Dentists can tell if someone vapes by looking for several telltale signs. These signs include dry mouth, which is caused by the vaping e-liquid's propylene glycol and vegetable glycerin ingredients. Vaping can also cause gum inflammation and receding gums due to the nicotine and other chemicals in the vapor.
In addition, dentists may notice tooth decay and cavities in vapers. This is because the sugar in e-liquids can feed bacteria in the mouth, leading to cavities. Vaping can also cause teeth to become stained and discolored.