Dental Materials Analysis:
General Facts, Advantages, Disadvantages
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Composite fillings are less durable
than amalgam if the filling is large, but comparable in
durability if the filling is small to average size. |
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Composite fillings in back teeth are
significantly more difficult and time-consuming to place
than amalgam fillings, therefore more expensive. However,
they are more natural-looking, require less tooth
reduction to place, and are bonded in place for a better
seal. |
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Composites are not totally compatible
either. Most are made of the petro-chemical bis-phenol,
which some research indicates leeches out estrogen-like
substances. |
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Some composites are less biocompatible
than others because of the amount of iron oxide, aluminum
oxide, barium, and other unique materials in them. I most
often use Conquest Crystal, a polycarbonate-dimethacrylate resin with a barium boron
silicate filler. |
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Direct composites can cause hairline
cracks in the tooth from the hardening process, whereas
indirect composites do not because they are hardened in
the lab. |
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Porcelain is more natural-looking than
composites, but because it is harder and more brittle, it
causes a wearing away of everything it comes into contact
with and can crack instead of flex from high stress. |
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All porcelains contain aluminum oxide.
The one exception is unshaded Dicor,
which is weaker and not very natural-looking (over a
period of 3-4 months, unshaded dicor will pick up the
shade of the tooth under it). |
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If metal is not used in a crown or
bridge, it is significantly weaker and has an increased
risk of breakage during normal function. |
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Gold fillings, porcelain fillings,
indirect composite fillings, and crowns require more
tooth structure to be trimmed away than for amalgam and
direct composites, and take 2 appointments rather than 1. |
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Most "gold" crowns placed
today contain from 1% - 40% gold and have nickel in them
which is inappropriate for those with a compromised
immune system. Special order higher content gold will
obviously cost more due to the cost of gold. I most often
use Sterngold, E2713. |
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Studies of gallium alloys have
reported problems with corrosion, durability, tooth
fracture, and tooth sensitivity. More research and
development is needed, but for now, it is recommended for
use in baby teeth only. |
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Some experts consider all metals, even
non-allergenic or non-toxic metals, to be disruptive and
therefore should never be used in the body. Since nearly
all composites and porcelains contain iron and aluminum
oxides, some experts limit their choice of materials to
only a few. Still other experts think the use of high
quality metals like high content gold or titanium is
acceptable, but only if one brand and
formulation is used for the entire mouth. One must always
weigh biocompatibility against function and durability. |
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Because of contractual language and
statistics, use of titanium, high content gold, and
composite for crowns, bridges, or fillings will probably
result in lessened insurance benefits, even though
the time, cost, and effort in doing them is the same or
more as for standard gold alloy and porcelain materials. |
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Cadmium is used for color
stabilization, so cadmium-free materials may lose some of
it color over time. |
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I do not use amalgam (mercury),
non-precious metals (nickel, cobalt, chromium,
beryllium), or galloy in my practice. |
Many thanks to Ron King,
DDS, Minneapolis, MN
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