Gum disease is a very common condition where the gums become swollen, sore or infected.
Most adults in the UK have gum disease to some degree and most people experience it at least once. It's much less common in children.
If you have gum disease, your gums may bleed when you brush your teeth and you may have bad breath. This early stage of gum disease is known as gingivitis.
If gingivitis isn't treated, a condition called periodontitis can develop. This affects more tissues that support teeth and hold them in place.
If periodontitis isn't treated, the bone in your jaw may be damaged and small spaces can open up between the gum and teeth. Your teeth can become loose and may eventually fall out.
Read more about the symptoms of gum disease.