also involved in the development.

The prototype is about the size of a wine cork; it measures only 43 by 26 by 28 millimeters. Motors and control units are located externally and are connected to the robot via flexible drive shafts, cables, and tubes. “The size is designed so that it fits comfortably in the open mouth,” explains Dr. Yukiko Tomooka, first author of the publication in “IEEE Transactions on Medical Robotics and Bionics , “ in which the research team presents the robot.

Fewer appointments at the dentist

The prototype, called “MIR” (for “Miniature Intraoral Robot”), is designed to prepare teeth precisely according to a digital plan. The vision: After a scan at the first appointment, dentists could plan exactly how the robot should remove the tooth material and order the crown directly – not after a second appointment. 

The scan is used not only for planning the crown, but also for a custom-made dental splint on which the mini dental robot is attached. “Even if the patient turns their head, the ‘MIR’ moves with them,” says Tomooka. 

The dental robot works with remarkable precision.

The researchers tested their dental robot on tooth models made of resin and a ceramic with a hardness similar to tooth enamel. The robot performs the preparation in two steps: First, it reduces the tooth surface with a wide drill, thus removing material from the top. In the second step, a longer, thinner drill works on the sides of the tooth. 

What’s remarkable is how precisely the dental robot already works, even though it currently lacks sensors to directly measure or correct its position. In tests, the positional error was less than 0.2 millimeters and should decrease significantly with the addition of sensors and position correction. 

In addition to precision, the researchers are also measuring the forces generated during milling. These forces remained below five Newtons in the tests – roughly equivalent to the weight of a 0.5-liter bottle of water. Furthermore, the team is investigating the system’s noise levels to better assess its suitability for practical use.

Soon with sensors and camera

However, further work is needed before the “MIR” can be used in dental practices. In the next step, the researchers plan to integrate sensors and a camera into the robot so that the system can monitor its position and the progress of the treatment. “Even after a power outage, the ‘MIR’ would know its location and where to continue based on the sensor data,” explains research group leader Prof. Dr. Georg Rauter. The goal is to keep the mini-robot from becoming any larger.

Rauter’s team regularly works closely with practicing physicians and dentists to develop robots for medical applications. The dental robot was created as part of an Innosuisse-funded project in collaboration with the Center for Dental Medicine at the University of Zurich, Camlog Biotechnologies GmbH from Basel, and the University of Bern.