Gingiva
General description
Gingiva are part of the soft tissue lining of the mouth. They surround the teeth and provide a seal around them. Compared with the soft tissue linings of the lips and cheeks, most of the gingivae are tightly bound to the underlying bone which helps resist the friction of food passing over them. Thus when healthy, it presents an effective barrier to the barrage of periodontal insults to deeper tissue. Healthy gingiva are usually coral pink, but may contain melanin pigmentation.
Changes in color, particularly increased redness, together with edema and an increased tendency to bleed, suggest an inflammation that is possibly due to the accumulation of bacterial plaque. Overall, the clinical appearance of the tissue reflects the underlying histology, both in health and disease. When the gingival tissue is not healthy, it can provide a gateway for periodontal disease to advance into the deeper tissue of the periodontium, leading to a poorer prognosis for long-term retention of the teeth. Both the type of periodontal therapy and homecare instructions given to patients by dental professionals and restorative care are based on the clinical conditions of the tissue.
Macroscopic features of gingiva
The gingiva is divided anatomically into marginal, attached and interdental areas.
Marginal gingiva
The marginal gingiva is the terminal edge of gingiva surrounding the teeth in collar like fashion. In about half of individuals, it is demarcated from the adjacent, attached gingiva by a shallow linear depression, the free gingival groove. This slight depression on the outer surface of the gingiva does not correspond to the depth of the gingival sulcus but instead to the apical border of the junctional epithelium. This outer groove varies in depth according to the area of the oral cavity; the groove is very prominent on mandibular anteriors and premolars.
The marginal gingiva varies in width from 0.5 to 2.0 mm from the free gingival crest to the attached gingiva. The marginal gingiva follows the scalloped pattern established by the contour of the cementoenamel junction (CEJ) of the teeth. The marginal gingiva has amore translucent appearance than the attached gingiva, yet has a simi- lar clinical appearance, including pinkness, dullness, and firmness. In contrast, the marginal gingiva lacks the presence of stippling, and the tissue is mobile or free from the underlying tooth surface, as can be demonstrated with a periodontal probe. The marginal gingiva is stabilized by the gingival fibers that have no bony support. The gingival margin, or free gingival crest, at the most superficial part of the marginal gingiva, is also easily seen clinically, and its location should be recorded on a patient’s chart.
Attached gingiva
The attached gingiva is continuous with the marginal gingiva. It is firm, resilient, and tightly bound to the underlying periosteum of alveolar bone. The facial aspect of the attached gingiva extends to the relatively loose and movable alveolar mucosa, from which it is demarcated by the mucogingival junction. Attached gingiva may present with surface stippling. The tissue when dried is dull, firm, and immobile, with varying amounts of stippling. The width of the attached gingiva varies according to its location. However, certain levels of attached gingiva may be necessary for the stability of the underlying root of the tooth.
Interdental gingiva
The interdental gingiva occupies the gingival embrasure, which is the interproximal space beneath the area of tooth contact. The interdental papilla can be pyramidal or have a "col" shape. Attached gingiva is resistant to masticatory forces and always keratinised.
The col varies in depth and width, depending on the expanse of the contacting tooth surfaces. The epithelium covering the col consists of the marginal gingiva of the adjacent teeth, except that it is nonkeratinized. It is mainly present in the broad interdental gingiva of the posterior teeth, and generally is not present with those interproximal tissue associated with anterior teeth because the latter tissue is narrower. In the absence of contact between adjacent teeth, the attached gingiva extends uninterrupted from the facial to the lingual aspect. The col may be important in the formation of periodontal disease but is visible clinically only when teeth are extracted.
Interdental Areas
It is the part of gingiva which extends in between two teeth up to the contact point.There is a facial side interdental papilla and a lingual side interdental papilla.Interdental papilla has a summit(tip)and margins that are concave.The tip and the margins are unattached and the central portion attached.In inflammations the interdental papilla loses its concavity.
Characteristics of healthy gingiva
Color
Healthy gingiva usually has a color that has been described as "coral pink." Other colours like red, white, and blue can signify inflammation (gingivitis) or pathology. Although described as the colour coral pink, variation in colour is possible. This can be the result of factors such as: thickness and degree of keratinization of the epithelium, blood flow to the gingiva, natural pigmentation, disease and medications.
Since the colour of the gingiva can vary, uniformity of colour is more important than the underlying color itself. Excess deposits of melanin can cause dark spots or patches on the gums (melanin gingival hyperpigmentation), especially at the base of the interdental papillae. Gum depigmentation (aka gum bleaching) is a procedure used in cosmetic dentistry to remove these discolorations.
Contour
Healthy gingiva has a smooth arcuate or scalloped appearance around each tooth. Healthy gingiva fills and fits each interdental space, unlike the swollen gingiva papilla seen in gingivitis or the empty interdental embrasure seen in periodontal disease. Healthy gums hold tight to each tooth in that the gingival surface narrows to "knife-edge" thin at the free gingival margin. On the other hand, inflamed gums have a "puffy" or "rolled" margin.
Texture
Healthy gingiva has a firm texture that is resistant to movement, and the surface texture often exhibits surface stippling. Unhealthy gingiva, on the other hand, is often swollen and less firm. Healthy gingiva has an orange-peel like texture to it due to the stippling.
Reaction to disturbance
Healthy gums usually have no reaction to normal disturbance such as brushing or periodontal probing.
Unhealthy gums on the other hand will show bleeding on probing (BOP) and/or purulent exudate.
References
- Illustrated Dental Embryology, Histology, and Anatomy, Bath-Balogh and Fehrenbach, Elsevier, 2011, page 123
- Gingival Recession - Causes and treatment JADA, Vol 138. http://jada.ada.or. Oct 2007. American Dental Association
- Mexicodentaldirectory.com > dental sensitivity Retrieved on August 2010
- Mondofacto medical dictionary > gingival retraction 05 Mar 2000
- Mosby's Medical Dictionary, 8th edition. © 2009, Elsevier.
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