Saliva helps protect teeth and gums from bacteria that cause cavities and gingivitis. So a perpetually dry mouth is more susceptible to tooth decay and gum disease.
唾液可以保护牙齿免受引发牙齿腔洞和牙龈炎的细菌感染，所以长期干燥的口腔更易患这两种疾病。
2
Next time you're brushing your teeth, smear a bit of toothpaste on the bathroom mirror and wipe it dry.
下次你要刷牙的时候，往浴室的镜子上涂一点牙膏并将其擦干。
3
Hard dry food is really good for my teeth. it can help to remove the residue of food.