Oral bacteria and mouthwash

[deleted-798917]

My daughter will be testing 3 different mouthwashes to see how they effect oral bacteria. Would the best way be to do a control dish, then ear something, rinse w the mouthwash and swab. Then brush, eat something, rinse and swab. Or should we swab the mouth and put on the Petri dish, then soak the disk in the mouthwash and place on the dish? Trying to decide which method is best and then how to show or measure data. Thank you.

[deleted-739703]

Wow, this is a neat experiment!

This is a tricky one because once you use one mouthwash, the chemistry of your mouth will not be the same. Definitely use the mouthwash as intended rather than outside of your mouth. Also make sure to eat the same food every time and use the mouthwash for the same amount of time every trial.

One process you could try is
1) eat
2) wait a certain amount of time (maybe an hour?) (this will allow bacteria levels to become more natural)
3) rinse with water
4) use mouthwash (omit this step for a control trial)
5) swab
6) repeat

Others may have other ideas. Good luck with this!

-Emma

[deleted-798917]

Thank you! Yes that was the plan. Waiting a few hours between and eating the exact same thing. Should we brush, eat and then rinse? And do you know how to show data for the bacteria growth? We won’t use a microscope so i am not sure how we will do that? Thanks again

[deleted-674917]

This a great idea, Parnelly!
Emma has already detailed a step by step protocol which sounds great to me as long as you follow the precautions she mentioned.

Regarding the bacterial count - do you have access to petri plates? You could transfer the oral bacteria from the swabs to the agar surface and count colonies. Bacterial numbers can be measured by growing in liquid growth medium too (LB broth for example) but that would also require an instrument called spectrophotometer to assess turbidity or at least a microscope to count cell density.

Good luck and please reach out again if you have additional questions!
MS