dentistry

/den"teuh stree/, n.

the profession or science dealing with the prevention and treatment of diseases and malformations of the teeth, gums, and oral cavity, and the removal, correction, and replacement of decayed, damaged, or lost parts, including such operations as the filling and crowning of teeth, the straightening of teeth, and the construction of artificial dentures.

[1830-40; DENTIST + -RY]

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Profession concerned with the teeth and mouth.

It includes repair or removal of decayed teeth, straightening and adjustment of teeth for proper occlusion, and design, manufacture, and fitting of false teeth and other prosthetic devices. X rays are used to show conditions not visible on examination. Using local anesthesia, caries in teeth are drilled to remove diseased areas and filled with various materials. Decay that reaches a tooth's root risks infection of the nerve and requires root-canal surgery. Teeth that must be extracted are replaced by crowns for single teeth and full or partial dentures for more. Dentists also educate patients on oral hygiene, examine and clean teeth, and apply fluoride compounds for decay resistance.

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Introduction

 the profession concerned with the prevention and treatment of oral disease, including diseases of the teeth (tooth) and supporting structures and diseases of the soft tissues of the mouth. Dentistry also encompasses the treatment and correction of malformation of the jaws (jaw), misalignment of the teeth, and birth anomalies of the oral cavity such as cleft palate. In addition to general practice, dentistry includes many specialties and subspecialties, including orthodontics and dental orthopedics, pediatric dentistry, periodontics, prosthodontics, oral and maxillofacial surgery, oral and maxillofacial pathology, endodontics, public health dentistry, and oral and maxillofacial radiology.

History of dentistry

Early dentistry

      Dentistry, in some form, has been practiced since ancient times. For example, Egyptian (Egypt, ancient) skulls dating from 2900 to 2750 BCE contain evidence of small holes in the jaw in the vicinity of a tooth's roots. Such holes are believed to have been drilled to drain abscesses (abscess). In addition, accounts of dental treatment appear in Egyptian scrolls dating from 1500 BCE. It is believed that the Egyptians practiced oral surgery perhaps as early as 2500 BCE, although evidence for this is minimal. An early attempt at tooth replacement dates to Phoenicia (modern Lebanon) around 600 BCE, where missing teeth were replaced with animal teeth and were bound into place with cord.

      True restorative dentistry began with the Etruscans (Etruscan), who lived in the area of what is today central and northern Italy. Numerous dental bridges and partial dentures (denture) of gold have been found in Etruscan tombs, which date to about 500 BCE. The Romans, who conquered the Etruscans, adopted Etruscan culture, and dentistry became a regular part of Roman medical practice. The Greeks also practiced some form of oral medicine, including tooth extractions, from the time of Hippocrates, around 400 BCE.

      In the Eastern world, dentistry had a totally different history. There is evidence that the early Chinese practiced some restorative dentistry as early as the year 200 BCE, using silver amalgam as fillings (filling). Oral medicine was part of the regular medical practice in other early Asian civilizations, such as those in India and Japan.

      Because of the proscription in the Qurʾan (Qurʾān), the sacred scripture of Islam (Islām), against mutilating the body, surgery was not practiced in Islamic countries. Instead, reliance was placed upon healing through the use of herbs (spice and herb) and medicines; preventive dentistry through strict adherence to oral hygiene became paramount. The writings of early Arabic physicians, such as Avicenna and Abū al-Qāsim, show that scaling and cleaning of teeth were practiced. Extractions were rare and were performed only when a tooth had been loosened.

Development of dentistry in Europe

      With the demise of the western Roman Empire about the year 475 CE, medicine in Europe declined into a torpor that would last for almost a thousand years. About the only places where medicine (medicine, history of) or surgery was practiced were monasteries (monastery), and monks (monk) were aided in their surgical ministrations by the local barbers (barber), who went to the monasteries to cut the monks' hair and shave the monks' beards. In 1163 a church council at Tours, France, ordered that henceforth no monks or priests were to practice any surgery, since it was felt that the shedding of blood was incompatible with the holy office of the clergy. Thus, the only people who had any rudimentary knowledge of surgery were the barbers, and they stepped into the breach, calling themselves barber-surgeons. They practiced simple dentistry, including extractions and cleaning of teeth. In the 1600s a number of barber-surgeons began restricting their activity to surgery and dropped the word “barber,” simply calling themselves surgeons. In England, Henry VIII granted a charter to a combined group of barbers and surgeons, which ultimately evolved into the Royal College of Surgeons.

      In 1530 the first book devoted entirely to dentistry was published in Germany and was written in German instead of Latin. It addressed barber-surgeons and surgeons, who treated the mouth, rather than university-trained physicians, who ignored all diseases of the teeth. Subsequent to this publication, other surgeons published texts incorporating aspects of dental treatment.

      By the 1700s in France, a number of surgeons were restricting their practice to dentistry, and in 1728 a leading Parisian surgeon, Pierre Fauchard, gathered together all that was then known about dentistry in a monumental book, The Surgeon Dentist, or Treatise on the Teeth. In it he discussed and described all facets of diagnosis and treatment of dental diseases, including orthodontics, prosthetics, periodontal diseases, and oral surgery. Fauchard effectively separated dentistry from the larger field of surgery and thus established dentistry as its own profession. Fauchard is known today as the father of modern dentistry. Other surgeons in Germany and France, who made notable contributions to the field of dentistry, readily followed his lead.

      English dentistry did not advance as far as French dentistry in the 18th century. The guild that had united the barbers and surgeons was dissolved in 1745, with the surgeons going their own way. Some barbers continued their dental ministrations and were designated “tooth drawers.” A second group, as a result of the French influence, referred to themselves as “dentists,” while those who did all manner of dentistry were called “operators for the teeth.” The first English book on dentistry, The Operator for the Teeth, by Englishman Charles Allen, was published in 1685; however, no other works on English dentistry were published until Thomas Berdmore, dentist to King George III (George III), published his treatise on dental disorders and deformities, in 1768. In 1771 English surgeon John Hunter (Hunter, John), famed as the father of modern surgery, published The Natural History of the Human Teeth, an outstanding text on dental anatomy. Hunter also pioneered the transplantation (transplant) of teeth from one individual to another, and, because of his tremendous reputation, this practice was widely adopted. Although tooth transplantation between individuals did not prove successful, it was nevertheless the first attempt to transplant human tissue from one person to another. In 1806 English dentist Joseph Fox, who served on the staff of Guy's Hospital in London, offered the first observations on what is today recognized as the “rejection phenomenon” of transplants.

Dentistry in 18th- and 19th-century America

      The beginnings of dentistry in the United States came in the 1630s with the settlers of the Massachusetts Bay Colony, who were accompanied by barber-surgeons. One of the first dentists in America was English surgeon and dentist John Baker, who settled in Boston in 1763. Other immigrants to follow included Robert Wooffendale, who emigrated from England in 1766 and practiced in New York City, and Jacques Gardette, who moved from France in 1778, eventually settling in Philadelphia. In early colonial America, dental care was also rendered by artisans such as ivory turners. One such artisan was Isaac Greenwood, who began practicing dentistry in 1779 and is considered to be the first American-born dentist. Four of his six sons became dentists. The most prominent, John Greenwood, served as George Washington (Washington, George)'s dentist. Other craftsmen performed a variety of dental services, the most well known being Paul Revere (Revere, Paul), who practiced dentistry for seven years in Boston. The first book on dentistry to be published in the United States appeared in 1801 and was written by Richard Cortland Skinner, a young immigrant from England.

      By the first quarter of the 19th century, the United States had become the leading centre in the world for dental developments. From 1839 to 1840 three major events in dental practice facilitated the establishment of dentistry as a true profession. In 1839 the first dental journal, the American Journal of Dental Science, was launched; in 1840 the first dental school, the Baltimore College of Dental Surgery, was established; and in 1840 the first national society of dentists, the American Society of Dental Surgeons, was founded in New York City.

 Great new advances in the field came about very quickly at this time. In 1844 American dentist Horace Wells (Wells, Horace) discovered the anesthetic properties of nitrous oxide, which he promptly began using while performing tooth extractions. In 1846 another American dentist, William Thomas Green Morton (Morton, William Thomas Green) of Boston, successfully demonstrated in public the effectiveness of ether anesthesia. Because Wells's own public demonstration prior to Morton's was unsuccessful, a controversy erupted over who deserved credit for the remarkable discovery of anesthesia. However, the two major health organizations in the United States—the American Dental Association and the American Medical Association—voted in favour of Horace Wells in 1864 and 1870, respectively.

      Numerous advances in equipment, materials, and techniques followed one upon the other. In 1864 vulcanized rubber was introduced as a substitute for difficult and costly gold dentures (denture), allowing dentists to supply dentures at a lower cost. The introduction of a foot-treadle drill in 1871 by American dentist James Beall Morrison of Missouri supplanted awkward handheld drills and gave dentists the ability to create intricate and aesthetic restorations.

      New dental schools were being established in many parts of the nation. The first dental school to be affiliated with a university was that at Harvard University in 1867. Nevertheless, most dentists were still being trained by a system of preceptorship with an established dentist. The beginning of licensure in the United States came about in 1868, with the states of New York, Ohio, and Kentucky leading the way.

      In 1890 American dentist Willoughby Dayton Miller published The Micro-organisms of the Human Mouth, in which he proposed the theory that dental caries (caries) were the result of bacterial activity. Miller's publication led to a tremendous wave of interest in oral hygiene. In 1913 American dentist Alfred C. Fones opened the Fones Clinic for Dental Hygienists in Bridgeport, Conn., the first establishment for formal training, at the college level, of dental hygienists.

Dentistry in 19th-century Europe

 In the 19th century in Europe, several technological developments were taking place. Chief among these developments was the introduction of porcelain teeth for dentures by Italian dentist Guiseppangelo Fonzi. Fonzi's porcelain teeth provided an appealing alternative to traditional tooth replacement with the repugnant teeth from corpses.

      In Britain, dentistry was also coming of age. In 1856 English dentist Sir John Tomes led the formation of the first dental organization in England, the Odontological Society. It was through the activity of this group that the Royal Dental Hospital of London was established in 1858. In opposition to the Odontological Society, a group of dental professionals formed the College of Dentists of England in 1857, seeking independence from the Royal College of Surgeons, which influenced the proceedings of the Odontological Society. The College of Dentists of England established the Metropolitan School of Dental Science, the forerunner of the University College Hospital Dental School. In 1878 the passage of the Dentists Act, which put dentistry under the General Medical Council, led to the authorization and formation of the Dental Register, a precursor to ultimate licensure that prescribed a curriculum for the training of dentists. This system remained in effect until 1921, when new laws provided for stricter requirements for examination and licensure. In 1880 the British Dental Association was established; it remains the most important dental organization in the United Kingdom.

Advances in dentistry in the 20th century

      In 20th-century America, advances occurred in all aspects of dentistry. Frederick McKay, a young American dentist practicing in Colorado, observed a condition of mottling of his patients' teeth, in which there was an almost total absence of decay. Following years of research, McKay and others were able to show that this was due to the presence in the drinking water of high amounts of naturally occurring fluoride, which protects teeth against decay. As a result, public health officials established measures to add fluoride to public water supplies in communities around the United States. Since fluoridation was initiated in 1945, dental caries in children have decreased by more than 50 percent.

      In 1896 American dentist Charles Edmund Kells introduced X-ray technology in dentistry and thereby ushered in an era of accurate diagnosis of dental ailments. In addition, in the late 19th and early 20th centuries, American dental pathologist Greene Vardiman Black (sometimes called the father of modern dentistry, although this title is shared with Fauchard) standardized the instruments and restorative materials used by dentists. In 1903 American dentist Charles Land introduced the use of porcelain in crowns, which led to a new era of aesthetic dentistry. In 1907 American dentist William Taggart introduced a precision casting machine that allowed dentists to create gold restorations of great accuracy with a minimum of tooth removal. In 1913 American dentist Edwin J. Greenfield demonstrated the first modern and truly functional dental implant, paving the way for today's highly successful implant dentistry. The introduction in 1953 of the first commercially successful water-driven turbine drill, developed by American dentist Robert Nelson, led the way to the high-speed dental drill. The Borden air-turbine drill, introduced in 1957 and today used universally, reaches speeds of up to 400,000 revolutions per minute and allows for greater accuracy and control by the dentist and greater comfort of the patient.

      Numerous research projects into dental diseases and their treatment are carried out at the U.S. National Institute of Dental and Craniofacial Research in Bethesda, Md., a component of the National Institutes of Health. The work done at such institutes promises a future in which new materials and new methods of treatment greatly diminish oral and dental disease.

Malvin E. Ring

The practice of dentistry

Licensure requirements

      The practice of dentistry is well controlled, and, in all countries of the world in which dentistry is practiced, there is a licensing requirement. The licensing authority may be the government or national dental organizations.

Canada

      In Canada each province has its own licensing authority. This can be a college, such as the Royal College of Dental Surgeons of Ontario, or an association, such as the Manitoba Dental Association. There is also a national authority, the Dental Examining Board.

      The university degree (Doctor of Dental Surgery or Doctor of Dental Medicine) does not in itself entitle the holder to practice but is an academic qualification for presentation to the licensing board under whose jurisdiction the holder wants to obtain a license to practice. The regulations of the provincial licensing boards vary but usually require an examination for licensing.

United States

      Licensing authority in the United States is vested in state boards of dental examiners, most of which require an examination. Most states require U.S. citizenship as a prerequisite. Some states require noncitizens to submit the declaration of intent to become a citizen or the first papers as a requirement for admission to the dental licensure examination; a few do not require citizenship for such admission.

      Nationals with foreign diplomas may be admitted to practice if their diplomas were issued by a school approved by the American Dental Association and if they pass the state licensure examination. Most states, however, require that dentists from foreign countries (generally with the exception of Canada) attend an accredited dental school in the United States for at least two years.

Europe

      The European Union (EU) has established policies that allow physicians and dentists to move freely and practice within any of the member countries. For this to be acceptable there has had to be mutual recognition of dental degrees and comparable forms of qualification. The EU has directives that set out the training requirements for dental education in the member states. This has created no difficulties for most European countries, where dentistry has long been recognized as a specialty in its own right. The Council of European Dentists oversees the development and execution of policies and initiatives that influence dental practice in Europe.

      Permission to practice in the United Kingdom is granted by the General Dental Council (GDC) to those holding (1) a degree or diploma in dentistry or dental surgery conferred in Great Britain or Northern Ireland, (2) a degree or diploma in dentistry or dental surgery granted elsewhere that has been recognized by the GDC, or (3) a degree or diploma approved by the GDC, provided that these graduates have passed the statutory examination written under arrangements made by the GDC.

      Dentists in Germany must hold a dental surgeon's diploma, which authorizes private practice without further examination. They must be registered by local dental boards and by health authorities.

      In Italy a diploma in dentistry, which allows the use of the title of specialist in diseases of the mouth, teeth, and jaws, constitutes a license to practice. Holders of the diploma of Doctor of Medicine have passed examinations in dentistry and for this reason may also practice dentistry but do not have the specialist title.

Japan

      Since about 1903 Japanese dentistry has been mainly patterned after that practiced throughout the United States. Those wanting to practice dentistry or dental surgery must be recognized by the national government. Applicants for registration must pass the national examination for dentists and obtain a license to practice. These requirements must also be fulfilled by registered medical practitioners wanting to practice dentistry, by Japanese citizens, and by foreigners who have qualified in Japan.

Types of practice

Private practice

      In Canada, the United States, the United Kingdom, and Australia, dentists in private practice constitute the vast majority of all licensed dentists. The situation is much the same in France and various other countries.

      Dental practice has changed significantly since the 1920s, without a concurrent change in the basic dental curriculum. Dental procedures have shifted from the repair and extraction of teeth for the relief of pain to the prevention of disease. Dental practice has also changed in larger urban centres from the isolated private practice common in the early decades of the 20th century to a complex system of groups of professionals in a central location. Extensive use is made of dental hygienists, who often receive the patient from the examining dentist. Dental hygienists provide services such as performing preventive procedures, scaling, taking X-rays (X-ray), and teaching dental health strategies. Most practices also use dental assistants.

      Another development that has occurred in dental health care services is the extension of the duties currently carried out by dental auxiliaries (dental auxiliary). New Zealand has pioneered in the field with the creation of the dental nurse, an auxiliary who is trained to provide dental care for children without the supervision of a dentist. The United Kingdom has also developed the dental auxiliary, who performs somewhat similar duties but under closer supervision. In Canada and the United States, pilot projects have been conducted to test the feasibility of using dental auxiliaries for certain operative procedures in order to increase productivity, quality, and general service to the public.

       France may be taken as an example of the development of the practice of dentistry in continental Europe. There are two types of dentists practicing in France, the chirurgien dentiste (“dental surgeon”) and the stomatologist. The practice of dentistry in France by a chirurgien dentiste has since 1892 been restricted to persons of French nationality who hold a state diploma and who are registered with the Order of Dentists. The Order of Dentists is responsible for registration and discipline but is not concerned with dental education, which is controlled by the state through the common state diploma.

      Stomatologists are practitioners who have a diploma in medicine and either a diploma in dental surgery or a certificate of special studies (two years) in stomatology (see below Other disciplines (dentistry)). Specialization within the field of dentistry is not encouraged. There are no rules laid down for it, nor are there any special courses or diplomas or titles.

hospital dental practice

      Three types of dental care are normally carried out in the hospital environment: (1) clinical procedures normally provided in a dental office, for ambulatory inpatients and outpatients, (2) bedside care for persons admitted for other medical reasons, and (3) inpatient care for patients admitted to a hospital for purely dental conditions.

      Dentists may treat patients in hospitals either privately, on a fee-for-service basis, or under some form of government program, such as the National Health Service in the United Kingdom or the Provincial Medicare Plan (surgery only) in Canada. Hospital dental services have for years been an integral part of dental health care and dental education in the United Kingdom, and such services by hospital dental departments have expanded steadily in the United States and Canada.

      Hospital dental departments are normally established in the same manner as any other hospital department and are headed by a chief of service, who has the same status as other chiefs of service within the hospital. In some instances the chief of the dental department may be responsible to the chief of surgery. There are two types of hospital dental departments—one that is established in a teaching hospital and the other that is in a general hospital with no teaching component. In the teaching hospital the dental department is associated with a faculty of dentistry and forms an integral part of the undergraduate curriculum and, if they exist, of the graduate and postgraduate programs. One of the chief purposes of hospital dental departments is to make available the service of consultants to other hospital departments and general practitioners. This service is most highly developed in teaching hospitals. Usually, certain general dental treatment is provided for inpatients and outpatients. Hospital dental services or departments are prevalent in western Europe.

Public health practice

      Generally typical of dental public health practice in Canada and in many areas of the United States is the program in Ontario. There, dentists trained in public health, hygienists, and dental assistants carry out a preventive and educational program basically concerned with the examination of children, the recording of basic dental conditions, and the provision of dental health education.

Military practice

      Most countries of the world provide dental care for their armed services. In Canada the Canadian Forces Dental Service, with a brigadier general as director, has the same status as the Canadian Forces Health Service. In the United States, each branch of the military has its own dental corps, each on a par with the various medical corps. There are an Army (United States Army, The) Dental Corps, a Navy (United States Navy, The) Dental Corps (which serves personnel of the Marine Corps (United States Marine Corps, The) as well as the Navy), an Air Force (United States Air Force, The) Dental Corps, and a Coast Guard (United States Coast Guard) Dental Corps. Each of these corps is headed by an officer of the rank of brigadier general or rear admiral. In wartime the Public Health Service provides dental service to personnel of the merchant marine.

Governmental practice

      In many countries dentists are required to work a number of years for the government before they may be considered private practitioners of the type known in Canada and the United States. This service requirement may be based on the fulfillment of an obligation for government financial support during undergraduate training, or there may be a government regulation that all dental graduates must work for the state for a prescribed number of years. Another example of government practice is in the United Kingdom, where dentists are employed by local authorities to provide dental care under the Maternal and Child Welfare Services and the School Dental Service.

      The employment of dentists on a salary basis for the general practice of dentistry is not extensive in the United States or Canada. At the national level it may be the provision of dental care for eligible Native Americans (Native American) and Eskimos (Eskimo), war veterans, or inmates of penitentiaries. At a municipal level dentists may be employed in a school dental service. Dentists in both Canada and the United States commonly agree to provide service for families who qualify for social assistance. They are paid on a fee-for-service basis; the fee schedule is usually set, normally after consultation with the dentist, by the agency responsible for the social service plan.

      Government medical care was introduced in Japan in the late 1930s. This system was expanded until by 1962 almost the entire population was covered. There are limitations to the services offered by government medical care, as in orthodontics or in preventive dentistry.

Dental specialties and subspecialties

      In most countries that recognize specialties in dentistry, the specialist is limited to practice in the specialty and cannot carry out the practice of general dentistry. Where the specialty is thus limited, the general dentist may refer patients, and a specialist's practice is mainly on a referral basis. In Britain and in certain provinces in Canada, specialists may conduct a general practice. In the United States nine specialties are recognized by the American Dental Association: orthodontics and dentofacial orthopedics; pediatric dentistry; periodontics; prosthodontics; oral and maxillofacial surgery; oral and maxillofacial pathology; endodontics; public health dentistry; and oral and maxillofacial radiology.

orthodontics and dentofacial orthopedics

       orthodontics takes as its aims the prevention and correction of malocclusion of the teeth (tooth) and associated dentofacial incongruities. Orthodontics has been practiced since ancient times, but methods of treatment involving the use of bands and removable appliances have been prominent only since the beginning of the 20th century. The United States gave impetus to the development of orthodontics, which was recognized as a specialty with the formation of the American Society of Orthodontists in 1900.

      The demand for this service extends from the child to the mature adult, although human bone responds to tooth movement best in a person under 18, and it is generally agreed that children benefit more from treatment than do adults. In general, oral health and physical appearance are the two most important reasons for undertaking a course of orthodontic care.

Pediatric dentistry (pedodontics)

 Pediatric dentistry, analogous to pediatrics in medicine, is concerned with the dental care of children and adolescents.

      Much of the routine of practice is centred on the control of caries (tooth decay) and involves the use of fluoride and dietary and hygienic instruction. The need to influence tooth positions presents the next most frequently encountered problem. The correction of incipient abnormalities in tooth alignment may obviate the necessity for lengthy treatment. Many pediatric dentists use growth-influencing techniques to correct jaw alignments. Patience and a working knowledge of children's behaviour patterns and childhood physical and mental diseases and disease ramifications are important qualifications of the pedodontist.

periodontics

       periodontics is concerned with the prevention, diagnosis, and treatment of diseases of the periodontal (periodontal membrane) tissues—the tissues that surround and support the teeth. These tissues consist mainly of the gums (gum) and the jaws and their related contiguous structures.

      The most prevalent periodontal disease is periodontitis, commonly called pyorrhea, an inflammatory condition usually produced by local irritants. Periodontitis, if untreated, destroys the periodontal tissues and is a major cause of the loss of teeth in adults.

      The advances of periodontics have been mostly in techniques of treatment. It is believed that bacterial plaque, a soft layer of substances rich in bacteria that adheres to the teeth, is the factor responsible for most destruction of the gums and the tissues surrounding the teeth. Periodontists advocate removal of such plaque by a specific regimen of controlled hygiene.

prosthodontics

       prosthodontics is concerned with the restoration and maintenance of oral function, comfort, appearance, and health by the replacement of missing teeth and contiguous tissues with artificial substitutes, or prostheses.

      Prosthodontists have special training in the construction and placement of fixed (stationary) and removable appliances for the replacement of missing teeth. They also construct obturators, prosthetic devices designed to close off defects in the roof of the mouth in cases of cleft palate. A subspecialty of prosthodontics is maxillofacial prosthetics, which involves with the creation of appliances, composed of latex, silicone, or other modern materials, designed to replace portions of the face and jaws that have been lost because of surgery, disease, congenital disorders (congenital disorder), or accident.

      The proper fitting of oral prostheses requires a detailed knowledge of the anatomy of the head and neck, of the physiology of the neuromuscular system, and of the science of occlusion and jaw movements. It also requires skill in planning, mouth preparation, impression making, registration of jaw relations, try-in procedures, placement of the prostheses, and follow-up care.

oral and maxillofacial surgery

 Oral surgery deals with the diagnosis of, and the surgery required by, diseases, injuries, and defects of the human jaws and associated structures. Both dentists and physicians refer a wide variety of special dental problems to the oral surgeon. These may include the removal of impacted and infected teeth and the treatment of cysts (cyst), tumours (tumour), lesions, and infections of the mouth and jaws. In addition, there are more complex problems, such as jaw and facial injuries, cleft palate, and cleft lip.

Oral and maxillofacial pathology

      Oral pathology is the study of the causes, processes, and effects of oral disease, together with the resultant alterations of oral structure and functions. The oral pathologist provides diagnoses on which treatment by other specialists will depend.

endodontics

  endodontics deals with the treatment of diseases of the inside of the tooth, including the pulp chamber, the pulp canal, and contiguous structures. Root canal therapy and bleaching of nonvital teeth are standard treatments rendered by endodontists.

public health dentistry

      Dental public health is recognized as a specialty in Canada and the United States. The American Dental Association recognizes dental public health as a specialty if the holder of the master's degree proceeds to a further year of study in training and passes the examination of the American Board of Dental Public Health. Training in dental public health is also available in the United Kingdom. The specialty is not emphasized to the same degree in the rest of the world.

Oral and maxillofacial radiology

      Oral and maxillofacial radiology deals with the use of X-rays (X-ray) for diagnosis and treatment of diseases or disorders of the mouth and jaw. It embraces not only the standard X-ray but also the panographic X-ray, as well as the use of radiation and radioactive materials in treatment of disease of the mouth and jaws.

Cosmetic dentistry

      The face is the most recognizable feature of a person. The mouth, which includes the lips, cheeks, jaws, teeth, and gums (gum), makes up the lower third of the face. Cosmetic (or aesthetic) dentistry may offer profound benefits to the quality of life for those people who need it.

      Cosmetic dentistry may be classified as skeletal or dental. Skeletal changes may be achieved through oral surgery, which can change the position of the jaws. Dental changes may be achieved by either adding to, taking away from, or moving the teeth. The most common materials to add to teeth to change their appearance are bonding, a tooth-coloured plastic, or porcelain, a type of ceramic. Taking away tooth structure is accomplished with a drill. If only a slight amount of the tooth is removed, it is called sculpting or reshaping, and nothing is subsequently added. If a more substantial amount of tooth is removed, then porcelain may be added in a new position. Moving teeth is accomplished with braces, which can be either fixed or removable.

Reconstructive dentistry

      Reconstructive dentistry involves any major rebuilding of the mouth, typically with porcelain and metal. Reconstructive dentistry may be needed by individuals who have many severe cavities, have generalized severe gum disease, or have been in an accident. Reconstructive dentistry frequently involves a combination of all the dental specialties; patients may need multiple crowns (caps), gum therapy, root canal therapy, braces, or oral surgery, including dental implants.

      Reconstructions are planned to first stop the continuation of active disease and then repair the damage. Emotional components of treatment, such as fear, are frequently involved, and a dentist must be caring and have an understanding of psychology. Major potential sources of postoperative pain are often eliminated early in treatment by performing root canal therapy when indicated. The fabrication of final porcelain bridges usually begins 6 to 12 weeks following the completion of any necessary surgery. It is critical for patients to understand that reconstructed teeth require frequent cleanings and maintenance.

Implant dentistry

      A dental implant is an artificial tooth root. It serves to attach artificial teeth to the underlying jawbone. Dental implants may be visualized as screws, and the jawbone may be considered a piece of wood. Under this analogy, a screw would be turned half its length into a piece of wood, and an artificial tooth would be glued to the part of the screw projecting above the wood. The tooth would be firmly attached to the screw, which in turn would be firmly anchored in the wood. A single dental implant may be used for one missing tooth. Four to eight dental implants may be placed in a jaw that is missing all the teeth.

      Dental implants need to be placed in an adequate amount of bone that is free of infection. Sometimes surgical procedures are first necessary either to clean out existing infection or to create more bone for implantation procedures, such as bone ridge augmentation or nasal sinus elevation. The surgery to place the dental implants themselves is similar to that of tooth removal.

      Dental implant reconstructions can take 6 to 12 months to complete, mostly because of the healing time necessary between surgeries. Because bone is living tissue, it needs time to respond favourably to the biocompatible titanium implants. The biophysics of the early cellular response of the hard (bone) and soft ( skin and ligament) tissues to dental implantation is an area of intense research and debate. The benefits of this research carry over to orthopedics—for example, with the replacement of spinal rods and the healing of difficult broken bones, both of which require screws for immediate immobilization.

      Implant dentistry has evolved into a very predictable treatment option for many people.

Oral microbiology

      Oral microbiology, which is concerned with the effects of the more than 600 different species of oral bacteria on the teeth, gums, mouth, and other parts of the body that connect to the mouth through the digestive system (digestive system, human) and the circulation, is an important part of dental practice. Disease of the teeth and gums is generally bacterial in origin and can have a profound effect on general health. For example, the presence of certain species of bacteria in the gums can negatively influence the health of the heart and other important organs.

      A significant amount of research in dentistry focuses on oral microbiology. Vaccines (vaccine) to prevent cavities are being studied, and antibiotics (antibiotic) are used to treat periodontal (gum) disease. Vaccines and antibiotics work by suppressing or killing specific species of bacteria that have been identified as causative agents of disease.

Geriatric dentistry

      Geriatric dentistry is concerned with the oral health of elderly persons, who usually have significant medical problems and are taking multiple medications. In addition, they may have psychological and socioeconomic problems that require sophisticated dental management. A basic premise of geriatric dentistry is that elderly people often experience symptoms of dental decay and gingival (gum) disorders that differ from symptoms experienced by younger people. Dental treatment for the elderly is therefore geared to any physical and mental limitations they may have.

      Poor oral health in the elderly can lead to loss of appetite, malnutrition, metabolic disorders, and even, in cases of facial disfigurement, the onset of depression. Periodontal disease has been linked to heart disease, stroke, diabetes (diabetes mellitus), osteoporosis, and other illnesses. With the number of elderly persons of advanced age (85 years or older) with mental disorders such as Alzheimer disease reaching epidemic proportions, dental management of affected individuals has become a major challenge in clinical dental practice. The elderly often take many medications, which have adverse side effects such as dry mouth, a major cause of dental decay. The effects of aging result in changes in lip posture, chewing efficiency, and ability to swallow and taste and in an increase in diseases of the hard and soft tissues of the mouth.

      Although the majority of the elderly retain their natural teeth, dental decay, periodontal disease, and loss of teeth in individuals over the age of 65 have reached significant proportions. This backlog of oral disorders demands education, research, and advanced clinical training in geriatric dentistry.

Other disciplines

      There are several other disciplines in dentistry that, although not true specialties or subspecialties, are nevertheless the principal field of expertise of various dentists, who devote all or a major portion of their practice to these fields. Among them are oral medicine and forensic dentistry.

      Oral medicine, or stomatology, treats the variety of diseases that affect both the skin and the oral mucous membranes (mucous membrane). Some of these diseases, such as pemphigus vulgaris, can develop their first manifestations in the mouth and can be life-threatening. oral cancer also has a high mortality rate, partly because it grows in such close proximity to so many vital structures and readily involves them. With all such diseases of the oral cavity, removal of a portion of the lesion for examination under the microscope ( biopsy) by an oral pathologist is an essential procedure, and many other laboratory procedures are often also required for the diagnosis of oral mucosal diseases.

      Forensic dentistry is the study and practice of aspects of dentistry that are relevant to legal problems. It is a specialty practiced by few and is not usually part of dental education. Forensic dentistry is, however, of considerable legal importance for several reasons, one of the most important of which is the fact that the teeth are the structures of the body most resistant to fire or putrefaction. Moreover, the arrangement of the teeth or any restoration in them is virtually or completely unique to any given individual and, if dental records can be found, may enable identification with certainty similar to that provided by fingerprinting (fingerprint). For example, the identification of human remains after aircraft accidents can often be made only by this means. Minor irregularities of the teeth can also be reproduced in bite marks, which enables a suspect to be identified if he or she has bitten another person.

Dental education

Predental programs

      In a majority of countries in the world, undergraduate training in dentistry is available. Many require predental training prior to acceptance into a school of dentistry. The predental training is in addition to primary and secondary education, which usually takes from 10 to 12 years. The required number of years in predental education varies from one to seven (a number of European countries require from five to seven years of medical education before entering dentistry). Predental course training usually includes such studies as biology, chemistry, physics, and mathematics. Certain faculties of dentistry in Canada and the United States require a bachelor's degree in arts or science as a prerequisite for admission into a dental faculty.

Dental school and training

      After predental courses, training consists of four years in a faculty of dentistry to qualify as a doctor of dental surgery (D.D.S.) or doctor of dental medicine (D.M.D.), both degrees being equivalent. The program of studies during the four-year course includes the following biological sciences: human anatomy, biochemistry, bacteriology, histology, pathology, pharmacology, microbiology, and physiology, upon which the succeeding studies of the theory and techniques of dental practice are based. Studies required with respect to dental practice include restorative dentistry, prosthetics, orthodontics, surgery, preventive dentistry, medicine, dental public health (public health dentistry), pedodontics, periodontics, radiology, clinical practice, and anesthesia.

Ancillary dental fields

Dental hygienists

      The dental hygienist is a figure in the campaign to reduce periodontal disease and to improve physical well-being by promoting better care of the mouth.

      The prevention of oral disease through education and treatment is the chief function of hygienists. The specific duties and services that they are allowed to perform depend on the bylaws of the licensing bodies, the requirements of the dental offices in which they are employed, or the aims and objectives of the public health programs in which they are engaged. Hygienists generally work under the effective supervision of a qualified dentist. In some cases, hygienists are permitted to work without supervision.

      Hygienists employed in dental offices remove deposits and stains from the patient's teeth, apply fluorides, and observe and record conditions of decay and disease for the dentist's information. Further duties may include the taking of X-ray photographs of parts of the mouth, which the hygienist develops and mounts. Another function of the hygienist is to promote dental health by advising on diet and nutrition (nutrition, human) and encouraging oral hygiene.

      Hygienists employed by educational authorities assist school dentists by performing such duties as examining children's teeth. They may also visit classrooms to explain the importance of oral hygiene and to give instruction in the proper care of the teeth and gums. In hospitals they perform mainly the same duties as for private practitioners.

Dental nurses and dental auxiliaries

      In New Zealand, auxiliaries known as dental nurses (nursing) (or dental therapists) have been carrying out a dental care program for children for a number of years. Traditionally, a dental nurse receives minimal supervision but is equipped to provide a dental care program for children and adolescents up to 18 years of age. In the past, a degree in dental therapy required two years of specialized training. Today a university-level Bachelor of Oral Health degree has replaced programs in dental therapy in New Zealand. To obtain a bachelor's in oral health, students are trained in both dental therapy and dental hygiene for a period of three years.

Dental assistants

      The majority of dentists in private practice employ one or more dental assistants to provide such services as the reception of patients, the keeping of records and accounts, assistance for the dentist while he or she is treating patients, general upkeep of the office, developing of dental X-rays, and sterilization of instruments.

Dental technology

 Dental technicians, also called dental mechanics, make artificial crowns, bridges, dentures (denture), and other dental appliances according to dentists' specifications. Work orders, accompanied by models or impressions of patients' mouths, state the exact requirements for each particular job. In large laboratories the various stages of manufacture are often divided, and the technicians employed may specialize. Sometimes partially skilled persons are hired to work in limited aspects of production on an assembly-line basis.

Organizations

      In the United States, every state has its own dental society, which is subdivided into local societies. Membership in the local society automatically confers membership in the state society and the American Dental Association. In addition, the National Dental Association exists to represent ethnic minorities in dentistry in the United States. The National Dental Association was formed in 1932 by African American dentists, who were experiencing racial discrimination and were prevented from becoming members of organized dental societies. Today the American Dental Association will allow no form of racial bias to prevent membership. Dentists with similar interests have formed their own organizations, such as the American Association of Women Dentists, the National Association of Seventh Day Adventist Dentists, the American Academy of the History of Dentistry, and many others. In addition, every specialty has its own organization.

      Associations of dentists, dental journals, and dental schools exist in almost every country of the world. The Fédération Dentaire Internationale (International Dental Federation) was founded in 1900 and has met annually except in times of war. It has sponsored international dental congresses that are planned to meet every five years. Other international organizations include the Association Internationale pour la Recherche Dentaire (International Association for Dental Research) and the Association pour les Recherches sur les Paradentopathies (Association for Research into Periodontal Diseases), which was organized in 1932. The International Dental Journal, published by the Fédération Dentaire Internationale, was founded in 1950.

      Within the general framework of the World Health Organization, the dental health program has progressed steadily from the beginning. A proposal for a joint review of stomatology and dental hygiene in collaboration with the Fédération Dentaire Internationale was made at the first World Health Assembly in 1948.

      Certain organizations, including the World Health Organization and the Fédération Dentaire Internationale, and countries such as New Zealand and the United States offer assistance to many developing countries in the provision of health educational and dental care services. For example, New Zealand has long given developing countries the benefit of its experience in the use of dental auxiliaries (dental auxiliary), or what are commonly known as school dental nurses. Direct assistance is provided in the development of other public health dental services to countries such as Sri Lanka, Malaysia, Singapore, Brunei, Thailand, Indonesia, and Papua New Guinea. Dentists from these countries have had the opportunity to study the New Zealand system, and a number of school dental nurses have received their training there, enabling them to assist in the establishment of training facilities in their home countries.

Ralph A. Connor Malvin E. Ring Saul Kamen Jeffrey Dorfman

Additional Reading

History of dentistry

Pierre Fauchard, The Surgeon Dentist; or, Treatise on the Teeth, 2 vol. in 1 (1946, reprinted 1969; originally published in French, 2nd ed., 1746), is a classic work. Detailed accounts of the history of dentistry include Vincenzo Guerini, A History of Dentistry: From the Most Ancient Times Until the End of the Eighteenth Century (1909, reprinted 1967); and Bernhard Wolf Weinberger, An Introduction to the History of Dentistry, with Medical & Dental Chronology & Bibliographic Data, 2 vol. (1948, reprinted 1981). Malvin E. Ring, Dentistry: An Illustrated History, 3rd ed. (1992), is a readable comprehensive survey. A visual history of dentistry in America is presented in Richard A. Glenner, Audrey B. Davis, and Stanley B. Burns, The American Dentist: A Pictorial History with a Presentation of Early Dental Photography in America (1990).

Specialties of dentistry

J.W. Eveson and Crispian Scully, Color Atlas of Oral Pathology (1995), is a text and colour atlas. Oral and dental surgery is the subject of David A. Mitchell, An Introduction to Oral and Maxillofacial Surgery (2006). Other dental specialties are covered in Ralph E. McDonald, David R. Avery, and Jeffrey A. Dean, Dentistry for the Child and Adolescent, 8th ed. (2004); Thomas M. Graber, Robert L. Vanarsdall, and Katherine W.L. Vig, Orthodontics: Current Principles and Techniques, 4th ed. (2005); Richard E. Walton and Mahmoud Torabinejad, Principles and Practice of Endodontics, 3rd ed. (2002); Irving Glickman, Glickman's Clinical Periodontology, 7th ed., edited by Fermin A. Carranza (1990); and Kenneth J. Anusavice, Phillips' Science of Dental Materials, 11th ed., edited by Ralph W. Phillips (2003).

Public health dentistry

Brian A. Burt and Stephen A. Eklund, Dentistry, Dental Practice & the Community, 6th ed. (2005); and James Morse Dunning, Principles of Dental Public Health, 4th ed. (1986), are studies of the relationship between the dentist and society.

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