I interviewed Jennie M. Fleming, RDH, BS, MEd, Dental Prevention Coordinator for the East Metro Health District in Lawrenceville, Georgia. I asked her about toothpaste. 
 

1) Would there be a difference if toothpaste was not invented?
Not necessarily, throughout centuries, people have brushed their teeth using water, baking soda, salt, and even a few have brushed with cologne.

2) What exactly does fluoride do?
Fluoride is used to to protect the enamel, if it doesn't protect the enamel acid can flow into the passageways causing cavities. 

3) How many times should you brush your teeth?
It depends on how well a person brushes. Some people need to brush after every meal.

4) Is it true that you have to brush twice a day, if you do, why?
This depends on someone's diet, people can usually get by brushing 2 times a day.

5) If you use other products for your teeth and you also use toothpaste is it toothpaste or the other product that makes your teeth whiter?
With other product  your teeth may be discolored, some over- the - counter products are too strong and can damage the tooth enamel and gum tissues. Toothpaste is just designed to help you brush easier, as long as you brush properly, your teeth should remain their natural color.

Check out these websites for some really great information.

Dental Reference:  www.dentalreference.com

Ms. Flossy:  http://www.ms-flossy.com

Floss Boss at:   http://www.geocities.com/HotSprings/Spa/9781/

Smiley's Children's site:  http://www.ms-flossy.com/sindex.html

Colgate general information:  http://www.colgate.com/oralhealth/topics/child.htm

Amreican Denytal Hygienists' Association:   www.adha.org

CDC's Oral Health website:  http://www.cdc.gov/oralhealth/topics/child.htm

American Dental Association:   www.ada.org