What’s Hiding in Your Mouth: Medical Assistant Students Investigate

Ever wonder if your pet’s mouth is dirtier than yours? That was the question students in the medical assistant program at Globe University-Madison East posed to second-graders at Cottage Grove Elementary School recently. 

Medical assistant program students in the Microbiology and Urinalysis class visited the school to work with Mrs. Riley and Mrs. Melde’s second grade class. The medical assistant program students talked to the second-graders about what bacteria is and how bacteria is found in human mouths as well as our pets’ mouths. 

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Medical assistant students (from left to right) Tiffany Milnamow, Monica Chairez, Stephanie Feinberg, and Casey Duerst pose with the pets they brought to the class.

The medical assistant students also discussed how bacteria can cause disease in humans and pets including cavities and gum disease. They stressed the importance of brushing your teeth to reduce mouth bacteria.

The Hypothesis: Brushing teeth reduces the amount of mouth bacteria in cats, dogs and humans.

The second graders were split into three groups, one group working with the cat, one with the dog, and one with a human. They conducted their experiment by collecting mouth swabs from the cat, dog, and the human before and after brushing teeth or, in the dog’s case, chewing a dental stick.The swabs were cultured onto media plates containing nutrients that support the growth of bacteria. 

Five days later, the medical assistant students returned to the second grade class with the bacterial plates and photos of the growing bacteria. They compared the amount of bacterial growth before and after tooth brushing. 

What did they find?

“We observed an obvious reduction in the amount of bacteria from the dog’s mouth after chewing the dental stick. The ‘after’ plate from the cat showed slightly reduced bacterial growth. The cat also had many bacteria that grew on selective media; these were greatly reduced by tooth brushing,” said Instructor Michelle Cotroneo. “In contrast, the human and dog samples had no growth on the selective media demonstrating differences in the strains of bacteria that inhabit a cat’s mouth.”

These findings support the notion that a cat’s mouth is dirtier than a dog’s mouth. The human samples showed no difference between the before and

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Medical assistant student Casey Duerst swabs the cat’s mouth for the experiment.

after samples, despite common knowledge that brushing and rinsing reduces mouth bacteria. 

The group discussed reasons why this part of the study did not produce the expected results and came to the conclusion that the collection technique may be to blame. They also talked about the importance of being unbiased when doing scientific experiments. 

Both the medical assistant students and the second-graders learned something through this experience. The medical assistants were able to use the knowledge they learned in their microbiology class and apply it while the second-graders learned more about bacteria.

“I thought it was fun working with the kids and animals,” said student Stephanie Feinberg.“I think they learned a lot of information about bacteria.”


For more information on the medical assistant program at Globe University, please visit our website.