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Staining Teeth with Beverages

Staining Teeth with Beverages

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Science Fair Project Description

This science fair project was performed to compare the amount of stains left on our teeth by the beverages we drink. The tests were done by comparing the effects of coffee, tea, grape juice and Coca-Cola, when exposed to tooth enamel.
Complexity level:3
Project cost ($):50
Time required:1 hour for preparation, 1 hour for the science fair project experiment
Material availability:A dentist might be able to provide the teeth required for this experiment
Safety concerns:None


Coffee will leave the most stains on our teeth.


Teeth staining

The natural color of our teeth is light grey or light yellow. Teeth whitening solutions can help our teeth become whiter. However, some of the food and beverages we consume daily can stain and discolor our teeth.

There are two types of teeth stains, namely intrinsic stain or extrinsic stain. Intrinsic stains are caused by age, malnutrition, infections or genetic reasons. Extrinsic stains are more manageable. They are caused by the food and beverages that we consume. These stains are merely cosmetic and can be removed by proper dental care.

The staining of our teeth due to plaque can be easily removed by regular brushing, flossing and visiting the dentist. Food that leaves stains on our teeth includes berries, soy sauce, chili sauce and curries. Beverages that leave stains are coffee, tea or coke. These stains can also be easily removed by brushing our teeth.

Scientific Terms

Teeth whitening, intrinsic stains, extrinsic stains, malnutrition


The materials required for this science fair project:

-    5 teeth
-    1 cup of coffee
-    1 cup of tea
-    1 cup of grape juice
-    1 cup of red wine
-    1 cup of Coca-Cola
-    1 toothbrush and 1 tube of toothpaste
-    1 sheet of paper
-    1 black marker
-    1 stopwatch


1.    For this science fair project, the independent variable is the type of beverage used to stain the teeth. The dependent variable is the degree of staining on the tooth. This is determined by comparing the stains on the teeth after removing them from the beverages. The constants (control variables) are the temperature of the beverages, the whiteness of the teeth used and time the teeth are left in the cup.

2.    Brush the 5 loose teeth with the toothbrush and toothpaste until all the teeth reach a similar color.

3.    Fill 5 cups with coffee, tea, grape juice, red wine and Coca-Cola. Drop a tooth into each cup and set aside for 3 minutes. Then, remove the teeth, wipe dry, and place on a sheet of  paper. Label each tooth for the beverage it was placed in.

4.    Compare the discoloration and staining on each tooth. Rank the teeth according the degree of staining, with 1 being the most discolored and 5 being the last discolored.


The results show that the grape juice caused the most staining, while the red wine had the least staining effect on the teeth.


Beverage Coffee Tea Grape juice Red wine Coca Cola
Tooth stain rating 3 4 1 5 2


The hypothesis that coffee will leave the most stains on our teeth has not been proven to be true; instead, grape juice caused the most discoloration.

Having a beautiful smile and white teeth is important to a lot of people. Many people visit dentists to obtain cosmetic whitening for discolored teeth. There are also a lot of teeth whitening products available in the market. Having stained teeth may be embarrassing to some and may affect their self-confidence; hence, it may be advisable to drink in moderation beverages known to stain teeth.

Also consider

The science fair project may be repeated using different types of food like soy sauce, curry, black pepper sauce or chili sauce.

The experiment may also be done to compare stains left on fabric by food or beverages.


Teeth stains and discoloration -

Foods and drinks that stain your teeth -

Related videos

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