Are you a piston or a foamer?

There's more to teethbrushing than in, out, spit. Roger Dobson on an pounds 86,000 research project

VOLUNTEERS are being paid pounds 2.50 an hour to smile and brush their teeth as part of a research project which could revolutionise the shape of tooth- brushes. All the accepted styles of brushing, from the aggressive "foamers", who whip toothpaste into a lather by vigorous circular motions for a minute or more, to the lethargic "pistons", who simply brush in and out for a short period of time, are being analysed by a team of academics.

The psychologists at the University of Wales, Bangor, have been given an pounds 86,000 grant to study the way people brush their teeth using infra- red markers and cameras to chart the motion of the brush inside the mouth.

No one, it seems, really knows how people steer their toothbrushes once they are inside. All previous attempts to solve this mystery have failed because of the high volume of foam created during brushing which has obscured academics' view.

But now Dr Steve Jackson, who is carrying out the research with funding from Unilever, has developed a way of closely monitoring the movements of the brushes inside the mouth. "We are using infra-red motion analysis," said Dr Jackson, lecturer in neuropsychology. "We ask the volunteers to brush their teeth for a minute at a time and the brush has an infra-red marker on it. There is another marker on the top of their head, and with the cameras we record the movement of the brush relative to the head."

He added, "It is very important, and will provide valuable information about the design of toothbrushes. People typically don't brush their teeth properly. If they don't, what can you do from a design point of view, either to make them brush for longer, or to maximise the effect of the time they spend. It may also be that people are not brushing all of their teeth, and that too has implications for design."

Provisional findings are that people brush their teeth in circles. "What they're doing is making small circular movements, and it is very repetitive," said Dr Jackson. As part of the project, the team will be looking at prototype designs. "We will be testing and validating some prototype designs with different angles of brush, different shapes of the head and so on," he said. "We will also use variations in composition of toothpaste to see if that effects efficiency."

About 30-40 volunteers will be needed, and will get travelling expenses as well as their pounds 2.50 an hour fee. Brushes and paste are supplied. They only thing they need to provide is their teeth, preferably their own.