Are Dog Mouths Cleaner Than Human Mouths?
It's a common misconception that dog mouths are cleaner than human mouths. Both mouths are hosts to hundreds of kinds of bacteria, most of which are species-specific. There's only about a 16% overlap of oral microorganisms between dogs and humans, so there's no such thing as comparable, objective "cleanliness" with regards to their mouths.
Key Facts In This Video
Dog mouths are not cleaner than human mouths, as both mouths contain species-specific bacteria. (0:43)
One 2015 study found that oral-to-oral transfer of bacteria from dogs to humans can cause gingivitis and periodontal disease. (1:14)
You're more likely to catch an infection by swapping saliva with another human than with a dog. (2:37)