Home Dentistry Articles Dental fillings
In the treatment of dental cavities, after
drilling out the cavities, dental fillings are inserted. The
intent is to prevent further damage to the tooth and thus avoid
the eventual need for the tooth to be extracted.
Amalgam fillings are an alloy of mercury (from
43% to 54%) along with silver, tin, and copper. Mercury-based
fillings were apparently first used by French dentists in the
1810s. They continue to be used today because of their hardness
and durability; and because they are cheap.
Mercury is toxic, and the use of amalgam fillings
is therefore controversial, as the fillings do emit mercury
as a minute amount of vapor. Various government agencies, including
the UN's World Health Organization and the USA's Food and Drug
Administration and Centers for Disease Control and Prevention
have stated that amalgam fillings are safe, even for pregnant
women, children, and diabetics, except in rare cases of allergy.
Composite resin fillings are a mixture of
powdered glass and plastic resin, and are white-colored. They
are considered strong and durable, and are closer to "normal"
tooth color than silver-colored amalgam fillings. They are much
Glass Ionomer Cement
These fillings are a mixture of glass and
an organic acid. They are tooth-colored and they vary in translucency.
They are usually used for small fillings, and are expensive
(about as expensive as composite resin). The fillings do not
wear as well as amalgam or composite resin fillings.
These fillings are a mixture of glass, an
organic acid, and resin polymer that harden when exposed to
a blue light that the dentist uses to finish the treatment.
(The light activates a catalyst in the cement that causes it
to cure in seconds.) The cost is similar to composite resin.
It holds up better than glass ionomer, but not as well as composite
resin, and is not recommended for biting surfaces of adults.
Porcelain fillings are hard, but can cause
wear on opposing teeth. They are brittle and are not usually
recommended for molar fillings.
Porcelain Fused to Metal
These are metal shells with porcelain "enameled"
on top, and is used for crowns. They are very durable.
Nickel or Cobalt-Chrome Alloys
These are mixtures of nickel and chromium
and are used for crowns and bridges. They can be abrasive to
opposing teeth and do conduct heat and cold, but have excellent
Gold fillings have excellent durability, wear
well, and do not cause excessive wear to the opposing teeth,
but they do conduct heat and cold, which can be irritating.
They are expensive.
Other historical fillings
Lead fillings were used in the 1700s, but
became unpopular in the 1800s because of their softness and
because lead poisoning was understood.
According to U.S. Civil War-era dental handbooks
from the mid-1800s, since the early 1800s metallic fillings
had been used, made of lead, gold, tin, platinum, silver, aluminum,
or amalgam. A pellet was rolled slightly larger than the cavity,
condensed into place with instruments, and then shaped and polished
in the patient's mouth. The filling was usually left "high",
with final condensation - "tamping down" - occurring
through the patient's chewing of food. Gold was the preferred
filling material during the Civil War, with amalgam being the
most common due to cost. Tin was also popular due to cost, but
was held in lower regard.
One survey  of dental practices in the mid-1800s
catalogued dental fillings found in the remains of seven Confederate
soldiers from the U.S. Civil War; they were made of:
Thorium - radioactivity was unknown at that
time, and the dentist probably thought he was working with tin
Lead and tungsten mixture, probably coming from shotgun pellets
Tin and iron
Three soldiers had gold fillings