Technical Advances
Among the most outstanding technical achievements was that of Giuseppe Angelo Fonzi, who, in 1806, constructed individual artificial teeth with metal pins in each tooth for attachment to the denture base. He also introduced the practice of shading or coloring artificial teeth to resemble natural teeth. In 1847, Edwin Truman introduced gutta percha as a temporary filling material, and in 1886, C. H. Land developed a method of making dental crowns of porcelain. A special chair for dental operations was introduced in 1865, and the electric dental drill was devised in 1883.
In 1854, Thomas Evans, an American dentist practicing in Paris, made a vulcanite rubber denture base for Charles Goodyear, who had procured a patent for vulcanizing rubber in 1851. Vulcanite was relatively inexpensive and easy to mold and soon became widely used as a denture base. Norman Kingsley devised vulcanite plates with attachments for correcting overcrowded teeth, and in 1879 published A Treatise on Oral Deformities as a Branch of Mechanical Dentistry. In 1895 another American dentist, Greene Vardiman Black, perfected silver amalgam as a material for filling cavities. Silver amalgam is an alloy consisting mainly of silver, mercury, and tin, and unlike other metals that had been used, amalgam does not expand or shrink after it is placed in the cavity. Black also recommended that a dental cavity should be enlarged before it is filled in order to prevent the recurrence of decay.
In 1888 the first book exclusively devoted to orthodontics was published by John N. Farrar, and in that same year, Edward H. Angle devised a system for classifying malocclusions. Angle, who in 1890 became the first dentist to limit his practice entirely to orthodontics, founded the Angle School of Orthodontia and the American Society of Orthodontists.
Anesthesia
Probably the most important dental and medical achievement in the 19th century was the development of anesthesia. Since earliest times, humans have been constantly seeking means to alleviate pain, and with the progress of surgery the need for anesthetic agents became acute. Nowhere was this lack felt more than in the extraction of teeth. Although alcoholic drinks, hypnotism, and narcotics, such as opium, were sometimes used to relieve pain during operations, most tooth extractions were performed without the use of anesthetics. Then, in the 1840s, two American dentists, Horace Wells and William Thomas Green Morton, introduced the use of two anesthetics -nitrous oxide (laughing gas) and ether.
In 1844, Wells, while under the influence of nitrous oxide gas, had a tooth extracted from his mouth and reported feeling no pain during the operation. Wells subsequently used nitrous oxide gas on a number of patients undergoing extractions. However, when he administered it to a patient in front of an audience composed largely of dentists, physicians, and students, the patient was heard to groan after the tooth was removed, and the experiment was considered a failure even though the patient later admitted that he had felt no pain.
Morton, who had been a student of Wells', was present at the demonstration and was determined to continue experimenting with the gas but was unable to obtain any nitrous oxide. At the suggestion of Charles T. Jackson, a physician and chemist, he began working with ether and in 1846 he successfully demonstrated the value of this gas as an anesthetic agent. Wells' contribution to the development of anesthesia was nearly forgotten for a number of years, but in 1864 the National (later American) Dental Association declared him to be the real discoverer of anesthesia.
Professional Status
The development of dentistry as a recognized profession was evidenced by the establishment of national dental organizations, dental schools, and licensing practices in many countries. In the United States, two physicians who also practiced dentistry, Horace H. Hayden and Chapin A. Harris, tried to establish a department of dentistry at the University of Maryland. When their efforts failed, they established the Baltimore College of Dental Surgery, the world's first dental school. The school was founded in 1839 and in 1841 it granted its first degrees, the Chirurgiae Dentium Doctor (Doctor of Dental Surgery, or D.D.S.). This first dental school met with much opposition. For many years the students considered those studies not directly concerned with the mechanical phase of dentistry to be a waste of time, and such subjects had to be made compulsory to ensure the attendance of students.
Although the demand for dental services increased steadily in the United States as the population grew, there was only a very small change in the type of men practicing dentistry for many years after the Baltimore College of Dental Surgery was founded. The public demand for dentists who had graduated from dental school was practically nonexistent until after the Civil War. Even by 1870 there were only about 1,000 graduates of dental schools in the United States, while the total number of practicing dentists was close to 10,000. Slowly, the need for qualified dentists led to the founding of numerous dental schools, and by 1960 there were 87 dental colleges in the United States. These included the Harvard Dental School, which was founded in 1867, and the University of Pennsylvania School of Dentistry, established in 1878. With the rise of dental schools came the establishment of several dental clinics, including one in New York City (1849), one in Philadelphia (1861), and another in Boston (1867).
The world's first national dental association and first dental journal were also established in the United States during the 19th century. The first dental journal, the American Journal of Dental Science, was founded in 1839, and the following year the American Society of Dental Surgeons was established. Other associations and publications soon followed, furthering the communication of ideas among practicing dentists. The first American textbook on dentistry, A Treatise on the Human Teeth, was published in 1801 by R. C. Skinner, and dental journals published by dental supply manufacturers and dealers appeared in 1847, when the S. S. White Company published the Dental Newsletter. In 1859 the name of this publication was changed to Dental Cosmos, and in 1937 it merged with the Journal of the American Dental Association.
The first state to enact legislation relating to the practice of dentistry was Alabama, which, in 1841, passed restrictions regulating the licensing of dentists. Forty years later, 12 states had similar laws, and by 1900 this figure had risen to 37. In 1880 the dentists of the District of Columbia tried to obtain federal legislation to govern the practice of dentistry but their attempt failed. It was not until 1891 that a bill was passed changing the United States census classification of dentists from technicians to professional men.
The founding of dental schools, societies, and professional journals in the United States was followed by similar developments in other countries. In England, the College of Dentists was founded in 1857, and the following year the London School of Dentistry was organized. In 1880 the British Dental Association was founded, along with the British Dental Journal. In France two dental associations were founded in 1879, and the first French dental school was established in 1880. In Germany the first dental journal was founded in 1849, and 10 years later the first national dental organization was formed. The first German dental school was founded in 1884, and many others were soon established.
Advances in Related Fields
Toward the close of the 19th century there was an increasing appreciation of the many advances made in the field of biology and other related sciences, and many of these advances were successfully applied to the field of dentistry. The announcement in 1860 by Louis Pasteur of the germ theory and Robert Koch's development of a technique for growing cultures of bacteria in the laboratory initiated the study of bacteria as a cause of dental decay. One of Koch's students, Willoughby Miller, was among the first to investigate this area of research, and in 1890 he published his findings in the book Microorganisms of the Human Mouth. In this book Miller stated that fermented food particles lodged between and on the teeth produce an acid that penetrates the enamel of the teeth and permits the microorganisms in the mouth to attack the protein matrix, or ground substance, of the enamel, thus producing dental cavities.
In 1896 J. Leon Williams stated that dental decay is a result of acid acting on a particular spot of a tooth under a gelatinous plaque that prevents the spot from coming in contact with the saliva in the mouth. Williams advocated the frequent and thorough cleaning of the teeth and introduced the slogan, "A clean tooth never decays." Although the validity of this statement is questionable, Williams' theory led to an increase in the practice of proper mouth hygiene.
Another major scientific advance in the late 19th century was the discovery of X-rays in 1895 by Wilhelm Roentgen. The following year, C. Edmund Kells of New Orleans, La., and Otto Walkhoff of Munich, Germany, made the first X-rays of the teeth. At first, dental X-rays were used primarily to detect impacted teeth and other teeth that fail to erupt normally but soon dentists began using them to diagnose dental caries, deformities of the jaw bone, and other disorders of the mouth.
