What is a cavity? 20 characters ?!

Its bacteria on your tooth (plaque), which uses the food you eat to survive and produce acids that erode the minerals from your teeth - leaving a soggy organic mass behind.
You have enamel (hard outer layer), dentine (middle layer with tubules - small channels), and pulp tissue at the centre of your tooth (centre layer contains nerves). When you have tooth decay (described above), the enamel has been eroded, so the dentine tubules are open to the outside (in simple terms). The sugar sucks water away from these tubules - and the change in pressure within these tubules causes the nerve in the pulp to be irritated - hence pain.

Ok wow Cavity is hole in your tooth or a black spot or something caused by tooth decay and plaque which is another form of tooth decay decay gets your teeth and builds up a cavity and sugar causes cavities cause of the sugar amount of the causing bacteria and bacteria forms hole or pain and causing the systems of forming a cavity cause sugar makes plaque build up you need to be brushing your teeth 2 times a day for 2 minutes and floss at least once day and its only an infection if there is severe pain and which cause a tootache which cause a sort of form of a Cavity if it was dead your tooth would have no good tissue and the tooth would need to be pulled or have a root canal and if its an ifections you will see some white kind stuff telling your tooth could have some kind of infection why does sugar hurt our teeth well it causes cavities thats why i hope that answers your question

a hole in the tooth, cave... cavity.

www.dictionary.com

sheesh! kids these days!
do you need someone to chew your food for you too?!

I'm not a kid. I know what a cavity what I'm asking is how its created and why it hurts. I know insects not teeth.

Moron homo sapien

A hole!!!!!!!!!!!!!!!