Dentists learn with virtual drill

To the high-pitched sound of numerous drills, students get to work removing a decayed tooth.

Their patients need not be afraid though, as these want-to-be dentists are practising on 3D virtual-reality jaws, not the real thing.

The 14 work stations lined up in a lab at Europe's largest dental school, King's College London, use a technology that allows the student to learn how much pressure they should use when drilling.

The device, called HapTEL (haptics in technology-enhanced learning), received the excellence in education innovation award at the Medical Futures ceremony earlier this month.

The project is a collaboration between dentists from Guy's Hospital, technical developers from Reading University and Birmingham City University, and e-learning professionals from King's College London.

How it works

The virtual-reality jaw opens wide for a student to develop his skills.

The drill is based on haptics, a tactile feedback technology through which the user can sense touch and force in a virtual-reality environment.

The hub at the centre of the work station is based on that used in the gaming industry.

A foot pedal, recycled from an old dental chair, allows the student to operate the drill.

The work station lets the student feel the difference between drilling hard enamel and softer decayed tooth and helps them learn how much pressure is needed.

Prof Margaret Cox, who led the project, says: "When the students first learn, they lean very heavily on the drill and go straight through the tooth to the gum - which would be disastrous in a real patient. They also take ages. This allows the student to learn both skill and speed."

The student wears glasses that produce a 3D jaw on the computer screen. Panels on the edge of the glasses, and a head tracking camera, allow the jaw image to move relative to the student's head position, allowing them the real-world experience of examining the teeth from different angles.

Sadhvik Vijay, a second year student, says: "When you first come into dentistry everything is very alien to you, the way you position your hand, the tiny movements that you need to perform procedures - it is difficult.

"This allows you to repeat a task over and over again, it gets ingrained into your muscle memory, and improves your manual dexterity."

Stepping up the game

Students start by learning to remove a small bit of decayed material from a single tooth. The tasks then become more complex until they are removing decayed material hidden by healthy enamel set in a whole jaw.

Once the task is finished, the student can play back a video to examine their technique and they are told how much decayed versus healthy tooth they have removed.

"It is quite exciting as the students get competitive and discuss it with each other, 'I removed only 1% of healthy tooth, how much did you remove?' It gets them to really think what they are aiming for," says Prof Cox.

"If the student has difficulty they can look back at the pressure and angle they used to find out why they went wrong. The device has taught them to become more self-critical and that skill is just as important as the manipulation."

The cost of teeth

Traditionally, students have developed their dexterity on a "phantom head", a mannequin with plastic teeth.

Prof Cox says the advantage the hapTEL work station has over this is instant analysis and re-enactment of the task, as well as being able to practise on a tooth again and again.

One hapTEL device costs £10,000, compared with the £30,000- £40,000 price of a "phantom head" chair.

The more traditional way of learning - plastic teeth and mannequins

In addition to this are the plastic teeth. Those with all the different densities required for teaching cost £16 each.

"One student can get through a plastic tooth in five minutes, which is then thrown out. It comes to hundreds of thousands of pounds, just for the teeth which we have to buy.

"With the hapTEL, students just press a button and a new tooth appears - it doesn't cost anything more," says Prof Cox.

From class to clinic

To become a dentist takes five years. Alongside the manipulation and clinical skills, the student learns the theory and how to communicate with a patient.

In the middle of their second year they get their "licence to cut", where they work with real patients under the guidance and advice of a qualified dentist. Their patients are volunteers, who receive free healthcare for their bravery.

Before injecting a patient, students master the technique on rubber, dead animals and then each other.

Prof Cox would like to see the work stations help develop this skill.

She says: "It would mean more work to the haptic device to produce the tensions experienced when you put a needle in and when you pull it out - to which the skin still hangs on."

She adds: "We would also like to use it for simulating crown preparations. This would require the feel of a different drill head.

"If we wanted, when a student drilled through the gum we could have blood pouring out. But we have to focus on what the dentists want us to do first."

Currently the work station is a development system, with each unit having to be made and calibrated individually.

During lab time technicians are available to help with software glitches.

It is hoped that eventually it will become a plug-and-play system allowing students to practise in the library or for dentists to brush up on their skills at home.