dentistry

dentistry is the art or science of treating diseases of the teeth and of the gums around them. As with medicine, dentistry is subdivided into a number of specialities. Oral surgery includes tooth extractions and operations on the jaw bones and the soft tissues of the mouth. Oral medicine deals with the treatment of local or systemic diseases affecting the mouth. Restorative dentistry involves replacement of parts of teeth or missing teeth. Fillings may be made from ‘plastic’ materials, such as amalgams or tooth-coloured composite resins, or pre-cast inlays; larger restorations may require metal or ceramic crowns. Restorative dentistry also includes endodontics (treating the pulps or root canals of teeth) and prosthodontics. In prosthodontics, missing teeth are replaced either with fixed bridges (using crowns placed on healthy teeth to support the ‘pontic’ that replaces the missing tooth or teeth) or removable dentures (false teeth) that may be partial or complete, depending on whether some or all of the natural teeth have been lost. Periodontics covers treatment of diseases of the gums (gingivitis) and other tissues around the teeth (periodontitis). Orthodontics is the correction of misalignment of teeth using appliances (‘braces’), which may be held by brackets glued to the teeth (fixed appliances) or retained with wire clasps (removable appliances). Paedodontics covers all aspects of dentistry in children.

The earliest references to teeth and dental diseases are inscriptions written on clay tablets around 5000 years ago in Mesopotamia. The first known dentist was Hesi-Re. He lived in Egypt around 3000 years ago, and was described as ‘the greatest of the physicians who treat teeth’. In ancient times, dental ‘treatment’ consisted mainly of tooth cleaning and perhaps some tooth extractions. Dentures (false teeth) first appeared in Sidon (Lebanon) and Tuscany around 630 bce. Here, gold bands and wires were used to attach false teeth (usually carved from ivory) to adjacent healthy teeth. The Romans were very oral hygiene-conscious. They washed their teeth and cleaned them with tooth powders (dentifrices). In ancient Greece and Rome, as in Egypt, dentistry was performed by general physicians. Practitioners were skilled in restoring carious teeth with gold and replacing missing teeth with false ones. These false teeth were ridiculed by the poet Martial, who wrote in the first century ad:
Lucania has white teeth; Thaïs brown. How comes it? One has false teeth, one her own.During the Dark and Middle Ages in Europe (approximately from 500–1500 ad), progress in medicine halted and there were no real advances for nearly 1000 years. However, during this period knowledge was sustained by Islamic scholars such as Albucasis, who wrote extensively on teeth and tooth cleaning. The importance of oral hygiene was widely recognized in the Orient. During this period Hindus and the Chinese developed various dental treatments and complex surgical procedures. In Europe, by the fifteenth century ‘dentistry’ was undertaken by barber–surgeons, physicians or apothecaries, blacksmiths, and other ‘tooth-drawers’. Herbal concoctions were the main ‘remedies’ for toothache and ‘treatment’ was confined mainly to extractions. The upper classes cleaned their teeth with cloth or sponges, and some even had gold or silver toothpicks. These were often hung round the owner's neck as an item of jewellery.

Knowledge blossomed in the Renaissance. Many of the new anatomical texts, such as Andreas Vesalius' great work De humani corporis fabrica, contained sections on teeth. Some purely dental texts were published in the sixteenth and seventeenth centuries, but the foundations of modern dental practice were laid in Pierre Fauchard's Le Chirurgien Dentiste (1728). Fauchard's book was a comprehensive discourse on a wide range of treatments. He described techniques for scraping out caries and filling the cavities with soft metals such as tin, lead, or gold. His book also gave rise to the modern term ‘dentist’ or ‘dental surgeon’.

Prior to 1844, there were no anaesthetics to abolish the pain of surgery. However, opium and laudanum (tincture of opium) were freely available ‘over the counter’. Dorothy Wordsworth (sister of the poet William) wrote: ‘I had toothache in the night. Took laudanum.’ In 1844, an American dentist, Horace Wells, was the first person to experience tooth extraction under nitrous oxide analgesia. Two years later, William Morton extracted a tooth under ether anaesthesia. In 1884, a Dr Nash was the first person to fill a tooth using cocaine injected as a local anaesthetic. In 1905, cocaine was replaced by the synthetic drug novocaine (procaine). This in turn was replaced by lignocaine (lidocaine), which is in use today.

In the eighteenth century, dentures were hand-carved from materials such as ivory, and so did not fit well. Springs were sometimes used to help improve the stability of these loose dentures. However, dentures did not improve until the invention (by Nelson Goodyear) of a hardened rubber (‘Vulcanite’) which allowed closely-fitting denture bases to be constructed on casts made from impressions of the patient's mouth. As well as fitting better, vulcanite dentures were cheaper to make.

Other developments in the nineteenth century included the reclining dental chair, amalgam fillings (which were controversial even in the 1850s), and the treadle engine for driving the dental drill. The first electric-powered dental drill was invented in 1868. Many of the technical aspects and skills of dentistry were established by the end of the nineteenth century and some have remained more or less unaltered to the present day. The principles of cavity cutting, formulated by G. V. Black in the 1880s, have been supplanted only recently with the advent of adhesive filling materials. Developments in the twentieth century included improvements in dental materials, the introduction of the ‘high-speed’ drills (powered by compressed air), and greater emphasis on instrument sterility and cross infection control.

The modern dentist is part of a team, which includes a dental nurse (dental assistant), a technician, and ancillary operators such as dental hygienists, dental therapists, and dental radiographers. Dentistry is changing from being a pain-relief and patch-up service to a profession which places emphasis on prevention of tooth decay (dental caries) and gum disease (gingivitis and periodontitis). These diseases are largely preventable with good diet and effective oral hygiene. Their effects can be minimized by early diagnosis and treatment. Fluoride can help prevent caries, by making the enamel more resistant to attack by plaque acids, but it can also cause staining or mottling of the teeth (fluorosis). Artificial fluoridation of water supplies would reduce the incidence of caries, especially amongst people with poor standards of oral hygiene. However, fluoridation of public water supplies is a controversial political issue. The recent improvements in dental health can be illustrated by data from Great Britain. In 1968, 37% of adults in England and Wales had no natural teeth. In Scotland in 1972, 44% of adults had lost all their teeth. By 1988, these figures had fallen to 20% in England and Wales and 26% in Scotland. These improvements were due mainly to the better dental health in people under 35 years of age.

In spite of these improvements in dental health, teeth are still extracted because of decay. General anaesthesia (GA) was widely used for tooth extraction in young children and in some adults with a fear of injections. In the UK, the use of GA for dental procedures has been restricted. This is intended to eliminate the small numbers of deaths each year associated with dental GA. Since 1998, GA can be administered only by suitably qualified anaesthetists in clinics where proper emergency facilities and staff are available. One alternative to GA is conscious sedation. Here, the patient is awake and can respond to verbal commands, but is ‘relaxed’. Sedation is produced using drugs such as a nitrous oxide– oxygen mixture, or tranquillizers such as diazepam (Valium), and is normally used along with appropriate local anaesthesia.

What of the future? The improvements in dental health must be sustained. A major priority is to find effective alternatives for injected local anaesthetics and replacements for the dental drill. One interesting area of development is the use of chemicals to remove caries without the need for drilling. The decay is dissolved by acids and the softened debris is scooped out. Laser technology, too, is developing and in time may replace the drill in restorative dentistry. The advent of adhesive, tooth-coloured fillings has revolutionized restorative dentistry. It is no longer necessary to cut large cavities for amalgam fillings. Instead, fillings can be placed with the minimum loss of healthy tooth substance. In prosthodontics, metal posts implanted in the jaw bones can be used to improve the support and efficiency of dentures. Nowadays, people live longer and can expect to have their natural teeth when they die. The science of dental gerontology has emerged to meet the dental needs of elderly people. Cosmetic dentistry, too, is a growth industry. Thin veneers can be used to correct defects on the outer surfaces of anterior teeth. The current trend of body adornment has extended to teeth, and small gems or gold shapes (‘Twinkles’) can be glued to the tooth surface. But cosmetic dentistry is not new. Many societies in Africa and America file the teeth for decorative and ceremonial purposes. In the ninth century the Mayans placed decorative inlays in anterior teeth. These inlays of semi-precious stones were fixed into cavities cut with a simple bow drill. Such skills were not introduced to Europe until many centuries later.

Robin Orchardson

Bibliography

Hillam, C. (1990). The roots of dentistry. British Dental Association, London.
Ring, M. E. (1993). Dentistry: an illustrated history. H. N. Abrams Inc., New York.

See also teeth.