Asked by: Samuel Thompson, Manchester
A recent study by Prof Aubrey Sheiham and colleagues at University College London found an “unacceptably inconsistent array of advice” from dental associations, dentists and toothbrush companies.
Some dentists claim a side-to-side motion is fine, while others insist on different actions in different parts of the mouth. The most common advice is jiggling the brush back and forth. According to Sheiham, there’s no evidence any of these are better than just scrubbing. He recommends brushing from side to side, with the brush at a 45-degree angle and held lightly. He suggests focusing on where plaque is most likely to collect, which is biting surfaces and where teeth meet gums.
Subscribe to BBC Focus magazine for fascinating new Q&As every month and follow @sciencefocusQA on Twitter for your daily dose of fun science facts.