Perhaps part of the reason the idea that “a dog's mouth is cleaner than a human's mouth” came to be so widely believed is that we don't typically swap diseases with our dogs when we swap saliva. You are not going to get the flu from a dog kiss, but you might get it from kissing a human loved one. read more
While it’s true that a dog bite is unlikely to transmit any diseases to humans, other than rabies, it’s false that dogs have “clean” mouths. Infection is a risk, due to all the bacteria, same as it would be if a human bit (or licked) you. read more
Some people say that a dog’s mouth is cleaner than a human’s mouth is, but the mouths of both species certainly have what is called “natural flora”. These are bacteria that live inside the mouth and seldom cause any type of issue for the host. read more