| The image at the right shows a patient with crooked canine teeth (eye
teeth) which are twisted, making them look like fangs. The left
central tooth has had a root canal and has darkened. This patient seldom
smiled because of the appearance of his teeth. |
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| The image to the right shows the patient's
smile one hour later. Composite was bonded to the inside of the
canine teeth to close the space between the canines and the lateral
teeth. This gives the "fangs" the appearance of being
straight. The darkened central incisor was shaved back slightly and
composite was bonded over the front to hide the dark color. This
entire procedure was done without getting the patient numb. |
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The images below show how a filling
may be bonded inside a tooth. Bonding a filling
(even
a silver filling can be bonded) tends to make it waterproof. It
also prevents the filling from being dislodged in cases where an unbonded
filling might not stay in place. Once again, this is an example of
direct dental bonding. To see the complex history of this tooth,
click on the image on the right below.
Composite filling materials are actually quite complex, and there are quite a
few different kinds. For a better understanding of the chemical and
physical makeup of composites, as well as a technical explanation of the
different types, please click on the dental material button below:
Indirect dental bonding
(Traditional veneers)
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The following procedure applies to traditional
bonded porcelain veneers. For a discussion of the newest
type of veneer which can be done without preparing, or "drilling
down" the tooth, and hence without shots, click
here. |
In indirect bonding, the artwork is done by a
lab technician on a lab bench, and bonded onto the tooth by the
dentist. The dentist usually prepares the teeth with the handpiece
so that the space where the lab manufactured porcelain veneers
(or filling in the case of back teeth)
will be cemented will allow the insertion of the finished piece without
interferences. That means that the dentist must cut the preparations
so that there is a clear "path of withdrawal" with no
interfering undercuts. When the dentist is finished preparing the
teeth, he or she takes
an impression which is poured with
plaster to create an exact replica of the prepared tooth which is sent to
the lab for fabrication of the appliance
These steps are a form of artwork all by themselves and can be
quite demanding. Between the additional laboratory fees for the
prefabricated restoration and the time it takes to prepare the teeth, this form of dentistry is quite a bit more expensive than
the direct restorations described above (on the order of 5 or more times as
expensive).
Tooth prepared for veneer
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Inserted veneer
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These graphics are reprinted with
permission from Ivoclar Viadent, a company
that manufactures IPS
Empress®, A porcelain system used by dental laboratories to fabricate
all-porcelain crowns and veneers.
The image above on the left shows the dentist making .6 mm
depth cuts in the enamel of the tooth. He or she uses a special bur that
automatically produces the cuts to the proper depth. A medium grit diamond
bur is used next to reduce the remainder of the surface to the the same
depth. After preparation, an impression is taken and sent to the lab for
fabrication of the porcelain veneers.
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Prepared stubby teeth |
veneers inserted |
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Veneers direct from lab |
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The three images above show a case in which the patient's teeth did not show
when she spoke because they were simply too short. She had a space
(diastema) between the central teeth, and the edges were chipped and
irregular. The image to the left shows the teeth after they were prepared
to receive the veneers. Note the shoulder prepared around the edges (margins) of
each tooth. This is done to allow the technician who will fabricate the
veneers to place a sufficient bulk of porcelain for strength and color.
(The porcelain is somewhat translucent, and if it is too thin, and the tooth
structure over which the veneer will be placed is too discolored, which is often
the case, the underlying discoloration may not be completely masked by the
veneer.)
The image on the top left shows a tiny piece of string placed just under the gums around
each tooth. This is kept in place temporarily to retract the gums away
from the margins of the preparations so the impression will be completely clear
and the technician will know exactly where to end the porcelain. The
string was removed after taking the impression, and the patient went home
with the teeth in exactly the condition you see them in above. (No temporary
veneers were placed.) This is possible because the amount of tooth structure
removed is small enough that a layer of enamel is left over the sensitive parts
of the tooth, the preps are not very noticeable by anyone other than the patient
herself, and we usually expect the finished porcelain to be returned within six
working days, so the patient will not remain in this condition for very
long.
The teeth were, in fact lengthened about one and a half millimeters, but the
real magic was accomplished by making the veneers extra thick. This trick
tends to push the lip out slightly, making it a bit fuller. It also does
not allow the lip to drape as low over the teeth as it did without the extra
bulk thus giving the appearance of even longer teeth when the patient's lip is
at rest. The effect is not only startling, but sometimes
disconcerting at first because the patient may feel that the teeth "stick
out too far". Within a few days, the patient gets used to the new
feel of their teeth.
So what's the difference between direct and indirect
restorations besides cost?
In point of fact, both direct and indirect bonded restorations
may look identical when they are first done. The difference is that the
indirect variety are generally made out of porcelain. Porcelain is harder
and more durable than directly placed composites and in general will not wear
over time. It remains shiny indefinitely. The surface of direct
composite veneers will wear over time and lose their shine.
Direct composite veneers frequently finish down to a knife
edge margin in places around the periphery, at least in some areas, and these
very thin areas may "curl" and separate after about three to five
years leaving tiny areas of brown stain here and there. These defects can
usually be repaired, but since indirect porcelain veneers never have knife edge
finishes, and have super hard surfaces, no stain or reduction of the shine ever
takes place. In addition, indirect porcelain fillings in back teeth
have the advantage of not wearing down over time.
Indirect porcelain veneers are more brittle than direct
composite restorations, and are somewhat more likely to fracture after taking a
sharp blow from a hard object such as a coffee mug, or chewing down on something
unexpectedly hard in food. However the newer porcelains are on the order
of 12 times stronger than the older standard porcelains that were used only a
few years ago, and breakage is now fairly rare. If you can afford indirect dentistry,
then porcelain is the way to go. This is the Cadillac in dentistry while the
direct composites are the station wagons.
While most general dentists will do composite fillings in any
teeth, not all of them will do direct composite veneers preferring indirect
porcelain veneers instead. The reason for this is that not all dentists
are able to produce the artwork involved in bonding direct veneers quickly
enough to turn a profit. If you think about it, it makes sense.
There are thousands of dentists all around the country, and every one has
different strengths and weaknesses. In the production of services, time is
money, and some dentists would need to spend too much time trying to get the
contours and color just right. If they offered this service, they would
have to charge such high fees that the price of porcelain would become
increasingly competitive. To understand how this works, click
here.
Indirect Bonding--Lumineers®
Indirect bonding without shots.
 The
newest form of esthetic dentistry involves bonding ultra-thin porcelain veneers,
generally without anesthetic, to unprepared or lightly prepared teeth.
This has been made possible because of a new innovation in dental materials.
LUMINEERS BY CERINATE is a cosmetic solution for permanently stained,
chipped, discolored and misaligned teeth. It may even be used to
revitalize old crowns and bridgework. LUMINEERS are a porcelain
veneer that can be made as thin as a contact lens and are placed over existing
teeth, most of the time without requiring the removal of sensitive tooth structure (unlike
traditional veneers discussed above).
The technology used to fabricate this product involves pressing porcelain
particles into veneers about one third of a millimeter thin. It is
something of a breakthrough because it is difficult to prepare a veneer this
thin with the strength and masking properties necessary to restore broken,
misaligned and discolored teeth.
The advantages to this type of esthetic restoration are as follows:
- Since in most situations, Lamineers require little or no modifications
to the underlying teeth themselves, they can be done from start to finish
without shots most of the time.
- Most cases return from the lab within 7 to 10 working days, so the
patient can expect to receive his or her veneers within two weeks of the
impression appointment.
- Since the veneer is bonded entirely to tooth enamel, the bond is very
strong (the strongest bond in all of dentistry) and the restorations are
clinically proven to last for a minimum of 20 years.
- Lumineer veneers are proprietary which means that the veneers are built
only by certified lab technicians. This is no small consideration
since the dentist cannot "cheap out" by using a discount lab where
technicians are not as well versed in the art. Denmat must maintain
high standards or risk damaging the reputation of the product. The
work that comes back is always very good.
The disadvantages of Lumineers are as follows:
- The Teeth that will receive the lumineers and the gums that surround
them should be in reasonable
condition. There can be no active decay in the teeth, and any fillings
present must be in fairly good condition prior to doing the veneers. With a seriously damaged tooth that
has been extensively repaired
with composite, it is often best to place an all-porcelain
crown on it instead of a veneer. Crowns cover
the entire surface of the tooth and protect it from further decay.
- Oral hygiene must be good before the veneers can be done. If the
hygiene is poor, then the gums may recede away from the margin of the
veneers making the result less than optimum. Also, bleeding gums will
interfere with the bonding process and often causes a line of discoloration
under the porcelain at the gum line.
What can be accomplished with Lumineers?
Discolored teeth
The above teeth show severe
tetracycline stain.
Note that The veneers not only mask the original color of the teeth, but are
used to make the teeth appear longer as well. In this case, eight upper
teeth were veneered as well as eight lower teeth. It is often necessary to
place veneers on more than just the front six teeth because otherwise, the
"smile" would not be wide enough. The veneers may be ordered in
varying degrees of opacity. In this case, relatively opaque veneers were
chosen to mask out the unattractive color of the underlying tooth structure.
Unattractively arranged teeth
These teeth were crooked, as well as yellow and
discolored. Veneers were used to lengthen, straighten and whiten the teeth.
In this case the smile was wide enough to require the veneering of 8 teeth.
It is often financially more feasible to veneer only the four front teeth, but it would then be unwise
to make the veneers much brighter than the color of the existing canine teeth.
Four bright veneers would look "fake" next to the natural color of the canine
(eye) teeth.
This brings up the question of how many teeth to veneer.
The most ideal smile is created by placing veneers on 8 to10 top teeth (from
second premolar on one side to second premolar on the other side) If the
decision is made not to brighten the smile, or otherwise to alter the shape or
form of the arch (the dental arch is shown in the diagram below), it may be
sufficient to veneer as few as two (see "closing spaces" below) or four
incisors.
Closing spaces
In this case, only three teeth were veneered in order to close
the spaces between them (the two central teeth and the patient's left
lateral incisor). This patient whitened his otherwise yellow
teeth with bleaching trays prior to the application of the veneers.
Hollywood smiles--Making a reasonably good smile perfect
In this case, this patient had relatively nice looking teeth
to begin with. However, she spent a lot of time in public and wanted
a perfect smile. In her case, ten veneers were placed (second premolar to
second premolar). This sort of dentistry is becoming more and more
common as the general affluence of the average American increases and dental
awareness spreads because of mass communication, and entertainment shows such as
Extreme Makeover. Note, however, that unlike the veneers done on the
program Extreme makeover, Lumineers require little or no tooth modification, and
almost never require shots to make the patient numb.
Click here to
see a table comparing the physical properties of the various filling and direct
bonding materials used in fillings and veneers
Click here to
see a table comparing the physical properties of the various indirect dental
materials used in veneers , crowns and bridges |
