Dentistry

Dentistry is the medical activity focused on treating the teeth, the gums and the oral cavity. This includes treating teeth damaged due to accidents or disease, filling teeth damaged due to tooth decay, and replacing damaged or injured teeth with replacement teeth. Major disciplines of dentistry include orthodontics, which focuses on the correction of tooth problems such as gaps between the teeth, crowded teeth and irregular bite; and periodontics, which addresses gum problems. Dentistry is considered an independent medical art, with its own licensing procedure. Medical doctors are not licensed to treat teeth; likewise dentists are not licensed to treat other parts of the body.

Cavities and fillings

The great nineteenth century advances in dentistry provided dentists with the tools to repair or remove damaged teeth with a minimum of pain. The hallmarks of dentistry in the twentieth century have been advances in the preservation of teeth.

The success of these efforts can be seen in the fact that more older Americans retain their teeth. For example, the number of Americans without teeth was 18 million in 1986, according to the Centers for Disease Control. By 1989, the number had dropped to 16.5 million. Children also have fewer dental caries, the technical name for cavities. While nearly three quarters of all 9-year-olds had cavities in the early 1970s, only one-third of 9-year-olds had cavities in the late 1980s, according to the Centers for Disease Control.

But many dental problems and challenges still exist. The two most common types of oral disease are dental caries and periodontal disease, Rowe reports. Dental caries stem from the destruction of the tooth by microbial activity on the surface. Dental caries occur when bacteria forms a dental plaque on the surface of the tooth. Plaque is a deposit of bacteria and their products which is sticky and colorless. After the plaque is formed, food and the bacteria combine to create acids that slowly dissolve the substance of the tooth. The result is a hole in the tooth which must be filled or greater damage may occur, including eventual loss of the tooth.

Many different strategies exist to prevent dental caries. These include the reduction of sugar consumption. While some foods, such as starches, do not digest completely in the mouth, other foods, such as sugars, break down quickly in the mouth and are particularly harmful. Tooth brushing also helps reduce plaque. Other preventive techniques, such as the use of fluoride and sealants, are also helpful.

Fluoride was recognized as early as 1874 as a protector against tooth decay. Great controversy surrounded the addition of fluoride to the public water supply in many communities in the 1950s and 60s, as concerns were raised about the long-term health affects of fluoride. While controversy on the issue remains in some areas, public health experts suggest that fluoride has greatly improved dental health in young and old people. The number of cavities are reduced 65% in areas in which water is fluoridated.

Another advance was the development of sealants for children in the late 1960s. These sealants, made of a clear plastic material, are typically added to an etched tooth surface to protect the tooth from decay. They can protect teeth from cavities for up to 15 years. They are generally used on the chewing surfaces of back teeth, which are most prone to tooth decay. Sealants are currently recommended for all children by the American Dental Association.

Regular dental check-ups are used to monitor teeth and prevent dental caries from growing large. Contemporary dentists typically examine teeth using dental equipment to poke and probe teeth and x rays to see potential dental caries before they can be seen easily without aid. To detect problems, x-ray beams are focused on special photographic film placed in the mouth. The x rays create a record of the tooth, with the film documenting dental cavities or other problems in the tooth.

The process of fixing dental caries can be a short procedure depending on the size of the cavity. Small cavities may require no anesthesia and minimal drilling, while extensive dental caries may require novocaine or nitrous oxide to dull the pain and extensive drilling. Typically the process of filling a cavity begins with the dentist using a drill or a hand tool to grind down the part of the tooth surrounding the dental carry. The dentist then shapes the cavity, removes debris from the cavity, and dries it off. At this point a cement lining is added as to insulate the inside of the tooth. The cavity is filled by inserting an amalgam or some other substance in small increments, compressing the material soundly.

Teeth are usually filled with an amalgam including silver, copper, tin, mercury, indium, and palladium. Other materials may be used for front teeth where metallic fillings would stand out. These include plastic composite material, which can be made to match tooth color.

Controversy about the possible safety hazards of mercury in amalgam fillings led some Americans to have their amalgam fillings removed in the early 1990s. While mercury is a proven toxic chemical, there is no proof that mercury in amalgam fillings causes disease, according to the American Dental Association. Still, some experts suggest that dentists seek alternatives to mercury to combat potential problems and fear linked to mercury exposure.

Tooth replacement

Teeth that have large cavities, are badly discolored, or badly broken often are capped with a crown, which covers all or part of the crown, or visible portion, of the tooth. This can be made of gold or dental porcelain. Dental cement is used to keep the crown in place.

Bridges are created when individuals need some tooth replacement but not enough to warrant dentures, which offer more extensive tooth replacement. These devices clasp new teeth in place, keep decayed teeth strong, and support the teeth in a proper configuration. Missing or damaged teeth may lead to difficulty speaking and eating. Like bridges for rivers or streams, dental bridges can be constructed many different ways, depending on the need and the area that needs bridging. There are cantilever dental bridges and many other types. Some are removable by the dentist, and may be attached to the mouth by screw or soft cement. Others, called fixed bridges, are intended to be permanent.

Dentures, a set of replacement teeth, are used when all or a large part of the teeth must be replaced. New teeth can be made of acrylic resin or porcelain. Creating a base to set the teeth in is an ambitious undertaking, requiring the development of an impression from the existing teeth and jaws and the construction of a base designed to fit the mouth exactly and not add errors. Contemporary dentists generally use acrylic plastics as the base for dentures. Acrylic plastic is mixed as a dough, heated, molded, and set in shape.

Gum disease and bad breath

Gum disease is an immense problem among adults. The more common gum diseases, gingivitis, can be found in about 44% of all employed Americans 18–64. Periodontitis can be found in at least 14% of this group, though it and gingivitis is far more common among older people. Gingivitis is the inflammation of gum tissue, and is marked by bleeding, swollen gums. Periodontitis involves damage to the periodontal ligament, which connects each tooth to the bone. It also involves damage to the alveolar bone to which teeth are attached.

Untreated periodontal disease results in exposure of tooth root surfaces and pockets between the teeth and supporting tissue. This leaves teeth and roots more susceptible to decay and tooth loss.

Periodontitis and gingivitis are caused primarily by bacterial dental plaque. This plaque includes bacteria which produce destructive enzymes in the mouth. These enzymes can damage cells and connective tissue. To prevent gum disease from forming, experts suggest regular brushing, flossing and removal of bacterial plaque using various dental tools. Regular mechanical removal of plaque by a dentist or hygienist is also essential.

Periodontal surgery is necessary when damage is too great. During this procedure, gums are moved away from bone and teeth temporarily to allow dentists to clean out and regenerate the damaged area.

Another less serious dental problem is halitosis, or bad breath. Bad breath can be due to normal body processes or to illness. Halitosis early in the morning is normal, due to the added amount of bacteria in the mouth during sleep and the reduced secretion of saliva, which cleanses the mouth. Another normal cause of bad breath is when one is hungry. This occurs because the pancreatic juice enters the intestinal tract when one has not eaten for some time, causing a bad smell. Certain foods also cause bad breath, such as garlic, alcohol, and fatty meat, which causes halitosis because the fatty acids are excreted through the lungs.

Halitosis can also be caused by a wealth of illnesses, ranging from diabetes to kidney failure and chronic lung disease. Dental problems such as plaque and dental caries can also contribute to bad breath. Treatment for the condition typically involves treating the illness, if that is causing the problem, and improving oral hygiene. This means brushing the tongue as well as the teeth.

Orthodontics: the art of moving teeth

The practice of orthodontics depends on the fact that the position of teeth in the mouth can be shaped and changed gradually using pressure. Orthodontia is used to correct problems ranging from a bite that is out of alignment, to a protruding jaw, to crowded teeth. Typically orthodontia begins when individuals are in their early teens, and takes about two years. However, with the development of clear plastic braces, adults are increasingly likely to turn to orthodontia to improve their appearance, and make eating and talking more comfortable.

The process may require some teeth to be pulled. The removal of teeth allows for the growth of other teeth to fill the newly-vacant area. Braces are made up of a network of wires and bands made of stainless steel or clear plastic. The tubes are often anchored on the molars and the wires are adjusted to provide steady pressure on the surface of the teeth. This pressure slowly moves the tooth to a more desirable location in the mouth and enables new bone to build up where it is needed. Orthodontia can also be used to help move the jaw by anchoring wires to the opposing jaw.