Researchers at the University of Basel have developed a miniature robot designed to prepare teeth for dental crowns according to a digital treatment plan. The prototype could reduce the number of appointments required for crown procedures, although further development is needed before it can be used in clinical practice. The device, called the Miniature Intraoral Robot, or MIR, measures 43 by 26 by 28 millimetres, approximately the size of a wine cork. Its motors and control system are located outside the robot and connected through flexible drive shafts, cables and tubes.
“It is designed to be small enough to fit comfortably into an open mouth,” said Yukiko Tomooka, first author of a paper describing the system in the journal IEEE Transactions on Medical Robotics and Bionics. Crown treatment typically involves removing decayed material, preparing the remaining tooth, taking an impression and fitting a temporary crown. A permanent crown is then manufactured and placed during a later appointment.
Under the proposed approach, a dentist would scan the patient’s teeth and use the resulting data to plan how much material the robot should remove. The same scan could be used to order the crown and manufacture a custom dental splint to which the robot would be attached. Because the splint is fitted to the patient, the device would move with the patient’s head during treatment.
The researchers tested MIR on tooth models made from synthetic resin and on a ceramic material with hardness comparable to tooth enamel. The robot carried out the preparation in two stages, using a wide drill to remove material from the upper surface before applying a longer, thinner drill to the sides of the tooth.
The prototype recorded a positional error of less than 0.2 millimetres despite lacking sensors that could directly measure or correct its position. The researchers said they intend to reduce the error by adding sensors to the system. Drilling forces remained below five newtons during testing. The team is also assessing the noise generated by the device as part of its evaluation for potential use in dental practices.
The next stage of development will involve integrating sensors and a camera so the robot can track its position and monitor treatment progress. The researchers aim to add these components without increasing the size of the device. “Even after a power outage, MIR would know where it is and where it needs to continue based on the sensor data,” said research group leader Georg Rauter. The project was carried out with the Center for Dentistry at the University of Zurich, Camlog Biotechnologies GmbH and the University of Bern, with funding from Swiss innovation agency Innosuisse.
Foto credit: University of Basel, Catherine Weyer
