If you breathe through your mouth while asleep, you could be unwittingly causing tooth decay.
Mouth-breathing during sleep is linked to a more acidic oral environment that may cause tooth enamel erosion and cavities, according to new research released by the University of Otago.
The study looked at the pH levels of 10 healthy volunteers, who alternated between sleeping with and without a nose clip that forced them to breathe through their mouths.
The average pH during sleep with mouth-breathing was a mildly acidic 6.6, compared to a neutral seven when nose breathing.
Lead author Joanne Choi said while volunteers' pH levels naturally decreased over hours of sleep, they showed greater falls over a longer time when they were forced to mouth-breathe.
At times, the pH levels fell as low as 3.6 during forced mouth-breathing, well below the critical threshold of 5.5 where enamel starts to deteriorate, she said.
The study was published in the Journal of Oral Rehabilitation.