Sleeping with your mouth open is bad for your teeth, a study has claimed.
Researchers said dozing off without keeping your lips together is just as bad for you as gulping down a fizzy drink before bed.
This is because breathing through the mouth dries it out and leads to a lack of saliva, which usually kills the bacteria that produce acid. Because the acid level rises during the night in an open mouth, it can cause tooth decay and erosion.
The research was carried out by Otago University in New Zealand and published in the Journal of Oral Rehabilitation.
It backs up first-hand evidence from dentists that people who sleep with their mouths open have higher rates of tooth decay.
The pH level in the mouth should be neutral at 7.7, but it reduces to an acidic 6.6 if the sleeper has their mouth open, according to the study.
