Dreaming of a toothbrush indicates that you are looking for something.

Dreaming of brushing your teeth with a toothbrush indicates that you want to forget something.

Dreaming that the toothbrush breaks while brushing your teeth indicates that the dreamer may have trouble with his health, and the disease that has been cured may recur.

A new toothbrush represents new things, and use new things to update your sense of self-existence.