Periodontal disease is the medical term for gum disease. Although there are several risk factors for developing gum disease (including smoking, certain medications, and even your genetic makeup), the main cause of gum disease is the bacteria living in your mouth. These bacteria form a layer on the teeth called plaque. With good brushing and flossing, you can remove a lot of this plaque. But if you don't brush and floss regularly, the plaque hardens into a substance called tartar.
Bacteria and tartar can lead to gum inflammation. The medical term for this is gingitivitis, and it is the earliest (and mildest) form of periodontal disease. It can often be treated just by going back to good dental habits and having regular cleanings at your dentist's office.
If you have gingivitis but don't get it treated, the gum disease can get worse. You could go from having gingivitis to having periodontitis (inflammation in the areas around the teeth). At this stage of gum disease, the bacteria living in your mouth infect the areas below your gum line and into your bone. Your teeth may loosen and may even have to be removed.
At the more advanced stages of gum disease, brushing and flossing are not enough to treat the disease. You may need to have special cleaning procedures called deep cleaning, take medications, or even undergo surgery. If you think you are at risk for gum disease, talk to your dentist. He or she will give you the information you need to keep you and your mouth as healthy as possible.