To find out just who has a cleaner mouth, we asked veterinarian and fellow dog lover Marty Becker, author of "Chicken Soup for the Dog Owner's Soul," to offer his opinion.
"They raid the garbage can. You know, we give each other a peck on the cheek when we say hello, they give each other a peck on the rear end," said Becker. "All you got to do is look, watch, smell and you'll realize that that is not true."
He thinks the myth that a dog's mouth is clean stems from their practice of licking their wounds.
"And they'll be licking that wound and you'll notice that the wound heals very fast … what that tongue does is it gets rid of the dead tissue," said Becker.
He compares that tongue lashing to the work of a surgeon who cleans out a wound, and said the licking also stimulates circulation.