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When most people think of a "filling", they imagine
an item made out of some sort of material, either metal or plastic that is
placed directly in a hole in a tooth, carved to resemble the original shape of
the tooth, and then allowed to harden inside the hole to restore the form and
function of the tooth. Of course, it also must relieve the pain associated with
the cavity. In fact, these "direct" restorations, though far
and away the most common types due to their lower cost are only one half of the
equation. |
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Another type of restoration, less common due to their much higher
cost, are called "indirect" restorations. These "fillings"
justify their expense by being more durable (in other words, properly cared for,
they should last longer than regular indirect restorations), and also more
esthetic (better looking because they are actually built by a laboratory
technician on a lab bench without the difficulties imposed by the time
constraint and the poor access the dentist faces working in a patient's mouth).
Indirect fillings, made in a dental laboratory, are known as inlays and onlays.
Indirect fillings used to be more common when gold and ivory were the principal
dental materials. With the advent of porcelain laboratory produced
restorations, most dentists today prefer the superior strength and esthetics of
"full coverage" of the tooth in the form of
crowns
or veneers rather than simply filling cavities
with laboratory processed gold or porcelain fillings. For a side by
side comparison of the characteristics of all indirect filling materials please
see my reproduction of the American Dental Association
Table
of indirect restorative dental materials.
|
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root canals cause other systemic diseases such as arthritis, fibromyalgia,
scleroderma, multiple sclerosis, lupus, Chronic fatigue or various
autoimmune diseases?
Click
here
to find out |
The types of fillings
There are three major types of direct filling materials
(direct fillings are placed in a prepared hole in a tooth, carved or molded to
look like a tooth, and then light cured or allowed to harden;
- silver amalgam, made of a mixture of an alloy of
silver-tin and liquid mercury
- composite (combination of glass/porcelain particles in a plastic matrix)
- temporary filling materials
There are also three major types of indirect
filling material;
- gold (and other semi precious metals)
- fused porcelain
- composite (There is an
indirect form of composite which some dentists use.)
For a side by side comparison of the characteristics of all
non temporary direct dental materials, please see my reproduction of the
American Dental Association
Table
of direct restorative Dental Materials.
|
 Meth
mouth
What happens to your teeth when you are a serious addict? |
Silver Amalgam and the
"mercury issue"--Are my fillings killing me??
Silver Amalgam is the most commonly used material in the restoration of
decayed teeth in the world! It was invented in France in the early 1800's
and introduced into the US by two french enterpreneurs, the Crawcour brothers.
Due to its mercury content, it was denounced by a majority of the dental
profession since mercury was known to be a poisonous material. What was
not fully recognized at the time was that elemental mercury, especially
when bound into a solid amalgam with other metals is not well
absorbed into the human body. The belief in the severity of the toxicity of
mercury was based upon the toxicity of soluble mercury salts and organic mercury
compounds which had been used industrially in the manufacture of the felt
used to make hats. Even though the dental profession of the day denounced the
use of amalgam for the repair of the teeth, the brothers went on to repair huge
number of mouths with it. In spite of appalling dentistry (they seldom
removed the bulk of decay and violated every principle of dentistry known even
at that time), they were not only successful entrepreneurs, but the teeth they
repaired mostly remained successfully repaired for many years! Often,
these restorations seemed to work better than the expensive gold restorations
placed by the "expensive dentists". Furthermore, the predictions of
widespread mercury poisoning proved to be false. Prior to the introduction of amalgam, the only materials available to repair
decayed back teeth were tin foil, lead plugs and gold leaf. Tin has a
nasty habit of falling out of the cavity preparation, Lead was known to be
poisonous, and gold leaf was very time consuming and so expensive that only the
very wealthy could afford it. Cast gold did not become available until
1910. On the other hand,
dental amalgam was not especially technique sensitive and it required much less
time (and consequently less pain) to prepare the teeth. The amalgam itself is quite inexpensive, and
after the introduction of
Coca Cola in 1886, the
demand for affordable dentistry skyrocketed. Even in those days, Americans
realized that the average Joe was being discriminated against because of the
lack of choice in dentistry, and dentists were forced to reevaluate the use of amalgam.
They discovered (to their consternation) that NO ONE who had their teeth filled with amalgam suffered from
any of the symptoms associated with mercury poisoning. Many dentists still
refused to use amalgam, and they formed the core of the burgeoning anti-amalgamist
movement. They were very angry, since a bunch of newcomers to the
profession were taking away their core business. Unfortunately, since no
one was exhibiting the symptoms of mercury poisoning, the anti-amalgamists had
to rely on scaring the public with horror stories about diseases like diabetes,
arthritis, gout, etc. for which the medical profession had no explanation.
Unfortunately for the anti-amalgamists, the list of diseases that dental amalgam
supposedly caused kept shrinking as the real causes of these diseases was
discovered by researchers. Today we know that there is no known
statistical difference in the health status of persons with amalgam fillings
compared to those with no fillings in their teeth!
Please refer to the following links:
The
Multiple Sclerosis Society's statement on dental amalgam: The
American
Dental Association's statement on dental amalgam: The
Department of
Health and Human Services (HHS) statement on dental amalgam: also
The US Public Health
Service website on the safety of dental amalgam
 In
the meantime, the rest of the dental profession had moved on and accepted dental
amalgam as one of the major armaments in the fight against decay. A
dentist named G.V. Black (1836-1915- pictured to the right) finally laid the
foundation for the correct use of the new material and essentially
revolutionized the profession of dentistry by standardizing the repair of teeth
and making dentistry affordable to everyone.
Today, silver amalgam is still the most popular tooth filling material in the
world. It has been used extensively worldwide for nearly 200 years, and
almost everyone in the industrialized world has at least one or two amalgam
filling in his/her teeth.
 I have devoted an entire
six page essay to this subject. It
includes documentation
from scientifically respected sources which cite peer reviewed
statistics to help counter the misinformation found on the huge number
of websites which advocate removal of amalgam fillings. Click on
the icon to the right to read these pages. Some of the
information on this page has been reproduced there. |
Amalgam's properties--the reason it has been so successful
 Silver amalgam's
main disadvantage is its
appearance in the teeth. It tends to be gray or black, or sometimes silver
if the patient brushes regularly with a toothpaste that contains an
abrasive. Older forms of amalgam tended to corrode imparting a dark
usually bluish stain to the teeth. This stain could permeate the
dentinal
tubules and is very difficult to remove when replacing the old
filling. The advantages to metallic fillings are that they are incredibly durable, not likely to break, and
last a LONG time. Five to ten years is the
average, however, in a very clean mouth not exposed to too much sugar, twenty years is
not an uncommon lifespan for a well done amalgam. It
is not very technique sensitive, which means that the skill of the dentist
is less important to the wear of an amalgam than it is with the other
types of restorations.
Amalgam
tends to be self sealing which means that once it is placed, a small amount of
corrosion takes place underneath the filling and this corrosion fills
microscopic voids between the tooth and the filling. Moreover, this corrosion is
water resistant and once in place prevents further corrosion and the entry of
fluids containing sugar and bacteria which are the agents that cause more
decay.
This self sealing property is unique to amalgam, and is one of the main reasons
why amalgam fillings resist recurrent decay better than the older, more expensive
cast gold restorations. They are also more reliable than composite
posterior fillings in resisting recurrent decay, especially in patients who use
a lot of sugar. Finally, they are less expensive than gold or composite restorations because they take
less time to place.
| Note: Numerous anti-amalgam organizations and businesses which
promise to remove "toxic" amalgam
restorations or advertise chelation therapy sometimes advertise on this
site. By all means, visit their websites. I allow
this type of advertisement so readers can see some of the nonsense they
sell! |
Resin Composite fillings
(sometimes called "porcelain" fillings)
Having sung the praises of Amalgam restorations, I will now
state flatly that I have given them up in my own practice in favor of the new
generation of composite restoration. The
reasons
follow my description of composite filling materials.
Composite fillings are what people think of when they say
"white fillings" or "porcelain fillings". We call them tooth colored fillings to distinguish
them from amalgam, gold and temporary filling materials.
There are a number of
different formulations of composite filling, but the type most commonly used
today is made of microscopic glass, or porcelain particles of varying shapes and
sizes (depending on the intended use) embedded in a matrix of acrylic. The glass
particles account for between 60% and 80% of the bulk of these materials, so
these restorations could more properly be called porcelain fillings.
The glass particles give the composite restoration their
color (and their stiffness in the unset state). The acrylic is the plastic
matrix that holds the glass particles together. Most composite restorations
today are "light cured" which means that the acrylic remains fluid
until a very bright light is shined on it causing it to harden. Light
curing allows the dentist time to work with the material, building and shaping
it correctly, and when ready, to harden it immediately with the light. The light curing also makes
for a more color stable restoration. The new tooth colored composite
restorations do not get yellow or brown with age as the older ones did.
| The before and after images of the tooth above are impressive, but
do not tell the whole story. In fact, a tooth that is built in
more than 50% restorative material is inherently weak and should be
prepared for a
crown.
This does not mean that all badly damaged teeth should be crowned
immediately. In fact the decay in this one was quite deep.
Deep decay places the nerve in jeopardy, so a plain filling may serve as
a good intermediate restoration to test whether the nerve will die
before a final crown is placed on the tooth. For the full story,
click
here. |
The porcelain particles also give the restoration a great
deal of resistance to wear. Amalgam fillings will probably always wear less than
composite restorations, however the recent advances in particle formulation and
shape have made the newest posterior composites quite competitive for filling
back teeth. Five to seven years is average. Composites are even stronger than amalgams in
shear strength which
makes them better for overlaying large biting areas.
Composite fillings have been used in front teeth for years,
but only recently has the technology in composite formulation improved enough to
allow their common use in back teeth. Prior to acrylic/glass composites, other
types of composites were used in areas where esthetics was important. This is
why even in the early twentieth century people were not forced to have silver
amalgam fillings in their front teeth. However, even in the 1980's the
technology had not yet advanced enough to allow the routine use of composite to
restore chewing areas of the back teeth.
Composite resins are still not as popular with dentists for
repairing back teeth as old-fashioned amalgam. In fact, only about 25% of
dentists currently use them routinely for restoring posterior teeth. The
reasons for this are that they are not as wear resistant as amalgam
restorations, they are more technique sensitive than amalgam, and there is a
tendency for more prolonged tooth sensitivity to cold after the restoration is
done. On the other hand, as the materials continue to improve, they have
become tougher and more wear resistant while improvements in placement
technique have reduced cold sensitivity. However, the greater
difficulty in placing these restorations remains a deterrent for many dentists,
and continues to keep the cost of the service higher than for an a comparable
amalgam restoration.
For those interested in the more technical aspects of
composites and dental cements please click on the button below to visit my page on dental
materials. Here I discuss the different types of composites and cements,
their formulations and their uses.
Post operative discomfort
after fillings (why they sometimes cause prolonged sensitivity to cold or
pressure)
When any type of filling is done on a tooth, some
sensitivity to cold and pressure is normal. This often lasts for as much
as a month after the filling is done. The amount of post operative
discomfort associated with any given filling depends on the depth and extent of
the cavity preparation which in turn depends upon the depth and extent of the
original area of decay or of the old filling which is to be
replaced.
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In many instances the living nerve in the tooth is not
especially healthy at the time the filling is done, and the trauma caused by
removal of the decay or the old filling can push the nerve over the edge
causing an irreversible pulpitis (inflammation of the nerve) which
will lead to the eventual death of the nerve. Situations in which the
nerve of the tooth remains exquisitely sensitive to cold, or hurts
spontaneously without an external stimulus may have a dieing nerve, and the
only solution to this problem is either to perform a
root
canal treatment or
extraction
on the tooth.
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A second problem that can cause prolonged sensitivity to
cold or pressure on a recently filled tooth is hyperocclusion.
This is a technical term that means that the filling is simply too
"high" and strikes the opposing teeth with too much force when the
patient closes his mouth. This can cause very severe sensitivity to
cold and sensitivity to pressure, especially pressure applied to the side of
the tooth. This is a very common problem because the patient is
generally numb when the dentist carves the top of the tooth. The
patient may not be closing into his normal bite and the dentist may miss a
high spot. The solution to this problem is to return to the dentist
for an occlusal adjustment, which means that the dentist determines
what spots on the tooth are high and grinds them down.
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Finally, removal of an old filling or decay may reveal a
crack in the floor of the cavity preparation. This can lead to
cracked
tooth syndrome which means that the tooth hurts whenever pressure is
applied to one or more cusps (points) of the tooth. Cracked teeth
happen all the time in dentistry, and they are one of our most challenging
diagnostic problems. The sudden appearance of cracked
tooth syndrome does not mean that the dentist did something wrong. It
is generally due to a pre existing crack which suddenly allowed the tooth
segments to spring apart when the old filling was removed, or when the
dentist cut a new surface in order to remove decay. The management and
prognosis for cracked teeth is complex and I urge you to read the page I
have provided to explain it.
Composite fillings
present unique technical challenges to the dentist which he or she does not face
when placing an amalgam filling. These difficulties are the primary reason
why many dentists refuse to place composite fillings in back teeth. The
technique for composite fillings is more demanding than that used for amalgam
fillings. Iatrogenic (dentist caused) problems associated
with composite fillings are generally due to one or more of the
following:
-
Undercured composite--Modern composite filling
material begins as a paste which is placed in the cavity preparation after
a proper bonding technique has been performed. The paste is packed
into the tooth and then hardened using a very bright light which triggers
a chemical reaction causing the paste to harden into a very hard tooth
colored filling. As light curing became more and more perfected,
both the composition of the filling material and the construction of the
curing lights evolved over time. Newer curing units (lights) are
extremely bright while the older units were much less bright. A
brighter light means deeper and faster curing of the composite. Many
of the older curing lights were perfected before composite had evolved
enough to be placed into back teeth. Because of the depth of the
fillings in back teeth, many of these older lights are not bright enough to cure
the full depth of a posterior composite filling. This problem can be
overcome by filling the tooth in thin increments and curing each increment
thoroughly before placing the next increment. On the other hand, the
newer arc lights, and laser curing units, which are much more expensive
than the older standard units are so bright that they can cure to a
greater depth quite quickly. (The newest curing unit in dentistry
uses LED's which are less bright, but concentrate the light energy into
wavelengths that are more likely to harden the composite.) If the composite used to fill your
tooth was not cured enough, your tooth will remain sensitive for a very
long time. The only solution for this problem is to remove the
filling and replace it with a properly cured composite or an amalgam.
-
Shrinkage stress--All plastics tend to shrink when
they transform from the liquid to the solid phase (similar to the way water tends to
expand when frozen). Modern composites have been formulated to
minimize this problem, both chemically and by using very dense
concentration of glass particles as fillers. The glass, of course
does not shrink, and much of the contraction caused by the hardening acrylic
matrix is counteracted by the close packing of the glass
particles. (See my page on
dental
composites for more on this.) Even so, some microscopic shrinkage
always happens, and this, when combined with the powerful bonding
techniques available today, can cause the vertical walls of the
preparation to be drawn together which can produce prolonged sensitivity to
cold. If the dentist suspects that this is the case, it is sometimes possible
to release the stresses using a simple technique called
"slicing", in which the dentist cuts a vertical groove from the
top of the filling to the floor of the preparation from mesial (front) to
distal (back) through the filling. This allows the cusps
on either side to rebound relieving the stress. The groove is then
refilled with composite and the filling is then as good as new. This
procedure is fast and easy and saves a lot of time and trauma to the
patient (as well as the dentist).
 Light
cured composites always shrink toward the light source.
Some of the shrinkage away from the walls of the cavity preparation, and to
a to a certain extent away from the floor of the cavity preparation (see
next paragraph) can be avoided by the use of a thin light-guide placed on
the tip of the curing light. This concentrates the light and allows
the dentist to shine the light for a few seconds on each cusp of the
tooth instead of directly on the filling material itself. Thus, the
light channels down the enamel and dentin of the tooth and causes the
initial set of the material to draw toward the cavity prep walls rather than
toward the chewing surface of the restoration. Another way to avoid
shrinkage away from the walls of the prep is to use clear plastic matrix
bands. (A matrix band is used to contain the filling material inside of the
tooth in areas where the walls of the tooth have been breached in order to
remove decay. If a matrix band were not used in these cases, the filling
material would penetrate between adjacent teeth under the gum line, and
would also bond adjacent teeth together. Most dentists use metal bands
due to their ease of use. Click on the image to see how one popular
type of matrix, an Automatrix®, is placed on a tooth.) A clear
plastic matrix allows the curing light to be directed through the plastic
from the side of the tooth. This would cause the composite to be drawn
toward the cavity prep walls and eliminate the shrinkage away from
them. Not too many dentists use a clear plastic matrix due to
the difficulty (some may say "near impossibility") of placing a
thin piece of pliable plastic between tight contacts between two adjacent
teeth.
-
Shrinkage away from the floor of the cavity preparation--As
mentioned above, light cured composites always shrink toward the
light source. Since the light source is usually directed from the top of the tooth,
the composite tends to shrink toward the light, often causing the filling
material to pull away from the floor of the cavity preparation allowing a
tiny void to form underneath the filling between the bottom of the
filling and the tooth surface. This void eventually fills with fluid
and can cause hydrostatic pressure in the
dentinal
tubules which leads to sensitivity to pressure on the filling.
This is the most common reason for pain when biting on a newly done
composite filling. The only solution for this problem is to redo
the filling. The dentist can often avoid this problem by placing the
composite in increments that cover only part of the floor, or by
the use of a self curing glass ionomer base used under the composite.
Why I no longer use amalgam
1. When first invented, amalgam was great stuff. It still
is, in fact, but it isn't any greater now than it was 150 years ago. Technical
improvements in it over the years have made minor differences in its physical
properties, but other than the addition of trace elements to the mix for
the purpose of reducing tarnishing, speeding the setting time and changing
minor physical parameters, it really hasn't changed much since it was
invented. On the other hand the technology involved in composite formulations
has made tremendous strides in improving the wear, strength, appearance,
setting characteristics, water miscibility, and numerous other less obvious
qualities. They continue to improve yearly. The newest generation of composite
filling materials has finally overcome most of the difficulties which
prevented their widespread use in restoring back teeth.
2. Composite fillings are routinely BONDED to the tooth
structure. This takes the place of the water resistant layer of corrosion that
seals amalgam fillings.
It also helps to retain the filling inside the tooth while amalgam fillings depend
on the use of undercuts in the cavity preparation to retain them. Amalgam fillings
must engage undercuts within the cavity preparation so they will not dislodge.
Amalgam also requires a minimum depth of a millimeter and a half in order to
form its crystalline structure while composite fillings have no minimum depth.
(If they are not deep enough, the amalgam will be too thin and tends to
crack.) The use of bonded composites has made possible the use of very small
fillings that do not have the mechanical retention necessary to retain an
amalgam. It has also made possible the use of shallow and thin cavity
preparations which do not require the use of anesthetic to cut due to their
very small size.
Note that it
IS possible to bond amalgam fillings to the tooth. However, the process takes
so long that the cost of such a bonded amalgam filling is actually greater
than the cost of the comparable bonded composite. While most US dentists
still use amalgam, very few of them bond it to the tooth.
3. There is NO comparison between the appearance of a
composite filling and an amalgam. The results are so esthetically superior,
that most people opt for the slightly more expensive composite over the less
expensive amalgam. Since many people have quite a few fillings in their back
teeth, the difference between a mouth with composite fillings versus the same
mouth with amalgams is striking. After a year or so of offering both to
my patients and explaining these differences to them, I discovered that my
amalgam was approaching its maximum shelf life, so I discarded it and never
bought any more.
4. Composite restorations can be repaired while most
amalgam restorations cannot. A tooth has five surfaces that can become
decayed. The size (and cost) of a filling is judged by the number of surfaces
it encompass. When a filling covers, say, 2 surfaces, that leaves three other
surfaces untouched. But if the patient returns a year or two later with decay
in one of those other surfaces, it is usually necessary to replace the entire
amalgam that was done previously in order to place one that encompass the new
decay. But since composite bonds reasonably to itself, the dentist can usually
simply add the new surface to the old filling and avoid the trauma to the
nerve that replacing the entire filling would entail. It is also less
expensive to the patient. (In order to save time, many dentists DO repair old
amalgam fillings, but the interface between the old and new materials is not
chemically sealed as it is when repairing composite fillings.)
5. Before the advent of composite filling materials, many
damaged teeth could not be repaired unless a
root
canal,
post and core and
crown
were done. This was because the working characteristics of amalgam
required stringent techniques which were absolutely necessary, but not always
achievable under real circumstances. Once modern composites became
available, it became possible to repair some of these teeth using
"freehand" techniques impossible with amalgam. Repair of these
teeth is often not technically "perfect", but it offers an affordable
alternative to the stark choices of extraction or a very expensive series of
steps like root canals,
posts and
crowns.
Q. Should I have all my amalgam fillings replaced with
composites? If esthetics is of major concern to the patient, then you
should request the replacement of all your amalgams with composites, or
porcelain crowns. But beware!
Every time you remove one filling and put another in its place, you run the risk
of killing the nerve of the tooth and then needing a
root
canal or
extraction! Remember that the presence of mercury in amalgams is
NOT considered a sufficient reason to replace them, and no dentist should ever
recommend replacing yours on the basis of "mercury poisoning".
We do not solicit the replacement of any old filling provided that it is still serviceable
and the patient does not object to its appearance!
When is it more appropriate to place
a crown on a tooth instead of a filling?
 A
filling is a repair to an otherwise healthy, intact tooth. The term
"filling" implies that the repair should be contained within the
boundaries of that tooth. In other words, the
filling should be surrounded by natural tooth structure insofar as it is
possible. In practice, of course, dentists frequently replace large
sections of teeth with large, bulky fillings. As the filling gets larger
and larger, the amount of natural tooth structure necessary to retain the
filling decreases. The ultimate consequence of this is that the filling
becomes a rickety patchwork of artificial materials that is inherently weak and
may break out at any time. Furthermore, as the natural
tooth structure becomes thinner, replaced by more filling material, it becomes
more and more likely to break off necessitating an even larger repair. The
larger a filling is, the more technically difficult it is for the dentist to do,
and the larger the tooth/filling interface. This means that very large
fillings are likely to be unstable and to leak over time leading to recurrent
decay and replacement with even larger fillings. This process of patching or replacing
already large fillings is what we call "patchwork dentistry". In
most situations, patchwork dentistry ultimately leads to the loss of the tooth,
or at minimum to very expensive methods of repair. If your dentist
recommends placing a crown on the tooth, he is
attempting to stop this cycle of recurrent decay, breakage and repair before it
becomes necessary to do a root canal and
post
and core in order to have anything left above gum line to repair. A
crown is a cast metal covering, generally overlain with porcelain, which is
placed over the tooth in order to hold it together and to withstand the forces
of chewing. Sometimes the entire crown is made out of porcelain in order
to attain the greatest esthetic (appearance) value possible. The crown may
even be made entirely out of gold if that is the wish of the patient.
While no dentist can guarantee that a crown will repair the tooth forever, it is
still the very best restoration possible for a severely damaged tooth, and may
be the only way that some severely damaged teeth can be repaired at
all. The following is a list of reasons that a crown
might be more appropriate than a filling:
-
A tooth should be crowned if the filling would make up more
than half the bulk of the clinical crown of a tooth (that part above the
gum line).
-
A tooth should be crowned if the filling would make up more
than half of the surface area of the clinical crown.
-
A tooth should be crowned if the clinical crown is
cracked
or seriously mechanically weakened.
-
A tooth should be crowned if the filling is very deep under
the gum line since a filling under these circumstances is difficult to do
and is more likely to leak. This leads to recurrent decay a year or
two later.
-
All back teeth with root canals should be crowned as the
tooth structure tends to become brittle after the living nerve is no longer
present.
-
All front teeth that have root canals and also have large
fillings should be crowned.
-
Teeth that are unsightly (ugly) and embarrass the patient
should be crowned. This is especially true in front teeth that have
root canals.
-
Teeth with circumferential decay (decay at the gum line that
encircles more than one surface of the tooth) should be crowned in view of
the near impossibility of properly repairing this type of decay with simple
fillings.
-
Teeth that are worn down due to attrition from bruxing
(grinding and clenching) are often best crowned.
|
Consider
doing it!
When the dentist says you need a crown, you
really ought to think twice before rejecting the advice!
Even though a good dentist can repair almost any
tooth with a filling, he or she may recommend a crown instead.
Lots of people choose the filling anyways since it is always
cheaper. This is often a bad choice. Very
large fillings are technically very difficult to do!
You may leave the office with what looks and feels like a tooth
only to find that a year or two down the line, there is
recurrent decay under the filling. It may be near
impossible for the dentist to make the filling contact the tooth
next to it leaving a gap which jams food between the teeth.
Pieces of the tooth or the new filling may break off over time.
The filling may even have required just enough removal of tooth
structure to cause the nerve to die which will lead to a root
canal followed by a crown, or even an extraction. These
problems are not the fault of the dentist.
There is a limit to what even the best and most
conscientious dentist can accomplish with a very large,
difficult filling. Opting for a filling on a tooth that
the dentist feels needs a crown may be opting for an extraction
a year or two later. |
Temporary filling materials
(ZOE and IRM)
 When a patient presents at my office with pain attributable
to a cavity, I sometimes place a temporary filling in the tooth and reappoint
the patient for a final permanent filling at another visit. Sometimes, this is
done in order to save time, especially if we have slipped the emergency patient
between two regularly scheduled patients. Sometimes it is done in order to save
money.
Temporaries are the least expensive (and most temporary) way to fill a
tooth. Temporary fillings can be done quickly, because they are usually inserted
without any of the time consuming rituals associated with a permanent filling.
The patient is anesthetized, the decay removed and the temporary filling is
mixed and inserted, generally simply by pushing it into the cavity preparation
with a gloved finger. The patient bites into it while it is still soft in order
to adjust the height, and the patient leaves the office without even waiting for a
final set on the material. In a phrase, a temporary is "fast and
cheap'.
But there is another reason that may indicate that a
temporary is the best way to treat the patient, even if time or money is not an
issue. Temporary fillings are different from permanent amalgam or composite
fillings because they are "sedative" fillings. This means that they
tend to soothe an inflamed nerve in a tooth, and may make the difference between
the tooth needing a
root
canal (or an
extraction), or simply filling the tooth later on, after the
nerve has calmed down. Sometimes a temporary filling is the best course to
relieve pain.
Temporary fillings are made of two major components: Oil of
clove (eugenol), which has been used for centuries to relieve toothaches, and
Zinc Oxide which is the ingredient that makes Desitin diaper rash ointment
white. Zinc oxide is an excellent disinfectant. The oil and oxide mix together
to make a stiff paste that eventually hardens into a waterproof substance which
soothes the nerve of the tooth and kills germs while protecting the cavity like
a hard band aid. When used as a temporary filling material or cement, this
material is called "zinc oxide and eugenol", or ZOE for
short.
 Zinc Oxide and Eugenol (ZOE) is not very durable, and it
wears away after just a few weeks, but it works to relieve pain, calm the nerve
and protect the tooth until an appointment can be made to get it filled
permanently. During the Vietnam war, the US Army invented a more durable form of
ZOE called Intermediate Restorative Material (IRM) which is fortified with
plastic powder. (It originally came in red, white or blue colors.) IRM is used almost universally in dental offices throughout the
world for temporary fillings. The increase in durability allows the temporary to
last three to 6 months (sometimes even longer).
Never plan to keep a temporary
filling more than 6 months. They are not meant to last that
long, and while the eugenol lulls the patient into a false sense of security,
the restoration wears rapidly and begins to leak. If you
wait too long, the nerve could die, the temporary
filling will wear away, the tooth will decay further, and then you
will need a root canal or extraction.
How dentists
set their fees
Dental Materials
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