Periodontitis
Periodontitis literally means "inflammation around the tooth". It occurs if gingivitis becomes worse and progresses to involve the tissue that joins the teeth to the gums (the periodontium), and/or the supporting bone.

As a consequence of periodontitis, a gap (pocket) develops between the tooth and gum. If left untreated, the tooth may slowly loosen and eventually fall out.

Dentists assess the severity of periodontitis by measuring the depth of the pockets that form between the gum and tooth.

Plaque can be removed from shallow pockets (up to about 3 mm deep) by brushing teeth in a normal way. However, deeper pockets need to be treated by a dentist as normal brushing will not reach the bottom of the pocket.

The rest of this leaflet is about plaque, and plaque-associated gum disease (plaque-associated gingivitis and plaque-associated periodontitis). There are other uncommon types and causes of gingivitis and periodontitis which are not dealt with further.

How common is plaque and plaque-associated gum disease?
They are very common. Surveys in the UK in the late 1990s found that:

Plaque and/or calculus was visible in more than 7 in 10 adults who had teeth.

Plaque was visible in just over 4 in 10 of those aged 15–18.

Some degree of gingivitis was present in more than half of adults and in about 4 in 10 of those aged 15–18.

Periodontitis with pocketing was present in about half of adults and in nearly 2 in 10 of those aged 15–18. Most cases of periodontitis were 'moderate' with pockets up to 4-5 mm deep. However, 8 in 100 adults were found to have severe periodontitis with pockets 6 mm or deeper.

What causes plaque-associated gum disease?
Most people develop some dental plaque, but not everyone with plaque develops gum disease. Dental plaque contains many different types of bacteria (germs) and some types of bacteria are associated with developing gum disease. The gums can often resist, or limit, the invasion of bacteria. It is thought that a more marked gingivitis, which leads to periodontitis, is more likely to develop if you have a lot of plaque and/or your defence or resistance against bacteria is reduced in some way.

The following increase your risk of developing marked plaque-associated gum disease:

Poor oral hygiene when a lot of plaque and large numbers of bacteria build up.

Smoking (which may alter your resistance to gum infection).

If you have a poor immune system. For example, if you have an illness which makes your immune system less effective, or if you are on chemotherapy, etc.

If you have diabetes.

What are the symptoms of plaque-associated gum disease?

Mild gingivitis does not cause any symptoms and so you may not realise that you have it. The gums look slightly swollen and reddened.

Moderate gingivitis can cause more marked swelling and reddening of the gums. The gums often bleed a little when you clean your teeth. Discomfort or pain from the gums is rare if you only have gingivitis.

Periodontitis often does not cause any symptoms until an affected tooth becomes loose. However, in some cases, symptoms develop and may include:

• halitosis (bad breath)
• a foul taste in your mouth
• some pus formation in small pockets between teeth and gums
• pain and difficulty eating
• affected teeth becoming loose and eventually falling out if not treated.