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Much like flight simulators help train new pilots, the School of Dental and Oral Surgery uses simulation machines to help first- and second-year students reinforce the theoretical and practical knowledge and skills learned in class. Based on its preliminary research that showed students learn faster using simulation machines, the school in September expanded its 2-year-old dental simulation laboratory with three new machines that replaced one older model.

The computerized simulators are used in SDOS to add to the traditional laboratory-based pre-clinical training in the first and second years, before students see their first human patients at the beginning of the third year.

Students use the simulators to develop manual dexterity skills by practicing selected procedures to prepare teeth for fillings and crowns. The system, called DentSim and made by DenX America of Las Vegas, Nev., includes a patient mannequin head and partial torso, dental instruments, infrared sensors on the instruments and mannequin, an overhead infrared camera, a monitor, and two computers. Sets of plastic teeth are inserted into the mannequin's mouth so students can perform drilling and cutting techniques.

The sensors allow the computer to make a 3-D image showing where the student is drilling and if the work is correct. The machine provides constant, detailed feedback and beeps to let students know when they are doing a procedure incorrectly. For added realism, the simulation contains fictional patient records, including medical histories, X-rays, examination and diagnosis notes, and treatment plans. Each student's work is stored in the machine's computer, enabling the work to be reviewed in a video format to re-examine performance.

To determine when students benefit most from the machines, Dr. Alice Urbankova, assistant professor of clinical dentistry and director of the dental simulation laboratory, collaborated with Dr. Farhad Hadavi, professor of clinical dentistry, and Dr. Vicki LeBlanc, a cognitive psychologist formerly with Columbia's Center for Education Research and Evaluation and now an assistant professor at the University of Toronto, on three studies of SDOS students. They found that the simulators are most beneficial for students in the early stages of training on a particular set of skills. Based on those findings, students are required to use the machines in the first-year Dental Anatomy & Occlusion and Fixed Prosthodontics courses and in a second-year course, Operative Dentistry, which Dr. Hadavi leads.

Because the lab has only three simulators, the 73 first-year students are divided into groups of about six students. (The same approach is used with the 80 second-year students.) Each group is assigned three four-hour sessions on the simulators over a period of a few weeks. In those sessions, the group of six students is divided into three two-person teams to work at the machines. A faculty member supervises each session. Students also can get extra practice when no sessions are scheduled. Research on optimal use of the machines continues. The investigators seek to identify how much training with the simulator is best and the factors that make learning on the simulator better than learning through traditional instruction. SDOS also is evaluating whether it needs additional machines, which cost approximately $70,000 per unit, depending on how many are purchased at one time.

More than just a practice dummy, the apparatus can evaluate students without the biases of a human lecturer. "The machine doesn't have favorite students and judges all students in the same way," Dr. Urbankova says. So far, the DentSim machines are used for teaching purposes only, not for exams. But SDOS could use the machines for grading purposes in the future once their validity and reliability as examination tools have been assessed.

Dr. Richard Lichtenthal, Benfield Associate Professor in Operative Dentistry and director of the division of operative dentistry, says the machines help students get a better education because the machines provide a simulated "one-on-one" teaching experience. In a traditional lab, time is wasted when students have to wait for faculty to assess their work while instructors are evaluating someone else's work. Also, slower students may be reluctant to ask for help and, as a result, may fall behind. "With the machines, students get feedback whether they are ashamed or proud, which helps them learn," Dr. Lichtenthal says.

The machines have become almost commonplace at dental schools in the past few years, as about 11 of approximately 65 dental schools in North America have adopted them as educational tools, Dr. Lichtenthal says. As the technology develops further, the machines potentially could be used in place of human patients in licensing exams, Dr. Lichtenthal says. SDOS, which is one of the first schools to use the DentSim machine, is working with DenX America to improve the device and develop new software for it.

The main drawback of the apparatus is that it only simulates part of the entire procedure a dentist must do, Dr. Lichtenthal says. DentSim shows the proper way to prepare a tooth for a crown or a filling, for example, but doesn't show how to fit a crown or put in a filling. If the system were able to show the entire process, it could assist dental education greatly in light of a national shortage of dental faculty.

"The simulators can't replace experienced faculty but the machines can be effective adjuncts to a traditional dental education," Dr. Lichtenthal says.