Beyond Teeth: A Map of Your Mouth
There’s more to a mouth than teeth. Several other important oral structures enable the teeth to do their job.
Oral mucosa. This is the soft pinkish-to-purplish tissue covering the inside of the mouth. Its primary function is to prevent irritants and infectious agents from entering the body. A fibrous protein called keratin makes most of the surfaces of the oral mucosa more resistant to injury.
Gums. Gum tissue (gingiva), a specialized portion of the oral mucosa, connects to each tooth at the neck and extends over the root and supporting bone. In a healthy mouth, the root remains entirely out of sight below the gum line. The gum tissue attaches securely to the underlying structures except at the upper edge, where it forms a tiny flap about 1.5 millimeters wide, at the margin of the tooth and gum. The V-shaped hollow under this flap is called the sulcus. It’s easy for food and bacteria to get trapped in this pocket. This can lead to inflammation and eventually to periodontal disease, also called gum disease. Because gum tissue contains no keratin, it’s particularly vulnerable to infection from bacteria that collect in the sulcus.
Bones and jaw. The five bones that make up the mouth include the powerful, horseshoe-shaped lower jaw (the mandible); the two bones of the upper jaw (the maxilla); and the two bones that form the roof of the mouth (the palate). The roots of the teeth fit into individual depressions, or sockets, in the bony ridge called the alveolar bone that lines each jaw. The way in which your upper and lower teeth come together when you close your mouth is called your bite, or occlusion. For you to chew effectively, your teeth must mesh correctly.
Tongue. This muscular structure manipulates food in your mouth, bringing it into contact with the teeth and moving it into the throat. Your tongue is also essential for clear speech. Taste buds on the tongue enhance the pleasure of eating.
Salivary glands. Three pairs of glands release saliva into the mouth. There are two types of saliva: a watery substance that clears food and dead cells from the lining of the mouth, and a thicker secretion that binds chewed food into a ball so it can be swallowed.
Saliva serves many purposes. It helps cleanse food and bacteria from the teeth, protects the mucosa from irritants and toxins that enter the mouth, and prevents the membranes from drying out. Saliva forms a protective film on the teeth, and its slightly alkaline pH helps neutralize acids (from food, drink, bacteria, or the digestive process) that could erode tooth enamel. It also contains compounds that destroy or prevent the growth of certain microbes, especially fungi.
In addition, saliva contains calcium and phosphorous, which help regenerate tooth enamel that’s been damaged by decay. Adding fluoride to the saliva, by way of toothpaste, drinking water, or mouth rinses, amplifies these healing effects. An insufficient flow of saliva—which can be caused by medications, radiation, or certain diseases—greatly increases your risk for tooth decay.
Source: Dental Health for Adults: A Guide to Protecting Your Teeth and Gums. Copyright © by Harvard University. All rights reserved.