New research has found that vaping, unlike smoking, does not stain teeth.

Scientists exposed enamel to smoke from cigarettes, heat-not-burn products and e-cigarettes in an investigation believed to be the first of its kind.

Researchers found enamel exposed to e-cigarettes and heat-not-burn products is no more stained than the teeth of non-smokers.

Whereas cigarette smoke causes significant discolouration or yellowing after just two weeks of smoking one pack of cigarettes a day, the research shows.

This image shows the effects of cigarettes (top line), HNB products (middle row) and e-cigarettes (bottom row). Of all three, e-cigarettes proved to be the least harmful to tooth enamel. (Credit: BAT)

To mimic conditions in the human mouth, enamel was extracted from the teeth of cows and soaked in saliva to form the protective layer that normally surrounds teeth.

The enamel was then exposed to chemicals found in cigarettes, e-cigarettes and HNB products for two weeks.

The findings were published in the American Journal of Dentistry, and the research was led by scientists at British American Tobacco.