Early-stage gum disease starts when bacteria are left on teeth and gums, and plaque forms. Plaque and the acids it produces irritate the gums, causing them to become red and swollen.
Plaque can harden into tartar (or calculus), a mineral buildup that also irritates gums and must be removed by a dental professional.
Untreated gingivitis can progress to advanced gum disease (periodontitis), causing gums to pull away from the teeth or recede down the root. This creates deep pockets. Plaque can grow in the pockets, further damaging the gums and breaking down bones that support the teeth.
Bone damage can loosen teeth, causing them to fall out or have to be removed.
If a woman has gum disease during pregnancy, she may be at greater risk of having a premature, low-birth-weight baby. Studies have found a direct link between heart disease and the bacteria that cause gum disease. So taking good care of your teeth and gums may have benefits beyond keeping your mouth healthy.