Re: How do certain products such as sugar affect teeth.

MN:

I don't know your grade level, so I'm going to assume you are a high 
school student.

The effect of sugar on teeth is to supply food for bacteria which produce 
acids when they grow. (Sugar is chemically close to many organic acids, 
and living things convert sugars to acids and energy as part of their food 
cycles.) The acids produced from sugar metabolism eat away the enamel on 
teeth.

The acids produced include lactic acid, citric acid, propionic acid and 
acetic acid. The bacteria involved include Streptococcus species (e.g., 
mutans) and lactic acid-forming bacteria.

For there to be a problem, the following things must be present: 1) sugar, 
2) the right kind of bacteria, 3) time for the conversion.

To prevent tooth decay, you must: 1) avoid sugars and starches (similar to 
sugars), 2) remove the bacteria and acids (by brushing), 3) slow the 
growth of the bacteria, or 4) harden the enamel (by flouride treatments).

Things to investigate would include: 1) frequency of brushing, 2) amount 
of sugar, 3) time elapsed between eating sugar and brushing, 4) effect of 
antimicrobial mouthwashes, 5) effect of fluoride in toothpaste, water or 
treatments.

Listerine is a brand of mouthwash most advertised as antimicrobial. Almost 
all common toothpastes include some form of flouride. Chewing gums replace 
sugar with sorbitol or other sweetener to avoid acid generation.

See http://www.lazerdontics.com/decay.htm for a summary. 

If you wish to search the internet, I would suggest using "sugar AND 
caries" as a starting point.

An interesting science experiment would be to measure the acid formation 
and effect on teeth (or apatite, the mineral in enamel) by using different 
sugars (sucrose, dextrose, sorbitol, starch).