Don’t sleep with your mouth open – it can rot your teeth

SLEEPING with your mouth open isn’t just unsightly – it can also cause tooth decay, a study has found.

Breathing through your mouth rather than your nose when asleep can be as bad as bathing your teeth in fizzy drinks before bed, scientists say.

This is because acid levels in the mouth rise as saliva dries out, leading to tooth erosion.

A team led by sleep researcher Joanne Choi at Otago University in New Zealand recorded the acidity levels of the mouths of ten volunteers, who slept while wear- ing nose clamps, forcing them to breathe through their mouths.

They found that under normal conditions, the PH level in the mouth is a neutral level of 7.7.

But sleeping with your mouth open, makes it mildly acidic with an average PH of 6.6, according to the study published in the Journal of Oral Rehabilitation.

And in some, the PH level was 3.6 – acidic enough to erode tooth enamel and akin to having a fizzy drink before going to bed. The reason breathing through the mouth causes acidity is thought to be because it dries out saliva, which normally kills bacteria that produce teeth-decaying acid.

The research is more likely to affect men. Previous studies have shown that nearly a third of British men breathe through their mouths at night, compared with just 5 per cent of women.

Miss Choi said: ‘Our findings support the idea that mouthbreathing may indeed be a causal factor for dental diseases such as enamel erosion and caries.’