Is a Dog Mouth Really Clear Than a Human’s Mouth?
There is a saying that a “Dog's Mouth is cleaner than a human’s mouth.” Could this be true? Could a dog’s mouth be cleaner than ours. My host sister, Lucia, who is now a veterinarian, said she would never let her dog kiss her. I didn’t care if my dog kissed me, and I never got sick. Who is right??
My hypothesis is that a human’s mouth is much cleaner than a dog. I hypothesized that dog’s mouth would have more bacteria. A dog picks up trash off the ground, eats dirt and grass, and sometimes eats our table scraps. Humans brush our teeth twice a day and eat foods that help us with oral hygiene.
In order to conduct this experiment, first I bought premade petri dishes. I left one plate as a control plate. I went over to the human and dog’s house. The human signed the release paper and agreed to let me swab their mouth as well as the dog’s mouth. I took a clean swab and dipped it into bottle water. Each time I dipped the swab, I used a new bottle of water. I swabbed the human’s mouth first. I swabbed each cheek and tongue. Then I took the swab and put it into a plastic bag that was labeled with human 1-5. I did the same for the dog, but I swabbed their tongue and gums. Then I placed their swab into a labeled plastic bag. Once I got to school I took each swab and rubbed it on the petri dish labeled with Human #1 and Dog #1. Later I identified each organism to see which has grown more bacteria, the dog or human. After eight days, I started keeping track of each organism growth from each dish by counting and sketching any growth.
My results were interesting, for all ten experiments, the human bacteria and the dog bacteria were different from each other. The human bacteria looked like grayish, small spots. The dog bacteria were more yellow or white. The total number of bacteria for the humans were 50 spots. While the number of bacteria for the dogs were 310 spots. There were most bacteria on the dog but were shapes different and looked different than the human bacteria. I think more research would be needed to know if the bacteria is a good or bad bacteria.
In conclusion, I learned that my hypothesis was correct. The dog’s mouth had grown over 100 more organisms than any of the human dishes had, proving that’s human’s mouth is cleaner than a dog’s mouth. I did see different types of bacteria on the human and dog petri dishes. “It’s like comparing apples and oranges,” says Colin Harvey, a professor of surgery and dentistry at the University of Pennsylvania’s School of Veterinary Medicine. Although there’s a vast overlap of bacteria in the mouths of both species, Harvey considers the question of which one is cleaner to be irrelevant because a) both are teeming with microbes, and b) in many cases, a dog’s dental bacteria differ from their human counterparts.
There are some ways I could improve my Science experiment, I could improve my data by doing my experiment on the same day instead of random days. Another way I could improve my experiment is by swabbing each person and dog between 3-5pm. With the different types of bacteria I could also find out which bacteria is good and which bacteria is bad.