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Bacteria in your toothbrushFeatured science projectScience project video


This science fair project was done to find out the best way of reducing bacteria in toothbrush. The science project experiment involved using and keeping the toothbrush in different conditions.


The toothbrush kept in Listerine solution will have the least bacteria.

Scientific Terms

Micro-organisms, bacteria, fungi, viruses, protozoa, microbes


Mouth bacteria

Our mouth is filled with plenty of micro-organisms like bacteria, protozoa, fungi and viruses. They are found in the walls of our mouth, our tongue, throat and all the way down to our stomach and intestines. Most of these microbes are harmless and they find our body to be very hospitable.

It is estimated that there are about 60 types of microbes out of about 100million of them in 1 milliliter of saliva. Most of these bacteria are swallowed by us together with the food and water that we consume. However, most of them are killed by the enzymes in our stomach and in our saliva

Some of the common types of bacteria in our mouth are Streptococcus mutans and Porphyromonas gingivalis. Streptococcus mutans are responsible for tooth decay by producing acids that will dissolve the enamel when they digest sugar and starch that are sticking to the teeth. Porphyromonas gingivalis are responsible for gum diseases.


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Complexity level:
Project cost ($):
Time required:
5 days to prepare, 5 days for science fair project
Material availability:
Easily found
Safety concerns:

Basic safety requirements