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dental simulator with Jennifer Day

Dental student Jennifer Day checks her drilling technique on a new advanced simulation unit.

They know the drill

Computerized mannequins give dental students instant feedback

By Deane Morrison

Bending over the wide-open mouth below her, a second-year dental student begins to drill a tooth. Everything is going smoothly when a beep sounds. Then another. And another. Oops. She was slumping. The student corrects her position and goes on, confident she'll get no complaints from the patient. But she'll get plenty of feedback. The patient is a mannequin in the School of Dentistry's advanced simulation lab, equipped with 3-D motion detectors and an overhead screen that displays an image of the tooth and how closely the student's drilling matches the target area. It's one of 20 simulators on which all University of Minnesota dental students will soon practice drilling, getting instant feedback not only on how accurately they're cutting--as dentists call it--but also on their all-important body position. The University's is the first dental school in the Big Ten, and one of only a handful nationwide, to acquire such technology. Instant feedback means more practice for students who will no longer have to wait for an instructor to come evaluate them. That kind of repetition is welcome in a field where sculpting a tooth must be precise to within a tenth of a millimeter.

Tour the lab

Take a virtual tour of the University of Minnesota School of Dentistry Simulation Clinic.

"It's mostly to develop psychomotor skills," says Judith Buchanan, associate dean for academic affairs. "We want them to see patients as early as possible, so that they get as much real patient experience as they can while they're here." It helps, too, that a simulator's comments appear on the unit's overhead screen. With units arranged in groups of four, all at right angles to each other, students get feedback, and even grades, on their work in relative privacy.

Not so easy

The technology rests on two sets of light-emitting diodes (LEDs). Seven LEDs beam from an immobile hook in the mannequin's mouth, and 16 others are arranged around the handpiece (drill). A computer keeps track of where the LEDs are in relation to each other and figures out the position of the handpiece and, thus, the drill head at the end of it. A trial run in one of the simulators generates an appreciation for the skills of a good dentist, as this intrepid reporter found out. It starts with donning latex gloves and holding the handpiece over a molar, then looking up at the screen to see a diagram of the tooth with an outline indicating the area to be drilled. So far so good. I step on the pedal and hear the hum of the drill but feel no vibrations to rock the steadiness of its touch. Gently applying the drill to the molar surface, I ... hold on, what's this water doing on the tooth? Oh. Cooling the drill, of course. But how can anybody see what they're doing through a puddle of water? So I do my best and then look up at the screen.

"A play-by-play on the screen that corrects your mistakes as you go is really great because then you don't get into bad habits."--Katie Daniels, dental student.

Not bad. The computer has superimposed an outline of the area I drilled on the ideal and rated the job at 77, a passing grade. I drill a little more, trying to move the drill to trace the outline on the screen. My score rises to 80, a solid B-minus. "There are still some caries left. That's what those colored spots [on the tooth diagram] mean," Buchanan says. "You have to drill a little deeper." I go for it, stabbing here and there, trying to hit the exact places on the diagram. Suddenly, the resistance to the drill drops to nothing--and so does my grade. I've drilled too deep. Dentistry is even harder than it looks.

Students rave

The first practice on the simulators can't come too soon for students. "I really like it, especially when it tells you whether you're sitting correctly," says Katie Daniels, one of several then-second-year students who got an early chance to try their hand on the simulator. "Ergonomics is important in dentistry. A play-by-play on the screen that corrects your mistakes as you go is really great because then you don't get into bad habits." The screen can display the practice tooth as a whole and in cross section from all angles, revealing in detail how well the students are doing. "It gives you a new perspective," says Jennifer Day. "It shows you what the tooth being worked on looks like and what it's supposed to be as the cutting proceeds." University dental students are already working on restorative procedures in a lab with 100 workstations, each equipped with a mannequin, dental tools, and a flat screen for viewing live demonstrations up close. But only the advanced simulation lab has the feedback feature. "There are times in the other lab when you think you're doing it right, but you may not be because there's no instructor there at the moment," says student Grant Collins. The class of 2012 is the first class to reap a full four years' benefit from the advanced simulation. But these young students won't be the only ones using the mannequins for practice. The simulation laboratory serves graduates of dental schools outside the United States and Canada through the School of Dentistry's Program for Advanced Standing Students (PASS). In general, in order to stand for a U.S. licensing exam, foreign-trained dentists must have two years of training in a U.S. dental school, which PASS provides. In 2008, 11 PASS students came from Egypt, Nigeria, Bhutan, and other countries to start on the road to practicing in this country. And graduation won't mean the end of visits to the lab for dental students. "Alumni will want to come back just to try their hand on this new equipment," says Patrick Lloyd, dean of the School of Dentistry. "It's like nothing they've ever seen before."