Table of Contents

Practice Building
Periodontics

Inside Dentistry

May 2009, Volume 5, Issue 5
Published by AEGIS Communications

The Stellar Names of Dentistry and Their Wonderful Inventions

Nayda Rondon

From earliest times, individuals have been plagued with dental problems and have sought various means and methods—sometimes fanciful, impractical, or awkward; other times ingenious, clever, and revolutionary—to remedy them. By the Middle Ages, European barber-surgeons were learning and progressing by trial and error. Perhaps inspired and fueled by Pierre Fauchard's pivotal treatise Le Chirurgien Dentist ou Traité des Dents, which firmly established dentistry as a valid and respected profession, the spirit of innovation and achievement accelerated at an exciting pace during the 18 th century. Since then, numerous inquisitive and enterprising minds have added their immeasurable contributions along the way.

Yet, while each achievement has helped to collectively advance the profession of dentistry, all too often many—if not most—of these creative dental visionaries remain largely unsung for their great contributions. "Today the profession of dentistry is looked upon by the public with respect and admiration," notes Malvin E. Ring, DDS, MLS, FACD, author of Dentistry, An Illustrated History. "Yet some dental specialists and many laymen know nothing about the struggles that took place to advance the profession or the great contributions that have been made by dentistry to human welfare."

It is only fitting to look back in recognition and respect. "The only guide to what lies ahead is the study of the past," emphasizes Dr. Ring. "How much more important it is to be aware of our historical antecedents today, when changes are occurring so rapidly that only by keeping our eyes steadily on what went before can we progress with intelligence and confidence."

" Most inventions are a series of improvements to an idea or concept and evolve over time," notes Scott Swank, DDS, curator of The Dr. Samuel D. Harris National Museum of Dentistry in Baltimore, Maryland.

While it is not possible in this timeline to recognize each and every individual who impacted the field of dentistry, Inside Dentistry offers an overview of some of the stellar names and their invaluable contributions in the hopes that their individual inventions and/or improvements will serve as a collective tribute and testament to the determination, talent, dedication, conviction, motivation, and perseverance of all in the profession.

Inspired by those who came before and with the solid foundations of centuries' worth of achievements, today's visionaries and innovators can build upon the groundbreaking milestones of the past to create promising new bridges to the continued evolution of dentistry. Without doubt, the accomplishments of the past will propel us ever forward into even loftier and more ambitious innovations that will carry the field of dentistry well into the 21 st century and beyond.

Who: William Addis
What: First mass-produced toothbrush (Figure 1)
When: 1780
Where: Clerkenwald, England
Purpose: To clean teeth

Comments: In 2003, the toothbrush was chosen as the number one invention Americans could not live without, beating out the automobile, computer, cell phone, and microwave oven, according to the Lemelson-MIT Invention Index.1

Evolution: The first American to patent a toothbrush was H. N. Wadsworth and many American companies began to mass-produce toothbrushes after 1885. The Prophylactic brush, made by the Florence Manufacturing Company of Massachusetts, is one example of an early American-made toothbrush. The Florence Manufacturing Company also was the first to sell toothbrushes in boxes. In 1938, DuPont manufactured the first nylon bristle toothbrushes.2 Currently, the brands, styles, and colors of toothbrushes available are vast. A study of worldwide patent applications between the years 1963-1998 showed about 3,000 toothbrush patents. 3

Who: Nicolas Dubois de Chémant
What: Porcelain teeth
When: 1789
Where: Paris, France
Purpose: To eliminate the reliance on human, animal, and carved ivory as tooth replacements

Comments: This French dentist teamed up with Alexis Duchteau, a Parisian apothecary, to come up with one-piece dentures. After Duchteau lost interest, Dubois de Chémant persevered, working to perfect the invention. In 1789, Dubois de Chémant presented his invention to the Académie des Sciences and the faculty of medicine of Paris University, and received a royal patent from Louis XVI.

At this point, Duchteau, claiming that Dubois de Chémant had stolen his invention, asked that the patent be revoked, but the courts upheld the validity of Dubois de Chémant's patent. After fleeing the French Revolution and traveling to England in 1792, Dubois de Chémant applied for and received a 14-year English patent for the exclusive manufacture of "mineral paste dentures," which he called "incorruptibles," a term that for many years became synonymous with porcelain teeth. 4(p180-181)

"Dubois de Chémant played a major role in the advancement of prosthetic dentistry," notes Ring. "His dentures remained popular until the introduction of individually baked porcelain teeth by Giuseppangelo Fonzi in the next century."

Evolution: "Improvements in porcelain manufacturing techniques would eventually lead to lifelike and very functional artificial teeth," comments Swank.

Who: John Greenwood
What: Dental foot engine (Figure 2)
When: 1790
Where: United States
Purpose: Increases the rotation of a drill and frees up dentist's hands; significantly improves the efficiency with which diseased material is removed from a tooth

Comments: Greenwood was one of George Washington's dentists. Greenwood pioneered the use of foot power drills.

Evolution: It wasn't until the 1871 invention of the foot-treadle engine design by James Beall Morrison, which was manufactured commercially, that the foot-treadle dental engine became the standard for use in operative dentistry, notes Swank. "Its widespread use after 1871 was as revolutionary then as the introduction of the air turbine was in 1957," he comments. It paved the way for the air turbine and lasers with the ability to cut tooth structure.

Who: Josiah Flagg
What: Dental chair (Figure 3)
When: 1790
Where: Boston, Massachusetts
Purpose: To facilitate a dentist's access and convenience during dental procedures, while also enhancing patient comfort and increasing efficiency for the dentist

Comments: It was the first chair specifically modified for dental use in the United States. A prominent American dentist who also received silversmith training from Paul Revere (particularly its use in dentistry), Flagg adapted a wooden Windsor chair by attaching an adjustable headrest and an arm extension that held dental instruments.

Evolution: Rudimentary but serviceable, the original chair was used by three generations of Flagg dentists. Numerous other models—such as this circa 1890 chair—came after it. They were all precursors of today's sophisticated and high-tech dental chairs.5

Who: Giuseppangelo Fonzi
What: Molds to create individual porcelain teeth
When: 1808
Where: Paris, France
Purpose: Replace missing teeth

Comments: This Italian dentist with a fashionable Parisian practice invented the individual porcelain teeth that revolutionized the construction of dentures in the early 19th century. 4(p211)

Evolution: His invention made modern prostheses possible, according to Ring. "Subsequently, other technicians improved Fonzi's artificial teeth, making their color more lifelike by baking them of different earths and perfecting their shape by carving the molds more skillfully." 4(p204)

Who: Levi Spear Parmly
What: Dental floss
When: 1815
Where: New Orleans, Louisiana
Purpose: Cleaning food debris remaining in between teeth

Comments: Parmly is commonly credited as being the "inventor" of modern dental floss when he promoted flossing teeth with a piece of waxed silk thread.

Evolution: In 1882, the Codman and Shurleft Company of Randolph, Massachusetts, started to mass-produce unwaxed silk floss for commercial home use. The Johnson and Johnson Company of New Brunswick, New Jersey, was the first to patent dental floss in 1898. During World War II, Dr. Charles C. Bass—largely responsible for making teeth flossing the important part of dental hygiene that it is today—developed nylon floss as a replacement for silk floss.2

Who: Samuel Stockton White
What: Commercial manufacture of porcelain teeth (Figure 4)
When: 1825
Where: Philadelphia, Pennsylvania
Purpose: To mass produce false teeth and make them available to large numbers of people in a faster, more economical manner

Comments: A Philadelphia jeweler, Stockton was the first to factory-produce porcelain teeth in quantities.

Evolution: White's S.S. White Dental Manufacturing Company established and dominated the dental supply market throughout the 19 th century. It eventually became the world's leading dental manufacturing company. 4(p206)

Who: James Snell
What: Reclining dental chair (Figure 5)
When: 1832
Where: United States
Purpose: To facilitate dentists' access and convenience during dental procedures, while also enhancing patient comfort

Comments: "The chair was well upholstered and had a spirit lamp and mirror ingeniously arranged to cast and reflect light into the mouth," notes Ring, while Swank adds that it was "the first to have an adjustable seat and back."

Evolution: For many years dentists continued using ordinary chairs to which they attached a kind of portable headrest introduced in 1847 by Jones, White and Company. In the 1850s and 1860s, various companies began manufacturing full dental chairs. In 1871, the S.S. White Dental Manufacturing Company introduced the first all-metal dental chair that could be raised or lowered by means of a crank attached to a central screw (Figure 6). The first pump-type hydraulic chair (known as the Wilkerson chair) came out in 1877. It offered a compensating backrest (one that moves to maintain the same position relative to the patient's back). 4(p255)

Who: Horace Wells
What: Nitrous oxide
When: 1844
Where: Connecticut
Purpose: Anesthetic

Comments: Wells discovered the anesthetic benefits of nitrous oxide and used it in his private practice to conduct several successful extractions. 6 "He is credited as being the discoverer of anesthesia, one of the greatest medical discoveries of all time," notes Dr. Ring.

Evolution: Commonly known as "laughing gas," nitrous oxide came into general use—particularly among dentists—in the United States in the 1840s as an anesthetic. 7

Who: Robert Arthur
What: Originates the cohesive gold foil method (Figure 7)
When: 1855
Where: Baltimore, Maryland
Purpose: It allowed dentists to insert gold into a cavity with minimal pressure; made the resulting gold restoration able to contain the natural contours of the tooth, notes Swank.

Comments: While he was not the first to use gold as a tooth filling material, Arthur did discover that by heating the gold foil, impurities could be driven off and the gold could be made to adhere to itself.

The foil is fabricated by annealing, a process of passing gold through a flame to make it soft and malleable. However, the cavity had to be free of saliva for perfect cohesiveness. This problem was not overcome until the invention of the rubber dam in 1864 (see below).

Evolution: In the succeeding years after this major advance in dentistry, there were minimal changes in the direct gold process. The use of direct gold is no longer commonplace due to its high technique sensitivity, demanding regime, and high placement time, as well as the development of high-quality composite resin materials. 8

Who: Charles Goodyear
What: Patented a process for making dental plates out of vulcanite (hard rubber) (Figure 8)
When: 1855
Where:United States
Purpose: Denture base material

Comments: Nelson Goodyear invented a process for making vulcanite or hard rubber in 1851; Charles Goodyear patented a process for making dentures out of this material in 1855. Patent infringements and licensing fees caused heated battles for more than 25 years. Nevertheless, t hese vulcanite dentures were the first functional, durable, and affordable dentures, marking a great advance in dental treatment.

Evolution: Vulcanite revolutionized the field, and within a very short time supplanted gold as the material of choice in the construction of denture bases, notes Ring. 4(p242) The fit of these bases allowed self-retaining dentures, making earlier spring-type dentures obsolete. Used from 1855 until after World War II, vulcanite was the best and most widely used denture base material until the invention of acrylic, says Swank.

Who: Charles Stent
What: Develops impression (modeling) compound
When: 1857
Where: England
Purpose: To make impressions

Comments: This modeling compound was an attempt to improve gutta percha by adding a red colorant; stearine, a substance made from animal fat, to improve plasticity and stability; and talc, used as an inert filler to strengthen and texturize. 9,10

Evolution: This became a common material to use for making impressions. Copper bands or other devices were used in the late 1800s, along with impression compound, to make impressions for full crowns. Over the years, the formulation of impression compound has been enhanced, and it is still in common use in clinical dentistry. 8

Who: Sanford C. Barnum
What: Rubber dam (Figure 9)
When: 1864
Where: New York
Purpose: Isolates a tooth from the oral cavity

Comments: A simple device made of a piece of elastic rubber fitted over a tooth by means of a metal frame, it creates a dry field in which the dentist can work.

Evolution: "It greatly improved the ability of dentists to successfully fill teeth with gold," explains Swank. This was crucial to the proper placement of cohesive gold foil restorations, developed a short time before.

Who: James Beall Morrison
What: Patents first commercially manufactured foot-treadle dental engine (Figure 10)
When: 1871
Where: St. Louis, Missouri
Purpose: Provides speed to a bur so it can smoothly cut enamel and dentin

Comments: " His monumental invention of the foot-powered drill allowed dentists to place restorations that were theretofore impossible. Dentists the world over became able to treat patients more comfortably and satisfactorily, and with less stress to themselves," according to Ring.

Evolution: Morrison turned manufacture of the drill over to Johnston Brothers, a manufacturing firm in New York City, and the first drill was sold at a dental convention in Binghamton, New York, on April 17, 1872. Soon after Morrison's dental engine was patented, the S.S. White Company improved on Morrison's design by introducing a flexible cable in which strands of wire were woven from both directions; this eliminated the chance of dangerous backlash. 4(p251) In the original model, the handpiece was attached directly to a gear that was turned by the endless belt. The new model had a flexible shaft between the handpiece and the belt-driven gear, allowing for greater flexibility and ease of operation. The Morrison drill operated at 600 to 800 revolutions per minute (rpm); modern dental drills, turbine-powered, rotate at speeds of up to around 400,000 (rpm).11

Who: George F. Green
What: Patent for first electric dental engine
When: 1871
Where: Philadelphia, Pennsylvania
Purpose: To remove sections of decayed teeth faster and more efficiently

Comments: Featuring a self-contained motor and handpiece, it was complex in its construction. It was largely limited in its early use by the lack of reliable electric power in various parts of the country, notes Swank. Moreover, it was heavy and clumsy and developed little torque, adds Ring.

Evolution: The S.S. White Company put Green's electric-powered drill on the market in 1872. Despite many improvements made in the electric drill over the next decade, the majority of dentists continued to use the foot-driven drill because most offices in the country were still not electrified. It wasn't until the late 1880s that Dr. C. Edmund Kells became the first to bring electricity to his office. 4(p251)

Who: No single inventor has ever been identified, according to Swank. "Dentifrice, the term used for any chemical mixture used as a tooth cleaning aid, had recipes dating back to the Greeks and Romans," he explains.
What: Modern toothpaste (Figure 11)
When: 1800s
Purpose: To clean and maintain the health and esthetics of teeth

Comments: Tube packaging was patented in 1841 and used primarily for artist's paints. In 1887, F.A. Sarg's Son Company of Vienna, Austria, was granted approval to sell Kalodont dentifrice in tubes, making it the first toothpaste sold in a tube.

Evolution: In 1824, a dentist named Peabody (his full name has been lost) was the first person to add soap to toothpaste. John Harris first added chalk as an ingredient to toothpaste in the 1850s. In 1873, Colgate-Palmolive mass produced the first toothpaste in a jar. In 1892, Dr. Washington Sheffield of Connecticut manufactured toothpaste—Dr. Sheffield's Creme Dentifrice—in a collapsible tube. In imitation of Sheffield's product, Colgate Dental Cream was packaged in collapsible tubes in 1896. Advancements in synthetic detergents made after World War II allowed for the replacement of the soap used in toothpaste with emulsifying agents, such as sodium lauryl sulphate and sodium ricinoleate. 2 Developments and refinements continued to be made. In the 1950s, for instance, American Dental Association (ADA)-approved fluoride toothpastes were introduced.

Who: C. Edmond Kells
What: Adapted the discovery of x-rays to dentistry (Figure 12)
When: 1896
Where: New Orleans, Louisiana
Purpose: Allowed dentists to visualize the interior of a tooth for the first time

Comments: "The development of x-ray photography, or radiography, ranks only slightly less in importance than the discovery of anesthesia in the progress of the healing arts," remarks Ring.

The application of the x-ray (discovered by Wilhelm Conrad Röntgen in Wrzburg Physical Institute, Germany, in 1895) as a diagnostic dental tool was made possible by the pioneering work of New Orleans dentist C. Edmond Kells. A curious and gifted inventor with more than 30 patents, Kells took the first dental x-ray of a living person in the United States in 1896. Tragically, because of years spent holding the x-ray film with his fingers, he developed cancer and spent the last 20 years of his life battling the disease before taking his own life at the age of 72. 4(p273)

Evolution: Despite wide acceptance in the medical field, X-ray machines were not commonly seen in dental offices until the 1920s. Panographic and tomographic X-ray systems were later developed, and ultrasonics and PET scans also are used in the medical field. Additionally, non-film x-ray sensors now are being more commonly used in dentistry.

Who: Greene Vardiman Black
What: Development of usable amalgams (Figure 13)
When: Around 1900
Where: United States
Purpose: To repair cavities quickly and inexpensively

Comments: Black essentially revolutionized the profession of dentistry by standardizing the repair of teeth and making dentistry affordable to all. He is also recognized for his famous "extension for prevention" principle, which holds that dentists should incorporate more grooves and pits than those currently exhibiting decay as a preventive measure.

Evolution: "With G.V. Black's amalgam and tooth preparation system, for the first time it was possible to successfully repair cavities quickly and inexpensively in the general population. While other restorative materials such as gold foil and gold inlays were also in successful use during that period, they were not as widely used because of the time required and the cost. Throughout most of the 20 th century, dental amalgam was the predominant material for the general repair of carious teeth," writes Terry Wilwerding, DDS, MS, FACD. 12 Today, silver amalgam remains the world's most popular tooth filling material.

Who: Charles Land
What: Porcelain jacket crown
When: 1903
Where: Detroit, Michigan
Purpose: Esthetic and restorative

Comments: Helped by the invention of the electric furnace in 1894 and of low-fusing porcelain in 1898, Land was able to construct a full-porcelain crown built up on a platinum matrix. 4(p246) Similar in character to porcelain veneers, this type of crown is more esthetic because it is cemented to the tooth, has greater depth of color, and is opalescent.

Evolution: This invention laid the foundation for today's realistic-looking, strong, and durable cosmetic dentistry materials and advances.

Who: Alfred Einhorn
What: Procaine (Figure 14)
When: 1905
Where: Germany
Purpose: Later marketed under the trade name Novocain ® , procaine is a highly effective and safe local anesthetic.

Comments: Before the discovery of procaine, cocaine was the most commonly used local anesthetic. Apart from being highly addictive, cocaine's toxicity raised concerns in the medical profession. With his advancement, Einhorn ushered in a new era of safer, more reliable anesthetics.

Evolution: Procaine was widely used by physicians and dentists into the 1950s. The development in 1943 of lidocaine (Xylocaine®), which was even safer than procaine, saw a gradual shift. Still in use today, procaine now vies with many other local anesthetic agents currently employed; lidocaine remains the principal anesthetic in routine use in today's dental offices. 8

Who: William H. Taggart
What: Technique for "lost wax" casting machine
When: 1907
Where: Chicago, Illinois
Purpose: Allows a dentist to make precision cast fillings

Comments: Taggart's technique was called the "disappearing wax" technique. With centrifugal force replacing gravity as a method of filling the casting image inside an investment, it became possible to cast small, highly detailed objects. He patented this technique but lost his patents when it was discovered that Dr. B. F. Philbrook of Denison, Iowa, had written an article entitled "Cast Fillings" about gold inlay castings 25 years earlier, notes Dr. Wilwerding. 12

Evolution: Although systems somewhat paralleling his were in existence in the 1890s or before, Taggart's was revolutionary and considered o ne of restorative dentistry's greatest achievements. Thanks to Taggart, dentists were able to cast gold crowns and inlays with precision. Further refinements followed, including the introduction (also in 1907) of the centrifugal casting machine by Jamieson. Shortly thereafter, accurate methods for controlling expansion and contraction were developed, leading to the ability to fabricate highly precise castings. Since then, inlays and onlays made of high-strength composite materials and porcelain have been introduced. In 1985, the first ceramic inlay made by a chairside CAD/CAM device was cemented into a patient's tooth. In 2000, the CEREC 3 ® was introduced. This latest system provides a means by which a sophisticated ceramic inlay or onlay can be fabricated, with a handheld scanner reading the details of the preparation and software subsequently being used to drive the mechanism to precision-grind a restoration without the use of an impression or a second dental appointment. 8

Who: No one individual
What: Fluoride in toothpaste
When: 1914
Where: United States
Purpose: To prevent cavities and tooth decay

Comments: In 1914, fluoride was first added to toothpastes, but its use was criticized by the American Dental Association (ADA). Refinements continued and fluoride toothpastes developed in the 1950s received the ADA's approval.

Evolution: In the early 1940s, Procter & Gamble began a research program to seek ADA approval of fluoride in toothpaste. In 1950, the company initiated a joint research project with Indiana University. Headed by Dr. Joseph Muhler, the project team worked to develop and refine a safe and effective new toothpaste with fluoride, and in 1955, Procter & Gamble launched Crest, the first clinically proven fluoride toothpaste. 13 Since then, numerous other fluoride toothpastes have come on the market and earned the ADA seal of acceptance. The widespread use of such toothpastes has led to increased oral health in adults and children (over the age of 2) nationally and globally.

Who: Charles S. Venable and Walter G. Stuck
What: Adapted Vitallium, the first biocompatible implant metal, inside the body
When: 1936
Where: United States
Purpose: Its corrosion-resistant properties make it attractive for denture implants.

Comments: A year after Venable and Stuck developed Vitallium, Alvin Strock inserted the first Vitallium dental screw implant.

Evolution: Since it was introduced, dentists have come to prefer Vitallium to create superior function, fit, and esthetics for premium partial dentures.

Who: Oskar Hagger
What: System of bonding acrylic resin to dentin
When: 1949
Where: Switzerland
Purpose: Bonding

Comments: "Hagger's ground-breaking concept makes him the true ‘Father of Modern Dental Adhesives,'" notes K. J. Söderholm.14

Evolution: Other investigators soon adopted Hagger's concept, and different generations of dental adhesives have evolved as a consequence. "Today, after many years of accepting that the key to the success of dental adhesives is the micromechanical retention resulting from acid-etching of dentin and enamel, we still return to Dr. Hagger's original concept that bonding can be achieved via molecular interactions between adhesives and tooth surfaces. That concept is obvious in the development of newer generations of dentin adhesives. These adhesives, like Sevriton Cavity Seal, rely on acidic monomers capable of etching and interacting on a molecular level with tooth surfaces in order to form physical/chemical bonds between the restoration and the tooth. Whether Hagger's concept will become the norm in the future is still an open question, but one thing is certain: Hagger's idea is still very much alive," notes Söderholm. 14

Who: Per-Ingvar Brånemark
What: Discovery and application for osseointegration of dental implants
When: 1950s-1960s
Where: Gothenburg, Sweden
Purpose: The biological fusion of bone to a foreign material

Comments: In 1965, he placed the first Brånemark dental implant. This represented the first practical application of his discovery of osseointegration.

Evolution: Brånemark's discovery of osseointegration occurred in 1952. He and his team found that titanium oculars placed in the femurs of rabbits permanently attached to the bone after a period of healing. This discovery led him to develop and test a dental implant that used pure titanium screws (fixtures). 15 In 1982 in Toronto , Canada , Brånemark presented impressive and unparalled scientific documentation of osseointegration and implantology. His work—widely considered one of the most significant scientific breakthroughs in dentistry since the late 1970s—lead to widespread recognition of the Brånemark implant methods and materials. Currently, the Brånemark system of dental implants is available from Nobel Biocare. 15

Who: Robert J. Nelson
What: Water-turbine handpiece (Figure 15)
When: 1953
Where: National Bureau of Standards, Maryland
Purpose: Dental drill

Comments: Offered 60,000 rpm; by placing the turbine in the head of the drill, it eliminated gears within the handpiece

Evolution: See John Borden, Airotor entry

Who: Dr. Philippe-Guy Woog
What: Electric toothbrush
When: 1954
Where: Switzerland
Purpose: To improve oral hygiene and facilitate the process of brushing teeth

Comments: It changed the brushing habits of large sections of the population throughout the world and provided stimulation to and enhanced cleansing of oral tissues.

Evolution: The oscillating motor, electric toothbrush first appeared in 1956 in Switzerland and was introduced to the United States at the centennial celebration of the American Dental Association in 1959 by Squibb. In 1960, Squibb marketed the first American electrical toothbrush (Broxodent) in the United States. General Electric introduced a rechargeable cordless toothbrush in 1961. Introduced in 1987, Interplak was the first rotary action electrical toothbrush for home use. 2 Currently, there are more than 150 other brands of automatic toothbrushes that have been introduced since Woog's invention.16

Who: Michael Buonocore
What: The acid-etch technique
When: 1955
Where: Rochester, New York
Purpose: A simple method of increasing the adhesion of composite material to enamel

Comments: "His groundbreaking research laid the foundation for all modern cosmetic and esthetic dentistry," states Dr. Ring.

Evolution: When Buonocore proposed his technique, the field of dentistry eschewed the idea of placing acid on sound tooth structure because of the probability of oral tissue damage and cavities. More than a decade passed before the dental professional accepted the acid-etch technique as a safe and effective method of bonding resins and composites to enamel.

Who: John V. Borden
What: Airotor, a high-speed air-driven contra-angle handpiece (Figure 16)
When: 1957
Where: U.S. Naval Dental School, Bethesda, Maryland
Purpose: Dental drill

Comments: Operated by air, it allowed for rotational speeds of up to 300,000 rpm. Carbide burs and diamond drills complimented the new handpiece, and teeth could now be prepared much more quickly and with minimal vibration and pressure, marking a revolution in dental treatment. It has made possible better restorations with less sacrifice of tooth structure. It has made the patient more comfortable not only by reducing vibration but also by cutting working time to a fraction of what it was before. Additionally, it has allowed dentists to do finer and more complicated work unimagined only a few decades earlier.

Evolution: Since its introduction, many manufacturers have made modifications and improvements to the Borden drill. Fiber optics allow a light to shine directly on the bit; advances in ball bearings have brought speeds to above 350,000 rpm; some manufacturers have eliminated the ball bearings, letting the turbine ride on a cushion of compressed air; and the once-delicate handpieces are now manufactured to withstand high-pressure steam sterilization, notes Ring.17

Who: Rafael Bowen
What: Bis-GMA, the thermostat resin complex used in modern composite resin restorative materials
When: 1962
Where: National Bureau of Standards, Maryland
Purpose: Bowen's synthesis of this epoxy resin marked the first successful production of a composite resin for filling teeth since acrylic acid was discovered in 1843.

Comments: The earlier acrylic fillings of the 1940s had proved unsatisfactory because they discolored, shrank, contributed to pulpal inflammation, and allowed extensive decay to recur. Bowen's product demonstrated more stable properties and better cosmetic qualities. Since Bis-GMA could be made to resemble the color of natural teeth, it proved especially useful for fillings in anterior teeth.

Evolution: It has been estimated that dentists used Bis-GMA in at least 50 million restorations between 1962 and 1972, 18 and today it continues to be used in most modern composite resin restorative materials.

Who: Harald O. Heymann and V.B. Haywood
What: Home tooth-bleaching product
When: 1989
Where: University of North Carolina Dental School
Purpose: To whiten teeth

Comments: When Haywood and Heymann, two researchers at the University of North Carolina, published the first clinical study on tooth whitening, the study sparked a growth spurt for cosmetic dentistry and inspired the first home bleaching product, White and Brite.

Evolution: White and Brite was soon followed by a plethora of at-home tooth-whitening products that flooded the market. Some of these products had a very high acid content and were potentially harmful; others were not potent enough to be effective. To protect consumers from products like these, the Food and Drug Administration (FDA) and the American Dental Association (ADA) developed guidelines that required manufacturers to use scientific documentation to prove the safety and efficacy of their products. The media spotlight on tooth whitening, paired with extensive advertising campaigns, has fueled the growth of the typically static dental industry. The at-home tooth-whitening business has flourished into a $400 million industry, and awareness and demand for this esthetic procedure continues to soar to an all-time high. Today, 97% of dentists say that their patients ask them about bleaching their teeth. 19

Who: Zia Chishti
What: Invisalign braces
When: 1997
Where: United States
Purpose: Transparent, removable, and moldable braces to straighten teeth

Comments: Rather than a single pair of braces that are repeatedly adjusted, Invisalign braces, a series of clear aligners created by a computer, are worn in succession. Unlike regular braces, Invisalign braces can be easily removed for teeth cleaning, eating, and sports activities.

Evolution: Chishti and his business partner, Kelsey Wirth, founded Align Technology in 1997 to develop and manufacture the Invisalign braces. In May 2000, the Invisalign braces became available to the public for the first time. 20

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15. Available at: http://en.wikipedia.org/wiki/Per-Ingvar_Brånemark. Accessed March 16, 2009.

16. Available at: www.broxo.com/en/about_us/inventor.aspx. Accessed March 16, 2009.

17. Available at: www.americanheritage.com/articles/magazine/it/1995/2/1995_2_24.shtml. Accessed March 16, 2009.

18. Available at: www.nlm.nih.gov/hmd/pdf/american.pdf. Accessed March 16, 2009.

19. Available at: www.tightenandtone.com/teetharticles.htm. Accessed March 16, 2009.

20. Available at: http://inventors.about.com/od/dstartinventions/a/dentistry_4.htm. Accessed March 16, 2009.

Editorial Note: All photographs were provided courtesy of The Dr. Samuel D. Harris National Museum of Dentistry.

Figure 1 Antique toothbrushes. Figure 2 Dr. John Greenwood. Figure 3 A vignette of a dental office circa 1890. Figure 4 S.S. White porcelain teeth. Figure 5 A Snell chair label. Figure 6 A Wilkerson Dental Chair. Figure 8 Vulcanite. Figure 7 Robert Arthur. Figure 9 An old rubber dam. Figure 10 A Morrison foot-powered drill. Figure 11 Sheffield Dentifrice containers. Figure 12 The x-ray cathode. Figure 13 Replica of G.V. Black's dental office. Figure 15 A water-turbine handpiece. Figure 14 An antique can of Novocain. Figure 16 The Airotor handpiece.