A biopsy is a surgical procedure done to either remove (entirely or partially) a lesion, in order to be able to use a microscope to definitively diagnose what it in fact is.

If you have a suspicious growth in your mouth, it may need to be cut out in order to rule out any oral pathology, such as cancer.

Biopsies can be done in many ways, such as excisional (remove entire lesion) or incisional (remove part of the lesion).

If there is a lesion in your bone, definitive excision or biopsy may be necessary. Just because you are having a biopsy, do not automatically worry about cancer. That bump on your gum may be nothing more than a common wart. Depending on its appearance, often times you can ask your dentist if cancer is suspected.