TWO MINUTE BRUSHING HELPS ACHIEVE CLEANER TEETH: STUDY

NEW YORK (Reuters Health) - Although hard work tends to pay off in other areas of life, forceful toothbrushing appears to be no better at ridding the mouth of plaque than a medium effort.

A group of European researchers discovered that the most efficient means of reducing plaque appears to be brushing for about two minutes at a medium force.

More vigorous teeth cleaning may actually do more harm than good, said Dr. Peter A. Heasman of the University of Newcastle upon Tyne, UK. Research suggests that heavy brushing can damage gums and wear down teeth, both potentially serious oral health problems, he said.

"Although we found that you have to brush your teeth reasonably long and hard to get rid of the harmful plaque which causes dental diseases, our research shows that once you go beyond a certain point you aren't being any more effective," Heasman said in a statement.

"You could actually be harming your gums and possibly your teeth," he added.

Heasman and his colleagues designed the study, published in the Journal of Clinical Periodontology, to determine the most efficient way to brush away plaque. Plaque is a sticky substance that can contain more than 300 species of bacteria, which adhere to tooth surfaces and produce cavity-causing acid. Plaque is a leading cause of gum disease.

During the study, Heasman and his colleagues measured plaque levels in the mouths of 12 people after they brushed their teeth using four different forces and for four periods of time -- 30 seconds, 60 seconds, 120 seconds, and 180 seconds.

The study participants brushed using a power toothbrush, which exerted set forces of between 75 grams and 300 grams. All spent 24 hours without cleaning their teeth before testing how well each technique stripped their mouths of plaque.

Heasman said that a force of 75 grams feels much lighter than one of 300 grams. However, he recommended that people visit their dentist to determine how different brushing forces feel.

"It is very difficult for a lay person to differentiate between brushing forces," Heasman told Reuters Health.

Longer brushing generally appeared better, but the researchers found that 120 seconds of brushing was roughly just as effective at removing plaque as longer brushing. And during those longer sessions, people removed about the same amount of plaque using a force of 150 grams as when they employed forces of 225 and 300 grams.

Although different people may require more or less time to get at all the plaque-ridden nooks and crannies in their mouth, spending around two minutes brushing your teeth seems "about right", Heasman said.

And applying a force beyond 150 grams -- somewhere in between light and forceful brushing -- "offered little benefit to plaque removal," Heasman added.

Furthermore, in toothbrushing, it is possible to have too much of a good thing, the researcher said.

"In the short term, gum changes may become apparent, but in the longer term, tooth wear or toothbrush abrasion is likely with too abrasive a technique, toothpaste, brush or force," Heasman said.

SOURCE: Journal of Clinical Periodontology 2003;30:409-413.