What is Periodontal Disease?
Periodontal disease is an infection of the gums and/or bone that surrounds the tooth. Generally the disease is painless, and most patients are not aware they have a problem until examined by a dentist.

With a healthy tooth, the root is set in the jawbone with a strong ligament, which keeps the tooth tightly attached to the bone. Gum covers the bone, and like skin, protects it from bacteria that are constantly present in the mouth. The gum connects to the neck of the tooth with a band of fibers, which insert just above the bone into the root. In a healthy situation, the gum edge is higher than the fiber attachment, forming a space around the tooth. This is similar to having a turtleneck sweater, and this sulcus should be 2-3 millimeters in depth.

Healthy tooth and gums

Healthy gums

Close up

Probe next to sulcus

Probing 3mm into healthy sulcus

Everyone has bacteria in their saliva continuously. These bacteria precipitate (collect) on all surfaces, forming colorless, sticky colonies called plaque. Unfortunately, this plaque also forms in the space underneath the edge of the gum. If the plaque is not removed (something that takes careful brushing and flossing), it will start to cause an infection in the gum. Plaque that remains on the tooth for a long period of time absorbs salts from the saliva, and becomes hard. This calculus, or tartar, cannot be removed by brushing and flossing, and must be dislodged by a dental professional.

The Stages of Periodontal Disease
The first stage of periodontal disease is gum inflammation, or gingivitis (from "gingiva", meaning gum, and "itis", meaning inflammation). The body reacts to the bacteria by bringing in blood vessels, which carry cells to destroy the bacteria. This makes the tissue appear red, perhaps swollen, and patients may notice bleeding when cleaning their teeth.

Gingivitis starting

At this stage there has been no bone destruction, and careful removal of all calculus, along with meticulous patient brushing and flossing, generally completely corrects the problem.

If the gingivitis is not corrected, the bacteria may destroy the fiber barrier, and start moving down the tooth surface. There is a war between the advancing bacteria, and the body trying to defend against invasion. Some of the destruction is caused by the body itself, when attempts to destroy the bacteria also destroy healthy tissue in the area. There are many factors that influence how well your body defends against the bacterial invasion.

As the bacteria advances down the tooth, the inside lining of the gum, and the bone, are destroyed. This penetration of bacteria forms a periodontal pocket, or deepened space between the gum and tooth. By measuring the depth of the space with a periodontal probe your dentist can see how much bone loss has occurred.

Periodontal pocket with bone loss occurring

Periodontal probe measuring pocket

Probe held beside gum
to visualize depth of pocket

And when bone is lost, the tooth support is weakened. The tooth will become loose and, if the disease continues, will be lost.

Advanced Periodontitis

Gum Recession
In health, there are two types of gum tissues that surround the tooth. The part that is around the neck of the tooth is firmly attached to the tooth and underlying bone, and is called attached gingiva. The attached gingiva is immovable and tough, and deflects food as it hits the gum. Below the attached gingiva is looser gum, or alveolar mucosa. This tissue contains muscle, and is flexible to allow movement of the cheeks and lips. The muscles in the alveolar mucosa are constantly contracting, which pulls on the bottom edge of the attached gingiva. However, normally the attached gingiva is wide and strong enough to act as a barrier, which prevents the gum from being pulled down (receding).

Adequate attached (hard) gum to prevent
spontaneous recession. No grafting needed.

Some people are born without sufficient attached gingiva to prevent the muscle in the alveolar mucosa from pulling the gum down. In these cases the gum slowly continues to recede over time, even though the patient may be very conscientious with their oral health. This is not an infection, as is seen with periodontal disease, but rather simply an anatomic condition. Unfortunately, bone recession is occurring at the same time the gum is receding. This is because the bone, which is just under the gum, will not allow itself to become exposed to the oral cavity and moves down with the gum.

A lack of attached gingiva is sometimes associated with a high frenum attachment, which exaggerates the pull on the gum margin. A frenum is a naturally occurring muscle attachment, normally seen between the front teeth (either upper or lower). It is normal to have a frenum, but it should not pull on the gum margin or recession will occur. If pulling is seen, the frenum is surgically released from the gum with a frenectomy. Often a new band of hard gum is also added to re-establish an adequate amount of attached gingiva

With the wear and tear of time, even normal attached gum can be worn away, generally from vigorous brushing. This often happens in people with naturally thin tissues, or when the tissues have been stretched during orthodontics. If there is still adequate attached gum to act as a barrier to the muscle, the treatment for recession is to ensure further damage isn't done when brushing. However, if the attached gum is worn to the point where it cannot resist the constant pull of the mucosa, recession will continue unless a new hard band of gum is placed. Unchecked, the recession can cause tooth loss as the bone recedes with the tissue and tooth support weakens.