No one doubts that the past century gave rise to major advances in dentistry.
To evoke the triumphs of the recent past, experts in various areas have
provided a retrospective glance and in some cases, personal reminiscences
that take us back to the future, a time not so very
far away that set the stage for the dental technologies we now take for
Dr. Gustavo Cruz
At the dawn of the twentieth century, the dentists armamentarium
for treating dental caries consisted basically of one approach: tooth
extraction. Effective caries prevention techniques were nonexistent and,
not surprisingly, dental decay was rampant in the United States and in
most Western nations.
Then, in 1945, Dr. H. Trendley Dean, the first director of the National
Institute for Dental Research, now the National Institute for Dental and
Craniofacial Research (NIDCR), introduced the concept of water fluoridation.
Since that time, water fluoridation and the widespread use of fluoride-containing
dentifrices have radically reduced the prevalence and severity of dental
caries especially among children. Cities in the United States first
started fluoridating their water in 1945. Today over 62 percent of the
population, and approximately 300 million people worldwide, drink fluoridated
water. In recent years, the benefits of fluoridation have been expanded
further through the use of fluoride-containing mouthrinses, supplements
and tablets, topically-applied gels, varnishes, and other products such
as fluoride-releasing restorative materials. Importantly, the benefits
are shared by both children and adults and continue over a lifetime if
Fluoridation is the least expensive, most fundamental, and most socially
equitable method for reducing tooth decay, tooth loss, pain and suffering,
and subsequent absences from school and work. Thanks to the benefits of
fluoridation, tooth loss is no longer considered inevitable, more and
more adults are retaining their teeth throughout life, and the quality
of life has improved for many Americans. Indeed, the Centers for Disease
Control (CDC) recently cited water fluoridation as one of the great public
health achievements of the past 100 years.
Yet despite these strides, dental caries continues to afflict more than
90 percent of the U.S. population and its distribution is uneven, resulting
in profound oral health disparities. The profession has it within its
power to address this problem using fluoride and other methods of caries
prevention to virtually eliminate dental caries in children and to significantly
control the disease in adults. Most of these methods have in common the
use of various forms of fluoride delivery. Thanks to this expanded array
of caries-prevention methods, the emphasis has shifted from the restoration
and repair of damaged hard tissues to the control, remineralization, and
regeneration of lost tissues.
By 2010, the first wave of baby boomers will reach age 65, making this
the first generation to reach that age with relatively intact dentition.
As a result, more teeth will be at continued risk for dental caries and
dentists will be called on in greater numbers than ever before to utilize
fluoride in its many delivery forms.
Dr. Cruz is Director of Public Health and Health Promotion and an assistant
professor of epidemiology and health promotion.
Dr. Saul Bahn
In the 1900s, the majority of dentists embraced the professions
ability to block transmission of peripheral pain and reduce patient distress
using a variety of local anesthetics.
Drs. Drummond-Jackson, Hubbell, Jorgensen, Wyckoff, Bullard, Davidau,
ONeil, Verrill and others promoted intravenous anesthesia for ambulatory
dental patients using a variety of agents that have proven to be effective
and relatively safe anxiolytics, including opioids, barbiturates, benzodiazepines,
and propofol. However, patient management problems sometimes occurred.
From the 1940s through the 1970s, Drs. Harry Seldin and Harry Langer encouraged
dentists to utilize inhalation conscious sedation and developed quality
courses and textbooks on relative analgesia.
Todays dentists and physicians have further refined anesthesias
ability to control fear, anxiety, and pain, and to perform invasive procedures
without significant patient distress. Moreover, improved monitoring of
patient status now utilizes self-activating or continuous vital sign monitors,
pulse oximetry, end-tidal carbon dioxide
monitors, and bispectral analysis.
The future is even more promising. Based on discoveries of the genetic
and hormonal implications of drug receptor activities, there is growing
belief among scientists that analgesia, sedation, and general anesthesia
can be precision-tailored for each individual. Bispectral analysis of
the level of sedation, using modified electroencephalography, can help
to individualize each patients depth of consciousness and further
enhance safety and efficacy. As it has done for the past century, anesthesia
continues to light up the darkness.
Dr. Bahn is a professor of oral and maxillofacial surgery and Director
of the Pain and Anxiety Control Program.
Dr. John R. Calamia
By 1925, basically three types of cement were used in dentistry to mechanically
attach orthodontic appliances, ceramic and metal inlays, posts, crowns
and bridges to tooth structure. They were silicate cement, zinc phosphate
cement, and zinc oxide eugenol cement. Also used as bases or liners under
metal restorations, these materials did not bond to the restoration or
to the tooth structure. The situation remained essentially unchanged until
1963, when a British researcher developed zinc polycarboxylate cements,
which were set by a reaction between metal oxides and water soluble polymers.
This advance was followed in the 1970s by the introduction of glass ionomers,
which created the first chemical bonds to tooth enamel and dentin. However,
the bond remained fairly weak despite attempts at preconditioning the
tooth surfaces with acids.
A major turning point in restorative dentistry occurred in 1955, when
Michael Buonocore introduced the acid etch technique. This innovation,
which created a physical seal at the tooth enamel-restoration interface,
along with the development of composite resins by Rafael Bowen, made possible
the longterm adhesion of tooth-colored materials to the enamel tooth structure,
and fostered the rapid development of clinical techniques such as pit
and fissure sealants, bonded composite restorations, and modern cosmetic
The next major breakthroughs came with the mechanical and chemical bonding
of dental materials to tooth structure, such as electrolytic etching of
non-precious alloys (Thompson and Liveditis), and etching and
silanation of porcelain (Calamia and Simonsen). These innovations introduced
a new generation of bonded restorations held to the enamel of teeth with
resin cements. The former led to the placement of bonded bridgework with
little preparation (reduction) of otherwise healthy abutment teeth. The
latter allowed for a predictable repair of porcelain surfaces as well
as a veneering technique which has revolutionized cosmetic dentistry.
Subsequently, resin cements were refined to the point that they were able
to bond to metals without electrolytic etching (C&B Metabond and Panavia).
This also allowed for the direct placement of orthodontic brackets without
the need for unsightly bands. The etched porcelain techniques could be
applied to posterior restorations if only good bonds to dentin could be
In the last quarter of the 20th century, acceptable bonds to dentin finally
became a reality and dramatically boosted the popularity of cosmetic dental
services. Products of the mid-1960s, like Cervident, produced microleakage
at the restoration/dentin interface. The second generation materials of
the early 1980s used primarily polymerizable phosphates added to Bis-GMA
(hydrophobic resins). These bonds, though improved, were still very weak
and clinically unsuccessful. A third generation of materials, developed
in the mid-1980s, utilized a combination of hydrophylic resins and conditioners
that removed the smear layer and showed much better bond strengths.
The latest generations of dentin bonding materials have enabled the successful
bonding of ceramic and ceromer (ceramic optimized polymer) inlays and
onlays, crowns, posts, and bridges, as well as successfully bonded amalgam
restorations and posterior direct addition composites of both the traditional
and condensable types. These advances have increased the speed, efficiency,
and longterm placement prospects of bonded restorations to both enamel
and dentin. In so doing, they have set new parameters for the practice
of restorative dentistry and have paved the way for even more revolutionary
advances in the century now unfolding.
Dr. Calamia is a professor of cariology and operative dentistry and Director
of Aesthetics and High Technology.
Mr. George Rhodes
During the mid-1950s, an air-powered turbine-operated dental handpiece
patented by Dr. John Borden of Washington, D.C., transformed the practice
of dentistry for both practitioners and patients. "People dreaded
dentistry because it was a horrible experience from a sound and vibration
standpoint. It was medieval," said Dr. Borden years later.
Dr. Borden knew that more speed was the key to improving on the standard
pulley-driven dental drill of the time. However, when increased speeds
were used, pulley drills burned the patients cheek. Dr. Bordens
innovation involved using air rather than pulleys to spin a drill bit
or other tools in the dental handpiece. But his ideas were way ahead of
the technology of his time: ball bearings, a key component of the handpiece,
were not small enough or would disintegrate under the intense speed generated
by the unit. Still, Dr. Borden persevered in his quest for a better dental
By 1954, Dr. Borden had 10 different design concepts, many turbine variations,
and repeated ball bearing failures. In 1956, however, he perfected one
design with the help of a machinist. Dr. Borden resolved the ball bearing
problem by using small, low-speed ball bearings. These were more durable
than the high-speed version, which disintegrated within two minutes. He
also reduced friction by pushing air between the balls, making 16 ball
bearings float in a quarter inch of space.
Whereas conventional drills of the time and earlier rotated the tools
used in them primarily burs for drilling out cavities at
a maximum speed of 6,000 rpm, Dr. Bordens air-powered handpiece,
known as the Borden Airotor, could rotate tools at speeds of 250,000 rpm,
over 40 times faster than conventional, pulley-driven drills.
The Borden Airotor reduced by 90 percent the time dentists required to
repair cavities for fillings, make crown preparations, and perform other
functions. A cavity preparation that could take as long as 20 minutes
with the old handpiece could now be completed in a minute or two. Patients
especially benefited from less time consuming, noisy, and painful procedures.
As a result, they were motivated to make more visits to the dentist, the
amount of dentistry being done became more productive, and dentists
One year after Dr. Borden introduced his air-powered handpiece at the
1956 District Dental Society Meeting in Washington, D.C., DENTSPLY, then
known as The Dentists Supply Company of New York, negotiated an
exclusive agreement for its manufacture and distribution. The end result
was a revolutionary dental tool now used in virtually every dental office
around the world.
Mr. Rhodes is vice president for corporate communications for DENTSPLY
Dr. James Kaim
The development of composite resins (cements, direct and indirect intra-coronal
materials, dentin bonding systems, crowns), making it possible to bond
a filling to tooth structure, has had a revolutionary impact on the practice
of dentistry. Consider the following: The concept of extension for prevention,
the classic G.V. Black preparation, has been replaced with a dramatically
more conservative contemporary preparation. The philosophy
of the more you cut a tooth, the more you weaken a tooth, has led to the
teaching of minimally invasive procedures. The ability to bond and seal
restorative tooth interfaces has provided the potential for more caries-resistant
margins. Recent refinements in the type and percentage of fillers have
created flowable and packable materials. Incorporation of adjunct materials
in particular polyacid modified resins has led to the development
of Componers, or low-fluoride releasing composites. Componers
not only have the potential to improve the margins of a restoration but,
in addition, the fluoride release potentiates the caries-resistant properties.The
success of the original formulation of composite resins can be traced
to research done in the 1950s by Dr. Michael Buonocore. Dr. Buonocores
work in the area now known as etching enabled dentists to
bond and seal the margins of restorations. By the time of the amalgam
scare of the 1970s, consumers were demanding not only less controversial
treatment options but also more aesthetic ones, and the popularity of
composite resins soared.
Composite resins permit dentists to cultivate and utilize their skills
not only as surgeons but also as artists. And continually improving composite
resin systems permit dentists to perform relatively low-cost, aesthetic
dental makeovers in as little as 45 minutes. By profoundly changing physical
appearance, resins thus have impacted not only the dental health but also
the mental health and self esteem of many patients.
With dentistry headed
more and more in the direction of prevention and remineralization, composite
resins will be the single substance used to treat the next generation
of patients throughout their lives, from infants and children requiring
preventive procedures to a growing geriatric population with special needs.
Even surgical intervention, when required, will take place with improved
Dr. Kaim, Class of 1970, is a professor and the chairman of the Department
of Cariology and Operative Dentistry.
Dr. Dennis P. Tarnow
Today, if a patient loses a tooth, the adjacent teeth do not have to be
prepared to support a fixed bridge. A single implant can be placed instead.
This saves healthy teeth from ever having to be crowned, which is especially
fortunate since the success rate of a single implant is better than that
of a three-unit bridge. The reason for this success is that a crown on
an implant cannot decay; its all metal to metal. This means that
patients who have a high decay rate can be treated without fear of problems
developing under the crowns.
But just as implants have dramatically transformed dental practice, so
too have they been transformed from an unpredictable technique when introduced
at the beginning of the last century to one of the most scientifically
predictable and clinically documented treatment modalities.
In the early 1900s, implant pioneers experimented with various metals
to identify one that would be accepted by the alveolar bone in order to
support artificial crowns after a tooth was extracted. Most of these attempts
were unsuccessful and occasionally caused additional problems for the
patient. In the 1940s and 1950s, the subperiosteal implant which
rests on bone rather than going into it was introduced. Over the
years, this implant proved fairly successful in supporting bridges, especially
on severely atrophied mandibles.
The 1960s brought new shapes and designs of implants that could be placed
into the bone successfully. However, many of these new implants lasted
only five-to-10 years before having to be replaced. Then, in the 1970s,
the concept of osseointegration of implants to bone took hold. For the
first time, the profession could offer predictable, implant-supported
restorations for full arch cases. As a bonus, implants were shown to stop
the loss of alveolar bone resorption that occurs after years of denture
In the 1980s and 1990s, the predictability of full arch cases was extended
to include partially edentulous jaws, even those involving single tooth
replacement situations. Today there is a 95 percent success rate for most
implants. In fact, implants have become so safe and predictable that practitioners
who in the past were concerned exclusively with getting the implants to
function are more concerned today about the aesthetics surrounding the
implants. Does the buccal height of tissue look normal, and are the papillae
reformed adjacent to the implant?
Another indication of how far implants have come is that patients today
can be treated with great predictability even if they are prone to periodontal
disease or decay since certain types of machined and polished coatings,
when placed near the top of implants, make them extremely resistant to
peri-implantitis. Now thats a transformation!
Dr. Tarnow, Class of 1972, is a professor and the chairman of the Ashman
Department of Implant Dentistry.