Teeth are hard, bone-like structures in the upper and lower jaws in the mouth. They are covered by the enamel, which is the hardest part of the body. The main function of teeth is chewing food. Chewing is the first stop in the process of breakdown of food. Digestion begins as the teeth chop and grind food into smaller pieces. During chewing food is mixed with the saliva, a liquid produce 17217v2123r d in the mouth. The food then forms a moist pulp, which is easy to swallow.
A tooth consists of four parts: pulp, dentin, enamel, cementum
There is a connective tissue that surrounds and holds the root in the jaw socket. This tissue is called the periodontal ligament.
The pulp has two parts: the pulp chamber and the root canal. The pulp chamber lies in the crown of the tooth. The portion of a tooth that rises above the gum is the crown and the portion below is called the root. The root canal lies in the root of the tooth. Blood vessels and nerves enter the root cannel through a small hole at the tip of the root. They extend through the root canal and into the pulp chamber.
Dentin is harder than bone. It consists mainly of mineral salts and water but also has some living cells. It has fewer minerals but is still about 2\3rds hydroxyapatite. The protein is largely collagen and there is also 10%water. Dentin has a highly organized structure with an array of parallel pores extending from the center pulp cavity to the dentin enamel boundary.
Enamel lies over the dentin in the crown of the tooth. It enables the tooth to withstand the pressure placed on it during biting or chewing. Enamel consists of mineral salts and a small amount of water. Enamel is white but transparent.
The yellow color of the dentin shows through the enamel which is way most teeth appear slightly yellowish. As a person grows older small amounts of enamel begin to wear away.
This process is called attrition and occurs as a result of long term use of teeth .Enamel the outer layer of the exposed tooth has the highest concentration of minerals at ~90% and the proteins in it are not found somewhere else. The high mineral content (mature enamel has no cells and is no alive) makes it the hardest component and also most resistant to bacterial attack, since there is little organic matter present. A flaw, crevice or fissure in the enamel may be the starting point for dental caries.
As the surface wears away the tooth grows out of his socket exposing the root. These areas may then become more sensitive to hot and cold liquids. Cementum is hard as bone and consists mainly of minerals salts and water.
Cementum is more like bone in structure and its purpose is to act as the anchoragen of the periodontal ligament - a bunch of collagen fibres that hold the tooth in place and acts sock absorber between tooth and jaw bone (the ligament is what makes it possible to wiggle a healthy tooth).
It can be seen that teeth are hard and crunchy on the outside, soft on the inside. A tooth that was all enamel would be too brittle, likely to break on hard food. A tooth that was all dentin would be too soft and would wear away after a few years of chewing. Exactly the same structure is used in making a hammer: the front face is extremely hard, but the mass of the hammer head is much softer and tougher, so the hammer cannot shatter.
The glands are found in and around the mouth and throat. They all secret saliva into the mouth, the parodists through tubes that drain saliva, called salivary ducts, near the upper teeth , submandibular under the tongue and the sublingual through many ducts in the floor of the mouth. Beside these glands, there are many tiny glands called minor salivary glands located in the mouth and throat. Salivary glands produce the saliva used to moisten the mouth initiate digestion and help to protect teeth from decay. As a good health measure, it is important to drink many liquids daily. Dehydration is a risk factor for salivary glands diseases.
Salivary glands problems that cause clinical symptoms include:
Obstruction: Obstruction to the flow of saliva most commonly occurs in the parotid and submandibular glands, usually because stones have formed. Symptoms typically occur when eating. Saliva production stars to flow, but cannot exit the ducal system, leading to swelling of the involved gland and significant pain, sometimes with an infection .Unless stones totally obstruct saliva flow, the major glands will swell during eating and then gradually subside after eating, only to enlarge again only at the next meal. Infection can develop in the pool of blocked saliva, leading to more several pains and swelling in the glands. If untreated for a long time, the glands may become abscessed. It is possible for the duct system of the major salivary glands that connects the glands to the mouth to be abnormal. These ducts can develop small constriction, which decrease salivary flow, leading to infection and obstructive symptoms.
Infection The most common salivary gland inflection in children is mumps, which involves the parodist's glands while this is most common in children who have not been immunized, it can occur in adults. However if an adult has swelling in the area of parodists gland only on one side, it is more likely due to an obstruction or a tumor. Infection also occurs because of ducal obstruction or sluggish flow of saliva because the mouth has abundant bacteria.
A secondary infection of salivary glands from nearby lymph nodes may occur. These lymph nodes are the structures in the upper neck that often become tender during a common sore throat. In fact many of these nymph nodes are located on, within and deep in the substance of the parotid glands.
Tumors Primary benign and malignant salivary glands tumors usually show up as painless enlargements of these glands. Tumors rarely involve more than one gland and are detected as a growth in the parodit, submandibular area on the palate floor of mouth cheeks or lips. An ontolaryngogist-head and neck surgeon should check these enlargements.
Other disorders: Salivary glands enlargement also occurs in autoimmune diseases such as: HIV and Sjögren's syndrome where the body' s immune system attacks the salivary glands causing significant inflammation .Dry mouth and dry eyes are common. This may occur with other systemic diseases such as rheumatoid arthritis. Diabetes may cause enlargement of the salivary glands, especially the parodit glands. Alcoholics may have salivary glands swelling usually on both sides.
Treatment of salivary diseases falls into two categories: medical and surgical. Selection of treatment depends of the nature of problem. If it is due to systemic diseases then the underlying problem must be treated. This may require consulting with other specialists.If the disease process relates to salivary glands obstruction and subsequent infection, the doctor will recommend increase fluid intake and may prescribe antibiotics. Sometimes blocked ducts need to be opened.
If a mass has developed within the salivary glands, removal of the mass may be recommanded. Most masses in the parotid gland area are benign. When surgery is necessary great must be taken to avoid to avoid damage to the facial nerve within this gland that moves the muscles faces including the mouth and eye. When malignant masses are in the parodit glands, it may be possible to surgically remove them and preserve most of the facial nerve. Radiation treatment is often recommanded after surgery. This is administrated four to six weeks after the surgical procedure to allow adequate healing before irritation.
|
