A mucogingival junction is an anatomical feature found on the intraoral mucosa. The mucosa of the cheeks and floor of the mouth are freely moveable and fragile, whereas the mucosa around the teeth and on the palate are firm and keratinized. Where the two tissue types meet is known as a mucogingival junction.

There are three mucogingival junctions: on the facial

Commonly used terms of relationship and comparison in dentistry

There are numerous commonly used terms of relationship and comparison that refer to different aspects of teeth and are frequently utilized in articles about dentistry...

 of the maxilla

Maxilla

The maxilla is a fusion of two bones along the palatal fissure that form the upper jaw. This is similar to the mandible , which is also a fusion of two halves at the mental symphysis. Sometimes The maxilla (plural: maxillae) is a fusion of two bones along the palatal fissure that form the upper...

 and on both the facial and lingual

Commonly used terms of relationship and comparison in dentistry

There are numerous commonly used terms of relationship and comparison that refer to different aspects of teeth and are frequently utilized in articles about dentistry...

 of the mandible. The palatal

Commonly used terms of relationship and comparison in dentistry

There are numerous commonly used terms of relationship and comparison that refer to different aspects of teeth and are frequently utilized in articles about dentistry...

 gingiva of the maxilla is continuous with the tissue of the palate

Palate

The palate is the roof of the mouth in humans and other mammals. It separates the oral cavity from the nasal cavity. A similar structure is found in crocodilians, but, in most other tetrapods, the oral and nasal cavities are not truly separate. The palate is divided into two parts, the anterior...

, which is bound down to the palatal bones. Because the palate is devoid of freely moveable alveolar mucosa, there is no mucogingival junction.

Clinical importance

The clinical importance of the mucogingival junction is in measuring the width of attached gingiva

Gingiva

The gingiva , or gums, consists of the mucosal tissue that lies over the mandible and maxilla inside the mouth.-General description:...

. Attached gingiva is important because it is bound very tightly to the underlying alveolar bone and provides protection to the mucosa during functional use of the structures of the oral cavity during function, such as chewing

Mastication

Mastication or chewing is the process by which food is crushed and ground by teeth. It is the first step of digestion and it increases the surface area of foods to allow more efficient break down by enzymes. During the mastication process, the food is positioned between the teeth for grinding by...

. Without attached gingiva, the freely moveable alveolar mucosa, being more fragile, would suffer injury during eating and cleansing activities, such as brushing

Toothbrush

The toothbrush is an oral hygiene instrument used to clean the teeth and gums that consists of a head of tightly clustered bristles mounted on a handle, which facilitates the cleansing of hard-to-reach areas of the mouth. Toothpaste, which often contains fluoride, is commonly used in conjunction...

 of the teeth.

The width of attached tissue is critical, because the more there is available provides a greater sense of protection against the aforementioned insults to the tissue. Using the mucogingival junction as the boundary demarcating the apical

Commonly used terms of relationship and comparison in dentistry

There are numerous commonly used terms of relationship and comparison that refer to different aspects of teeth and are frequently utilized in articles about dentistry...

 border of the attached gingiva, a periodontal probe

Periodontal probe

A periodontal probe is an instrument in dentistry commonly used in the dental armamentarium. It is usually long, thin, and blunted at the end. The primary purpose of a periodontal probe is to measure pocket depths around a tooth in order to establish the state of health of the periodontium...

 in inserted into the gingival sulcus

Gingiva

The gingiva , or gums, consists of the mucosal tissue that lies over the mandible and maxilla inside the mouth.-General description:...

 to measure how much of the keratinized gingiva coronal

Commonly used terms of relationship and comparison in dentistry

There are numerous commonly used terms of relationship and comparison that refer to different aspects of teeth and are frequently utilized in articles about dentistry...

 to the mucogingival junction is in fact attached to the underlying bone. The depth of the gingival sulcus, determined by the depth to which the probe enters the sulcus, is not attached to the underlying bone, and is subtracted from the total height of the keratinized tissue.

Thus, if the entire height of the keratinized gingiva, from the free gingival margin

Free gingival margin

The free gingival margin is the interface between the sulcular epithelium and the epithelium of the oral cavity. This interface exists at the most coronal point of the gingiva, otherwise known as the crest of the marginal gingiva....

 to the mucogingival junction is 8 mm, and the probing depth on the tooth

Tooth

Teeth are small, calcified, whitish structures found in the jaws of many vertebrates that are used to break down food. Some animals, particularly carnivores, also use teeth for hunting or for defensive purposes. The roots of teeth are embedded in the Mandible bone or the Maxillary bone and are...

at that location is 2 mm, the effective width of attached gingiva is 6 mm.

If the probe enters the sulcus and can descend up to or beyond the mucogingival junction, that area is said to represent a mucogingival defect.