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April 13, 2001 — The
health hazards posed by exposure to the metal beryllium were once
mainly
associated with workers in the nuclear, electronics, and
aircraft industries. However, the element may also pose risks
to dental technicians who handle dental crowns and bridges composed
of beryllium—nickel alloys.
Dental laboratory technicians must often grind, finish,
and machine beryllium—containing metals, producing small
beryllium dust particles that can lodge in the lungs. We now know
that workplace
exposure to beryllium can lead to chronic
beryllium disease, a painful scarring of the lung tissue.
Considered carcinogenic, beryllium may also cause lung cancer,
skin rashes, and other ailments.
Although the potential problems of beryllium exposure in the dental
industry were known for many years, it was not until 1993 that
a case of chronic beryllium disease in a dental laboratory technician
was documented in a scientific journal (Kotloff, R.M.,
P.S. Richman et al., (1993) Am Rev Respir Dis 147(1) 205—7).The
researchers suspected that the technician had chronic beryllium
disease based on clinical, radiographic and histological studies.
They confirmed the diagnosis by using a beryllium
lymphocyte proliferation test, known as BeLPT.
Recently, a medical researcher spoke out about another case
of chronic beryllium disease in a dental laboratory technician
(Dr.
Lee Newman, Head, Division of Environmental and Occupational
Health Sciences, National Jewish Medical and Research Center,
letter
dated January 30, 2001). The technician had sandblasted
metal alloys containing beryllium; cut the metal pieces with
a high—speed
lathe; and removed the bubbles with a handheld electric grinder
and burr. She performed this work repeatedly over a period of
eight
years while wearing only a paper dust mask.
Use of metal alloys at dental laboratories

In a survey of 51 dental laboratories in the Cleveland, Ohio
area, 11 laboratories indicated that they used beryllium alloys,
27 said that they did not, and 13 refused to respond (Ohio
Citizen Action Survey, February 21, 2001). An informal
study by the same group showed that many dental suppliers did not
provide the laboratories with adequate information about beryllium
health hazards in their Material Safety Data Sheets, forms
required by the Occupational Safety and Health Administration
or OSHA (Ohio
Citizen Action, letter dated February 21, 2001).
This study, although limited in scope, illustrates the
need for better monitoring of the dental industry. Because of the
serious health problems associated with beryllium, it is
important that dental laboratory workers be correctly informed
about the hazards
of beryllium dust and fumes. Safety precautions such as the use
of respirators and advanced ventilation systems are necessary
not
only in large manufacturing companies, but also in the dental
laboratory.
What are the risks for patients?

The story of beryllium and the dental industry would not be complete
without looking at how beryllium—containing alloys may affect
dental patients. A preliminary study describes two patients who
developed
gingivitis (gum disease) adjacent to a beryllium—containing
alloy in dental prostheses (Kuang, B. and P. A. Rubenstein
(1993); Contact Dermatitis 28(3): 157—62; revised in Contact
Dermatitis 29(4):222). Patch testing showed positive reactions
to beryllium
sulfate, a component of the alloy. In another study, some
patients exhibited allergic reactions to nickel, beryllium,
copper and other metals in dental prostheses (Vilaplana, J.,
C. Romaguera, et al. (1994); Contact Dermatitis 30(2):80—4).
More work needs to be done to determine if beryllium—containing
alloys are problematic to dental patients. We know very little
about
how or if these alloys may affect patients over long periods of
time. Meanwhile, wisdom dictates that dentists consider using
dental crowns and bridges that do not contain beryllium.
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