I have always had this re-occuring dream that my teeth are falling out. Is this just a fear or can it be interpretted as something else?

This is a very common dream, it's often interpreted to be something to do with learning, nothing to do with a fear of losing your teeth. Are you finding learning something hard, or maybe there are some skills that you wish you had but don't?

Depending on what book you read this can also be interpreted as going to gain money or a fear of something that's happening in your every day life.

Losing your teeth can mean you are afraid of losing something that you won't be able to get back or a fear of losing power.

It could also mean that you have been thinking about your teeth a lot...

If you had a recent dentist appointment
If you had/have braces
If you had the dream once and it stuck in your mind and you think about it before you go to sleep
If you watched a movie where someone got their teeth knocked out

Dreams are usually a result of something we are thinking of or have experienced. That's why scary movies give us bad dreams, why pregnant woman dream about babies, brides about their weddings, and so on.