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Dr Wolley is an expert on bio-compatible materials. Many of the materials used in his practice are manufactured in Germany and Switzerland.

Glass ionomers were introduced to the dental profession in the 1970s. Originally, their acceptance by the dental community was limited because of problems associated with manipulation of the material, setting sequence, moisture sensitivity, less than expected esthetic value and surface texture.

Recently, dentists are increasing their use of glass ionomer because of the following characteristics:

the material chemically bonds to the tooth structure and releases fluoride
the placement technique is conservative, requires minimal drilling and the patient response is excellent
the procedure is often quick, painless, and may not require local anesthesia
the restoration is fairly esthetic

Recently, dentists are increasing their use of glass ionomer because of the following characteristics ....the material chemically bonds to the tooth structure and releases FLUORIDE!!!

"The practice of dentistry and the National Institute of Standards and Technology (NIST) go back a long way--back to 1919 in fact, when the U.S. Army asked NIST, then the National Bureau of Standards, to look into the physical factors behind good and bad metal-based amalgams for filling teeth. Ten years later, NIST's laboratory predecessor began what continues to be a collaboration with the American Dental Association whose goal has been the development, refinement and general improvement of medical practice through the invention of new dental materials, tools and methods."

TN-5948

GOVERNMENT/INDUSTRY COLLABORATE TO DEVELOP MERCURY-FREE DENTAL MATERIAL

A mercury-free, direct filling alternative for conventional
dental amalgams is being developed at the National Institute of
Standards and Technology. The new restorative process uses
metallic powders in a form that is easily applied to prepared
tooth cavities by dentists using treatment procedures very
similar to those in current practice.

     The dental material project is a collaborative effort
between government and industry. The National Institute of
Dental Research is contributing support for the program through
the American Dental Association Health Foundation's Center for
Excellence. The ADAHF maintains the Paffenbarger Research Center
at NIST.

     A dental materials manufacturer, Dentsply International,
Milford, Del., has a cooperative research and development
agreement with NIST to help develop the new mercury-free
restorative material.

     The new restorative process is based on NIST electrochemical
powder technology. The technique was invented by David S.
Lashmore, leader of the NIST Electrodeposition Group, and Moshe
P. Dariel, guest scientist from the David Ben-Gurion University,
Beer-Sheva, Israel.

     "The mercury-free dental material project offers us an
opportunity to transfer technology developed at NIST to industry
and meet a national need," said Lashmore.

     He points out that the mercury content of amalgams used in
the overwhelming majority of dental restoratives continues to
raise concern with regard to their long-term effect on public
health and the environment. The new alloy will help reduce the
amount of mercury dispersed in the environment by dental waste.

     Joyce Reese, NIDR program director for Biomaterials, Pulp
Biology and Dental Implants, notes that although there is no
scientific evidence linking mercury in amalgam to systemic
diseases, the new NIST mercury-free, dental restorative material
meets an important objective of the National Institute of Dental
Research to find alternative materials for conventional dental
amalgams.

     Lashmore said that the principal goal of the NIST research
has been to develop a high-performance, mercury-free alloy that
will consolidate at body temperature in prepared tooth cavities.

     The material involves the use of biocompatible metallic
powders such as silver-coated tin. These pairs of metals undergo
fast diffusion or combine to form an in-situ intermetallic
compound at body temperature.

     The treatment of tooth cavities is quite simple. The dental
practitioner will mix the coated powders with an activating,
biocompatible liquid to form a slurry. The mixture is then
pressed into a prepared filling with conventional dental
instruments. After compaction, the material hardens into a
strong, mercury-free dental alloy.

     Lashmore explains that even though silver and tin are the
principal ingredients, investigations are being conducted with
other formulations that may contain copper, gold, or small
amounts of other inert materials such as silver, alumina and
silicon carbide. He emphasizes that all of the materials under
study are free from mercury, indium or gallium, which are
commonly used today in dental amalgams.

     According to Lashmore, the new direct filling restorative
material could be in dental offices within three years. It will
be tested both at NIST and by independent dental research
laboratories before undergoing review by the Food and Drug
Administration.

     As a non-regulatory agency of the Commerce Department's
Technology Administration, NIST promotes U.S. ecomnomic growth by
working with industry to develop and apply technology,
measurements and standards.

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NOTE TO EDITORS: NIST, which was established in 1901 as the
National Bureau of Standards, has a materials research program
that is recognized worldwide. As a non-regulatory agency, NIST
is conducting research on dental materials to support the safe,
efficient and economical use of materials for the benefit of
consumers and the practicing dental professional.

The NIST dental materials program is a long-standing model
of cooperation between the private sector and government.
Researchers from the dental profession, industry and government
have worked together at NIST for more than 65 years to improve
dental materials and devices.

NIDR, one of the National Institutes of Health, Bethesda,
Md., is the primary sponsor of dental research and related
training in the United States.