This Tiny Robot Dentist Fits Inside Your Mouth and Could One Day Prepare Teeth for Crowns

This one-of-a-kind miniature robot follows a digital treatment plan and could eventually reduce the need for multiple crown appointments.

If a robot can place car parts with microscopic precision on the assembly line, why shouldn’t it be able to shape a tooth for a dental crown? Engineers have imagined robots taking over some of dentistry’s most delicate tasks, but turning that idea into reality has proven far more difficult. 

Teeth sit inside a constantly moving environment. Patients shift in their chairs, tilt their heads, swallow, and adjust their jaws. Even tiny movements can matter when a dentist is removing fractions of a millimeter of material. And unlike things on the assembly line, patients tend to scream in pain when you drill in the wrong place.

So previous attempts at robotic dentistry have therefore relied on large robotic arms positioned outside the patient, forcing the machines to continually track and compensate for movement.

Recently, a team of researchers in Switzerland decided to solve the problem from a completely different angle. Instead of building a bigger and smarter robot outside the mouth, they built a smaller one that goes inside it.

The result is a prototype called the Miniature Intraoral Robot (MIR)—a device barely larger than a wine cork that attaches directly to a patient’s teeth. As it is mounted inside the mouth, it moves together with the patient rather than trying to chase every movement from afar. 

“Even if the patient turns their head, the MIR moves with them,” Yukiko Tomooka, lead study author and a postdoc researcher at the University of Basel in Switzerland, said.

The researchers believe this unusual design could eventually help automate one of dentistry’s most common procedures, which is preparing a tooth for a crown.

Shrinking the robot instead of enlarging the workspace

At first glance, putting such a complex robot with moving parts inside a human mouth sounds almost impossible. A dental crown preparation requires a cutting tool to reach multiple surfaces of a tooth while maintaining high accuracy. 

There is very little room to work, and adding motors, electronics, and cooling systems would quickly make any device too bulky. The researchers solved this problem by separating the robot’s ‘muscles’ from its ‘hands’.

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The MIR itself measures just 43 millimeters long, 26.4 millimeters wide, and 27.6 millimeters high. The motors and control hardware remain outside the patient’s mouth near the dental chair. Flexible shafts, cables, and tubes transfer movement and power to the miniature device.

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This arrangement allowed the team to keep the robot small enough to fit within the limited space available during treatment while still providing the mechanical motion needed for drilling.

The robot is designed to be attached to a custom-made splint created from a digital scan of the patient’s teeth. This personalized support holds the robot in place and allows it to move together with the patient during treatment.

As the researchers explain, “Patient movement was tracked using a 3D-printed, patient-specific splint with tracking markers, which was also used to maintain the opening of the mouth.”

Traditional external robots must constantly determine the patient’s location and adjust their movements accordingly. MIR takes a different approach: because it is attached directly to the patient’s mouth, it moves whenever the patient moves.

Turning a digital plan into a physical tooth preparation

Today, dentists typically prepare the tooth first and then take the prints needed to manufacture the final crown. This sequence often leads to additional appointments and waiting time.

The researchers envision a different workflow. A dentist would begin by scanning the tooth and creating a digital treatment plan. This plan would specify exactly how much material should be removed and from which areas.

Using that treatment plan, a laboratory could potentially begin manufacturing the final restoration before the preparation step takes place. The robot’s job would then be to execute the preplanned design as accurately as possible.

This approach makes the entire process more streamlined because the preparation and crown design would be linked from the beginning rather than being performed as separate steps.

From here, MIR performs its work in two stages. First, it uses a wider cutting bur to reduce material from the top surface. It then switches to a longer, narrower bur capable of reaching the sides.

In theory, this process sounds smooth and easy. However, in reality, the researchers weren’t sure whether such a small machine could actually remove material accurately enough for dental work. 

Testing whether a tiny machine can actually do the job

To find out, the Swiss team conducted a series of laboratory experiments using artificial dental materials and tested the system on two different materials. One was a synthetic resin commonly used in dentistry. The other was a hybrid ceramic whose hardness is closer to natural tooth enamel.

The first set of experiments focused on movement accuracy. MIR was instructed to follow a predefined path while an external optical tracking system measured its performance.

The average positioning error was 0.18 millimeters, while the largest observed error reached 0.47 millimeters. When researchers evaluated the consistency of the robot’s path rather than comparing it directly with the original plan, the average deviation fell to just 0.087 millimeters. Moreover, the robot successfully produced the intended conical shapes in both materials. 

The surprising part of the results

Perhaps the most impressive aspect of the study is what the robot does not yet have. MIR currently lacks onboard sensors that can directly measure its position while operating.

“What is remarkable is how precisely the dental robot already works, even though it does not yet have any sensors to measure or even correct its position directly. In tests, the positional error was less than 0.2 millimeters, which will be further reduced after sensors are integrated into the system,” the University of Basel team notes.

Currently, it relies on information from motor encoders located roughly 30 centimeters away from the cutting tool. Motion must travel through flexible shafts, worm gears, and lead screws before reaching the drill.

Every one of those components can introduce small inaccuracies through friction, elasticity, or mechanical play. Engineers normally expect such effects to reduce precision. Yet despite these limitations, the prototype still achieved sub-millimeter performance in its laboratory tests, which is very impressive.

This suggests the core mechanical design is already capable of a level of accuracy that may be useful for dental procedures, even before the system receives its planned upgrades.

A robot dentist is still a long way off

MIR is not yet a clinic-ready technology. So far, the robot has only been tested in laboratory conditions using dental materials that mimic real teeth. 

It has not been evaluated on real patients, where factors such as saliva, soft tissues, neighboring teeth, and limited working space could make the task far more challenging. Addressing these challenges is the next major goal. 

Future versions of MIR are expected to include onboard sensors and miniature cameras that continuously track the robot’s position and monitor the procedure’s progress. 

This would probably make the system more accurate, reliable, and safer. If these improvements prove successful, the technology could offer benefits beyond convenience. 

For instance, current crown procedures can remove up to 75.6 percent of a tooth, including some healthy tissue. The researchers believe that combining digital treatment plans with MIR-level robotic precision could help dentists remove only what is necessary, preserving more of the natural tooth. 

This could make dental procedures faster, more precise, and less dependent on repeated visits.

The study is published in the journal IEEE Transactions on Medical Robotics and Bionics.