|
As
required by Chapter 801, Statutes of 1992, the Dental Board of California
has prepared
this fact sheet to summarize information on the most frequently used
restorative dental
materials. Information on this fact sheet is intended to encourage
discussion between the
patient and dentist regarding the selection of dental materials best
suited for the patient's
dental needs. It is not intended to be a complete guide to dental
materials science.
The most frequently used materials in restorative dentistry are amalgam,
composite resin,
glass ionomer cement, resin-ionomer cement, porcelain (ceramic),
porcelain
(fused-to-metal), gold alloys (noble) and nickel or cobalt-chrome
(base-metal) alloys. Each
material has its own advantages and disadvantages, benefits and risks.
These and other
relevant factors are compared in the attached matrix titled
"Comparisons of Restorative
Dental Materials." A Glossary of Terms" is also attached to
assist the reader in
understanding the terms used.
The statements made are Supported by relevant, credible dental research
published mainly
between 1993 - 2001. In some cases, where contemporary research is sparse,
we have
indicated our best perceptions based upon information that predates 1993.
The reader should be aware that the outcome of dental treatment or
durability of a
restoration is not solely a function of the material from which the
restoration was made.
The durability of any restoration is influenced by the dentist's technique
when placing the
restoration, the ancillary materials used in the procedure, and the
patient's cooperation
during the procedure. Following restoration of the teeth, the longevity of
the restoration will
be strongly influenced by the patient's compliance with dental hygiene and
home care, their
diet and chewing habits.
Both the public and the dental profession are concerned about the safety
of dental
treatment and any potential health risks that might be associated with the
materials used to
restore the teeth. All materials commonly used (and listed in this fact
sheet) have been
shown -- through laboratory and clinical research,
as
well as through extensive clinical use --
to be safe and effective for the general population. The presence of these
materials in the
teeth does not cause adverse health problems for the majority of the
population. There
exist a diversity of various scientific opinions regarding the safety of
mercury dental
amalgams. The research literature in peer-reviewed scientific journals
suggests that
otherwise healthy women, children and diabetics are not at increased risk
for exposure to
mercury from dental amalgams. Although there are various opinions with
regard to mercury
risk in pregnancy, diabetes, and children, these opinions are not
scientifically conclusive and
therefore the dentist may want to discuss these opinions with their
patients. There is no
research evidence that suggests pregnant women, diabetics and children are
at increased
health risk from dental amalgam fillings in their mouth. A recent study
reported in the
JADA factors in a reduced tolerance (1/50th of the WHO safe limit) for
exposure in
calculating the amount of mercury that might be taken in from dental
fillings. This level falls
below the established safe limits for exposure to a low concentration of
mercury or any
other released component from a dental restorative material. Thus, while
these
sub-populations may be perceived to be at increased health risk from
exposure to dental
restorative materials, the scientific evidence does not support
that claim. However, there
are individuals who may be susceptible to sensitivity, allergic or adverse
reactions to
selected materials. As with all dental materials, the
risks and benefits should be discussed
with the patient, especially with those in susceptible populations.
There are
differences between dental materials and the individual elements or
components
that compose these materials. For example, dental amalgam filling material
is composed
mainly of mercury (43-54%) and varying percentages of silver, tin, and
copper (46-57%). It
should be noted that elemental mercury is listed on the Proposition 65
list of known toxins
and carcinogens. Like all materials in our environment, each of these
elements by themselves
is toxic at some level of concentration if they are taken into the body.
When they are mixed
together, they react chemically to form a crystalline metal alloy. Small
amounts of free
mercury may be released from amalgam fillings over time and can be
detected in bodily
fluids and expired air. The important question is whether any free mercury
is present in
sufficient levels to pose a health risk. Toxicity of any substance is
related to dose, and
doses of mercury or any other element that may be released from dental
amalgam fillings
falls far below the established safe levels as stated in the 1999 US
Health and Human
Service Toxicological Profile for Mercury Update.
All dental
restorative materials (as well as all materials that we come in contact
with in our
daily
life) have the potential to elicit allergic reactions in hypersensitive
individuals' 1 These
must be assessed on a case-by- case basis, and susceptible individuals
should avoid contact
with allergenic materials. Documented reports of allergic reactions to
dental amalgam exist
(usually manifested by transient skin rashes in individuals who have come
into contact with
the
material), but they are atypical. Documented reports of toxicity to dental
amalgam
exist, but they are rare. There have been anecdotal reports of toxicity to
dental amalgam
and as with all dental material risks and benefits of dental amalgam
should be discussed
with the patient, especially
with those in susceptible populations.
Composite
resins are the preferred alternative to amalgam in many cases. They have a
long
history of biocompatibility and safety. Composite resins are composed of a
variety of
complex inorganic and organic compounds, any of which might provoke
allergic response in
susceptible individuals. Reports of such sensitivity are atypical.
However, there are
individuals who may be susceptible to sensitivity, allergic or adverse
reactions to composite
resin restorations. The risks and benefits of all dental materials should
be discussed with
the patient, especially with those in susceptible populations.
Other dental
materials that have elicited significant concern among dentists are
nickel-chromium-beryllium alloys used predominantly for crowns and
bridges. Approximately
10% of the female population are alleged
to be allergic to nickel. The incidence of allergic
response to dental restorations made from nickel alloys is surprisingly
rare. However, when
a patient has a positive history of confirmed nickel allergy, or when such
hypersensitivity to
dental restorations is suspected, alternative metal alloys may be used.
Discussion with the
patient of the risks and benefits of these materials is indicated.
1 Dental Amalgam: A scientific review and recommended public health
service strategy for research, education and regulation, Dept. of Health
and Human Services, Public Health Service, January 1993.
2
Merck Index 1983, Tenth Edition, M Narsha Windhol z, (ed).
Glossary of Terms
General Description
Brief statement of the composition and behavior of the dental material.
Principal Uses
The types of dental restorations that are made from this material. Resistance to further
decay - The general ability of the material to prevent decay around it.
Longevity/Durability
The probable average length of time before the material will have to be replaced.
(This will depend upon many factors unrelated to the material such as biting habits of the
patient, their diet, the strength of their bite, oral hygiene, etc.)
Conservation of Tooth Structure
A general measure of how much tooth needs to be removed in order to place and retain the
material.
Surface Wear/Fracture Resistance
A general measure of how well the material holds up over time under the forces of biting,
grinding, clenching, etc.
Marginal Integrity
(Leakage) - An indication of the ability of the material to seal the interface between the
restoration and the tooth, thereby helping to prevent sensitivity and new decay.
Resistance to Occlusal Stress
The ability of the material to survive heavy biting forces over time.
Biocompatibility
The effect, if any, of the material on the general overall health of the patient.
Allergic or Adverse Reactions
Possible systemic or localized reactions of the skin, gums and other tissues to the material.
Toxicity
An indication of the ability of the material to interfere with normal physiologic processes
beyond the mouth.
Susceptibility to Sensitivity
An indication of the probability that the restored teeth may be sensitive of stimujli (heat,
cold, sweet, pressure) after the material is placed in them.
Esthetics
An indication of the degree to which the material resembles natural teeth.
Frequency of Repair or Replacement
An indication of the expected longevity of the restoration made from this material.
Relative Cost
A qualitative indication of what one would pay for a restoration made from this material
compared to all the rest.
Number of Visits Required
How many times a patient would usually have to go to the
dentist's office in order to get a restoration made from this material.
Dental Amalgam
Filling material which is composed mainly of mercury (43-54%) and varying percentages of
silver, tin, and copper (46-57%).
|
