Most of us know we should brush our teeth twice a day, but how should we brush? A new study has found that advice on how best to brush teeth is ‘unacceptably inconsistent'.

UK researchers assessed the advice provided by dental associations in 10 different countries, as well as advice offered by toothpaste companies, toothbrush companies and dental textbooks.

They found big inconsistencies in the advice on offer and this related to everything from how long we should brush for to what method we should use. In fact, there was a ‘worrying' lack of agreement between the advice offered in dental textbooks and the advice offered by dental associations.

"The public needs to have sound information on the best method to brush their teeth. If people hear one thing from a dental association, another from a toothbrush company and something else from their dentist, no wonder they are confused about how to brush. In this study we found an unacceptably inconsistent array of advice from different sources," commented the study's senior author, Prof Aubrey Sheiham, of University College London.

He insisted that dental associations in particular need to be consistent about what method they recommend, however the study found that worryingly, ‘the methods recommended by dental associations are not the same as the best ones mentioned in dental textbooks. There is no evidence to suggest that complicated techniques are any better than a simple gentle scrub'.

The study noted that the most commonly-recommended brushing method involves gently moving the brush back and forth in small motions, yet no large-scale studies have found this to be any better than basic scrubbing.

"Brush gently with a simple horizontal scrubbing motion, with the brush at a 45 degree angle to get to the dental plaque. To avoid brushing too hard, hold the brush with a pencil grip rather than a fist. This simple method is perfectly effective at keeping your gums healthy," Prof Sheiham said.

He emphasised that there is ‘little point' in brushing teeth after consuming sugary drinks or sweets in an attempt to prevent decay.

"It takes bacteria from food about two minutes to start producing acid, so if you brush your teeth a few minutes after eating sugary foods, the acid will have damaged the enamel," he noted.

Also commenting on the findings, the study's co-author, Dr John Wainwright, said that the reason there are so many different recommendations is probably due to the ‘lack of strong evidence suggesting that one method is conclusively better than another'.

"I advise my patients to focus their brushing on areas where plaque is most likely to collect - the biting surfaces and where the teeth and gums meet - and to use a gentle scrubbing motion. All too frequently I am asked why the method I am describing differs from how previous dentists have taught them in the past," he said.

He called for better research into ‘what the easiest to learn, most effective and safest way to brush is'.

"The current situation where not just individual dentists, but different dental organisations worldwide are all issuing different brushing guidelines isn't just confusing - it's undermining faith and trust in the profession as a whole. For something most people do twice a day, you would expect dentists to send a clearer, more unified message to their patients on how to brush their teeth," Dr Wainwright added.

Details of these findings are published in the British Dental Journal.