Which drink stains your teeth more and in which ...

I don't know for sure, but I would guess: Coffee, red wine and then coke. I think that you should get a 3 different test subjects, but make sure that they have the same color teeth to begin with.

I don't think that she will get the results that she wants having people drink the beverages.  People drink differently and they have different exposure of their teeth to the liquids. Also, you would have to make sure that they have the same color teeth to begin with. Try this:  Call a friendly dentist in your area, especially an oral surgeon.  They usually have teeth that they save so students can have them.  Ask for front top teeth if possible because they are the easiest to work with.  Get a small glass of cola, tea, coffee, red wine and tomato juice.  cover half of each tooth with some dental wax (the kind that they use for braces-get it at the drug store)  Put each tooth in the beverage and wait for seven days.  After seven days, take the teeth out, and observe your answer.  I hope she still has time to do this. 

I have found this article useful on this topic. Hope this will work for you:

Teeth discoloration and Teeth Stains

Hi,

As your question's answer,I just to share one web page which has many articles on dental.

I got few days ago from mine one of the dentists friend at facebook.

Just Visit,

Teeth Whitening

-- Teeth Whitening Gel | Teeth Whitening Kits

coffee has the much cafine and affects much more than coke and red wine.

I don't think red wine is even responsible for teeth strains

I really can't answer your question but I did find this site earlier tonight:

http://teethcleaning.info

Decent site.