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 hard (attached) tissue to prevent spontaneous recession
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.
Insufficient attached gum
results in recession starting
Insufficient attached gum
without treament results in
continued loss of gum and bone
Lack of attached gum
with resulting recession
Note gum pulling away when cheek muscle retracted. The bone that previously covered the root has also receded.
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.
High frenum with lack of attached gum causing muscle pull and tooth separation
Child with naturally occurring high frenum attachment
After frenum removal, and addition of adequate 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.
Recession associated with a lack of attached gingiva. The bone has also receded. Untreated, this may result in tooth loss.
After placement of a gum graft, adequate attached gingiva to prevent further bone/tissue loss.
Recession with no attached gum. Without treatment, the recession will continue. The root is difficult to clean, leading to plaque formation and inflammation.
After placement of new attached gum.