Periodontal Anatomy – Gingiva
The gingiva (gums) are found in the oral cavity of humans surrounding part of their teeth. They are comprised of mucosal tissue which covers the alveolar processes of the mandible and maxilla and finish at each tooth’s neck.
Gingiva Characteristics
The gums make up a part of the soft tissue lining the mouth. They surround and provide seals around the teeth. Most of the gums are bound tightly to the underlying bone unlike the soft tissues lining the cheeks and lips. If the gingiva are healthy, they provide an effective barrier that protects deeper tissue from periodontal insults. The texture of healthy gums is firm and often shows surface stippling (similar to an orange peel).
Healthy gums in lighter skinned people are typically pinkish but can be naturally darker with melanin pigmentation. Since color variations in gums are natural, color is not as important as uniformity of color. The clinical appearance of the gum tissue reflects the underlying disease and health histology. Gum redness or color changes, swelling, and bleeding could all indicate inflammation (gingivitis) due to bacterial plaque accumulation. When gum tissue is not optimally healthy, is makes a patient susceptible to periodontal disease advancing into the deep tissue of the periodontium thereby reducing the likelihood of long-term teeth retention.
Healthy gums should have a scalloped appearance, contour around each tooth, and fill the spaces between the teeth. When gums are healthy, each tooth is firmly held in place while maintaining a razor thin free gingival margin. Inflammation, such as that from gingivitis or periodontal disease, can cause the gums to look “puffy” or have a “rolled” margin.
Types of Gingiva
The three types of anatomically defined gingiva are known as the attached gingiva, the marginal gingiva (mobile), and interdental areas
Attached Gingiva: Gingival tissue laying between the alveolar gingiva and the mobile gingiva. The tissue is roughly four to five millimeters wide, depending on location, and tightly affixed to the underlying periosteum of alveolar bone. Stippling is present to varying degrees and when dry, the tissue is immobile, firm, and dull.
Marginal Gingiva: A strip of gingival tissue surrounding the neck of each tooth. For roughly half of individuals, the marginal gum is demarcated from the adjacent, attached gums by a shallow linear depression known as the free gingival groove. Depth of the outer groove varies based on the oral cavity area and is very prominent on mandibular anteriors and premolars.
When measured from the free gingival crest to the attached gingiva, width of the marginal gum ranges from 0.5 to 2.0 mm. While the clinical appearance, such as dullness, firmness, and pinkness, of the marginal gingiva are similar to those of the attached gingiva, it has a more translucent appearance. Stippling is not present and because the soft tissue is moveable, a probe can be inserted up to three millimeters into the sulcus formed between the mucosa and the tooth when performed in a healthy mouth.
Interdental Areas: Area of gum laying between the teeth, the interdental gums occupy the interproximal space beneath the area of tooth contact known as the gingival embrasure. They are covered in keratin and resistant to the force of chewing.