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What
is the best material?
Quite often we are asked what material is best to restore a
tooth. This question could have differing answers which somewhat
hinge on the desires of the individual being treated. The
following will help you see why.
If
you were to ask a group of top dentists what is the best overall
restorative material/technique, they would agree hands down that
well done gold restorations would be the best choice. You
would also find that they would have gold restorations in their
mouths.
Why
gold?
Gold inlays (gold restorations placed inside the tooth),
onlays (gold restorations placed inside the tooth and also
covering weakened areas of the biting surface), crowns (complete
coverage of the tooth) & partial crowns performed with high
skill and care are definitely the best for strength, accuracy of
fit, finishing, and because of cast gold's strength, it allows the
opportunity to be made thin and therefore be conservative with more
remaining tooth structure left than occurs with other types of crown
restorations. In the February, 1995 edition of the American
Dental Association Journal, Gordon J. Christensen, DDS, MSD, PhD
states:
“Some
dentists have avoided inlays and onlays because they require somewhat
more time and expertise during tooth preparation and seating than
full crowns. In spite of these obvious differences, isn’t
it unfortunate that third-party fee schedules often pay less for
inlays and onlays than for crowns? Insurance companies and
patients should pay more for conservative restorations than for
full crowns. Clinical procedures for cast gold inlays and
onlays are more difficult than full crowns”.
Conservative,
less traumatic approach.
Most often, cast gold restorations are done on a tooth that has
already had decay(s) and filled with a silver/mercury filling which
is breaking down. Teeth which have been filled previously have pulps
(nerves) which have already been traumatized from the original decay
and the dentist grinding to fill it. This type of tooth need
not be ground away a lot in order to be restored with cast gold
- very little trauma to the pulp. The thing that cast gold
restorations allows is that when they are well done, they offer
the best chance of that tooth not needing to be restored again and
not needing a root canal.
As
wonderful a restorative material as it is, as mentioned above by
Dr. Christensen, its utilization needs to be accompanied by a high
degree of skill. This is the reason that Dr. McBride has been
involved with the Cast Gold Study Club at U.C.L.A.
Appearance
versus practicality.
Persons vary in their degree of discrimination relative to the
display of gold desired in their mouths. Most often gold restorations
are placed in the back of the mouth, and can be made relatively
inconspicuous. Some persons want to have no possibility of
any visible gold however, so it is fortunate that there are some
good esthetic alternatives. Some of the newer porcelain and
composite materials are very good esthetically. The full porcelain
crown has been around for quite some time, and it is a very fine,
esthetic restoration for a tooth which is already quite broken down.
It is a restoration that requires the most removal of tooth structure
as compared to any other type of restoration, to make room for the
core under-support material plus the varying layers of porcelain
which make it appear like a tooth in both color and shape.
By definition, preparing teeth for these restorations subjects the
dental nerve tissue to more trauma than any other type of restoration.
Ask any root canal specialist which type of tooth that they most
frequently treat, and they will definitely say those with porcelain
crowns.
A
newer material is now available called Complete Porcelain. This
was revolutionary to persons with high esthetic expectations because
it provides translucency much like natural tooth enamel and can
be made without metals to gray the gumline. Ask Dr. McBride
about this material, it may be right for you.
Tooth
colored, laboratory processed inlays and onlays.
If a tooth is not broken down enough for a full porcelain crown,
but is in an area where even a conservative gold casting would not
be desired esthetically, conservative porcelain and laboratory processed
composite inlays can be used to restore back teeth. As esthetic
as they are however, when compared to gold, the "fit"
cannot be made as tight and the resin which is used to bond them
to the tooth does wash away over time.
Tooth
colored bonded fillings.
Bonding composite material which is placed directly into back
teeth in one office appointment
tends to wear away over time, especially largely filled areas, because
of the great pressures exerted on them during chewing. The
smaller the filling, the less wearing away. Therefore this
type of material works best very small areas in back teeth and in
front teeth where there is no heavy chewing pressure, and is the
material which is commonly known as "bonding".
What
about silver-mercury fillings?
We are also asked whether or not silver/mercury amalgam fillings
are harmful, due to the fact that mercury does continue to "leak"
from them. Studies show that the amount is less than the amount
of mercury found in some seafood. It is agreed that some persons
may be hypersensitive or allergic to mercury, but it is a very rare
event.
The
thing that I see over and over with silver/mercury fillings, especially
large ones, are fractures in the tooth structure around them. Almost
all teeth that break have amalgam fillings in them. Studies show
that the filling material expands within the tooth after placement
(like the mercury in a thermometer). I believe that it continues
to expand or expands at a significantly different rate than tooth
structure, therefore stressing the tooth until it fractures. Anaylsis
of tooth preparation design for amalgam fillings shows that
there are damaging biomechanical forces placed on the teeth because
of a “wedging” effect. Quite often, we see a tooth with the
silver-mercury filling still in it with up to ¾’s of the tooth structure
gone around it.
Excellent
communication the key.
So, it can be seen that it is quite often an individual
matter as to which type of restorative material is best – based
upon what is best for the particular tooth, teeth or mouth, and
influenced by the esthetic concerns of the patient. The important
thing is that there is excellent communication between patient and
dentist so that the needs and concerns of the patient are addressed,
and at the same time, a quality treatment plan developed based upon
the skill, care and judgment of the dentist.
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