DENTISTRY
Dentistry is a health profession
concerned with the prevention, diagnosis, and treatment of disorders of the
teeth and adjacent tissues of the head, neck, and mouth. A dentist is a person possessing
the education, experience, and legal qualifications required to practice
dentistry or any of its phases. The practice of dentistry includes cleaning,
filling, and extracting teeth, treating diseased gum tissues, correcting
irregularities in tooth alignment, performing surgical operations on the mouth
or jaw, and constructing and fitting artificial teeth or dentures.
Disorders in the mouth may cause
diseases of other parts of the body; conversely, the teeth and their supporting
structures are affected by abnormal conditions in distant parts of the body.
Because dental structures generally cannot repair themselves, care of the mouth
represents a unique health problem
for which dentistry uses its own procedures and techniques, as well as those of
medicine, in order to prevent local complications as well as ill effects
throughout the body.
Most dentists are general
practitioners in all phases of dentistry. Periodic examinations, including the
use of X-rays and special instruments and tests, are required in order to
detect disorders at an early stage. Encrustations of calculus (tartar), which
consists of mineralized bacterial plaque, products of bacterial metabolism,
salivary mucus, and food residue, should be removed from the teeth at least
once a year. Cavities in the teeth are filled with any of various appropriate
materials. Irregularities of alignment are corrected. Teeth badly broken down
may be rebuilt, or the dental pulp of infected teeth may require removal. Teeth
incapable of being restored must be extracted, and missing teeth need to be
replaced by artificial ones.
Dentistry can be subdivided into
eight specialized fields, although the general practitioner may undertake as
many of them as his or her interest and capabilities permit.
Oral Surgery
Oral surgery deals with the
diagnosis and surgical treatment of any disease, injury, malformation, or
deficiency of the jaws or associated structures. An important aspect of oral
surgery is the removal of teeth, which may be complicated by their location,
peculiar formation, or attachment to the jawbone. Teeth that are embedded in
the jawbone or soft tissue are said to be impacted. In such cases the
surrounding bone or tissue may have to be removed in order to reach the tooth.
Oral surgery also includes the removal of cysts and growths in the jaws and
mouth, the setting of fractures of the jaws, and operations for the correction
of cleft palate and harelip, both of which are forms of birth abnormalities.
Orthodontics
Orthodontics has as its function the
regulation of the position of the teeth in the dental arch. It deals with the
detection, study, prevention, and correction of the condition known as
malocclusion, which involves irregularities in tooth position and jaw
relationships, and which can lead to deformities of the jaws and face.
Malocclusion may be hereditary or may be an acquired defect caused by faulty
habits or early loss of teeth as a result of decay. By applying special devices
and appliances to the teeth, sometimes in combination with surgery, a proper
occlusion of the teeth can be effected by the orthodontist.
Prosthodontics
Prosthodontics deals with the various methods of
providing artificial substitutes, or dentures, for missing teeth, the
replacement of which ensures the even distribution of the forces involved in
chewing and thus prevents the loss of other teeth as a result of undue stress.
The nature of the restoration depends on the health of the remaining teeth and
supporting structures. If feasible, a fixed bridge is used to replace missing
teeth. This type of replacement is accomplished by constructing crowns, which
cover all or a large part of the adjacent teeth, and then by attaching the
artificial teeth to the crowns. A fixed bridge made of gold covered with
porcelain or acrylic (a plastic material) is lifelike and cannot be readily
removed. If sufficient adjacent teeth do not remain to support a fixed bridge,
then a removable partial denture is constructed. This type of prosthetic device
is usually secured by clasps, which embrace several of the remaining teeth. The
clasps may be made of gold or of a cobalt-steel alloy. This type of appliance
must be removed frequently to be cleaned. When all teeth must be replaced, a
full denture is made. The retention of this type of denture depends on the
firmness of the underlying tissues and the adhesion provided by the saliva in
the mouth. Full dentures are usually made of acrylic, reinforced occasionally
with metal. Prosthodontists also replace portions of
the oral cavity that are missing because of malformations or deficiencies.
Another surgical approach to tooth
replacement is the dental implant, which can take a number of forms. Screws may
be drilled into the jawbone to serve as anchors for caps, a metal blade may be
fixed to the bone and teeth can then be cemented to posts on the blade, or a
metal frame may be placed below the gum for tooth support when the bone itself
is too fragile. A full set of teeth may be implanted by such means. These
expensive processes are not favored by all dentists, but a growing number of
patients are choosing implant surgery.
Periodontics
Periodontics is concerned with the study and
treatment of the supporting structures and tissues surrounding the teeth. The
gums, or gingiva, and the underlying bone are subject
to many disorders. Calculus encrustations on the teeth, which form over and
under the gum, act as an irritant to the underlying tissues. Food accumulating
on the neck of the tooth and irregularities such as cavities, malocclusions, or
poorly constructed dental appliances also act as irritants. In addition,
imbalance of tooth-cusp relationships may force food particles into the gums.
When subjected to irritants, such soft tissues as the gingiva
become inflamed, and eventually the adjacent bone may be destroyed. Thus, the
tooth ultimately becomes loosened because of the loss of bone around its roots.
Inflammation of the gum is called
gingivitis, and infections destroying the gum tissue and bone are called periodontitis. Although gum diseases are the greatest
single cause of tooth loss after the age of 21, these conditions also occur in
children. Another common gum disorder is necrotizing ulcerative gingivitis,
known commonly as trench mouth, or Vincent's infection. When untreated, it
destroys the interdental papillae (small
protuberances) of the teeth and causes loosening of the teeth; it is often
associated with widespread infection. Other common diseases of the mouth
include thrush and viral infections.
Periodontal treatment includes the removal
of calculus with curettes (tools for scraping) and scalers,
and the application of medicines to the soft tissues. Loosened teeth may be
splinted together for support during the healing process; infected or
necrotized gum tissue is excised; and malocclusions are corrected by grinding
the teeth to obtain effective occlusal relationships.
Endodontics
Endodontics deals with
surgical and therapeutic procedures involved in the protection of the pulp
(commonly known as the nerve) or its removal from the pulp cavity when diseased
or injured, and root canals. Bleaching of front teeth is also included in this speciality.
Pediatric Dentistry
The field of pediatric dentistry
(formerly called pedodontics) deals with the general
practice of dentistry for patients under 20 years of age and, in general,
patients possessing wholly deciduous or mixed dentition—that is, both primary
and permanent teeth. The practice may include the use of such appliances as
space maintainers and bite plates for the prevention or treatment of
malocclusion. Another pediatric procedure sometimes practiced is to apply a
sealant to protect the chewing surfaces of a child's molars from bacteria. The
teeth are first treated with a solution to make them more porous to the plastic
resin that is then applied, making them more resistant to decay.
Oral Pathology
Oral Pathology is concerned with the
nature of oral disease, its causes, processes, and effects, together with the
alterations of function and structure. Diagnosis of oral disease is accomplished
through the use of laboratory tests of sputum, blood, and other body fluids, as
well as through the microscopic examination of tissues. The oral pathologist,
who usually works in the laboratory of a hospital, serves the patient only
indirectly through consultation with the general practitioner.
Public-Health Dentistry
Public-health dentistry is concerned
with the prevention and control of dental diseases and the promotion of dental
health through organized community efforts. It relates to three basic career
areas in dentistry: dental public health, research, and clinical dentistry.
Each of these career areas may involve practice, teaching, or administration.
