From rinsing to whitening – why you're looking after your mouth wrong

A recent lively Twitter discussion revealed, as these things often do, the existence of a group of utter barbarians: people who do not wet their toothbrush before brushing their teeth. It is almost impossible to believe such people exist, let alone that their method works, but it does. Apparently, it is a matter of preference. “A dry brush increases friction with the bristles and won’t dilute the fluoride in the toothpaste, while a wet toothbrush adds moisture and, for most people, makes the brushing experience more pleasant,” says Damien Walmsley, a scientific adviser for the British Dental Association. “Whatever your preference, what really matters is that teeth should be brushed twice a day, for at least two minutes, with a fluoride toothpaste, including last thing at night.” So, if it is not necessary to add water, what else might we rethink in the dental area?

Don’t brush straight after meals or after certain drinks

“If you eat anything with sugar or carbohydrates in it, the enzymes in the mouth create an acid,” says Derek Richards, a consultant in dental public health and the director of the Centre for Evidence-based Dentistry. This can weaken the surface of the teeth. Sugary drinks or fruit juice “will dissolve the very superficial layers of the teeth; if you brush your teeth straight away, you’re going to start brushing that [surface] away. If you want to brush your teeth straight after fruit, wait 10 minutes or rinse out with water and then brush.”

Spit, don’t rinse

“You shouldn’t rinse your mouth out after you’ve cleaned your teeth because that washes away the fluoride that helps harden your teeth,” says Richards. “Most of the real improvement in the reduction of tooth decay since the 1970s is largely down to toothpaste manufacturers and the fluoride they’ve been putting in.”

A knocked-out tooth can be saved

Sometimes. Rinse it and put it back in the socket immediately, then get to a dentist. If you can’t put it back in or can’t face doing that, put it in cow’s milk – not water – while you seek dental attention. “If it’s put in milk within five minutes, the root’s cells can be preserved for up to an hour,” says Monty Duggal, a former head of paediatric dentistry at the University of Leeds.

Good bacteria might prevent bad breath

In 2013, Scientific American reported that researchers were looking at whether supporting the mouth’s good bacteria could improve bad breath. If this is the case, antibacterial mouthwashes, which kill off all bacteria, could do more harm than good. You can buy oral probiotics, but a review last year of the small number of studies concluded that the data was “deficient”.

Don’t get your teeth whitened by a beauty therapist

It is illegal, although some unscrupulous people offer it. It is possible to buy home whitening kits online, which may conrain unsafe levels of hydrogen peroxide and cause burns or tooth loss. As long as it is carried out by a dentist, teeth whitening is considered safe.