PORCELAIN
CROWNS - OVERVIEW
Dental Crowns for
Your Teeth
As we age, many of us find ourselves
with teeth that are no longer structurally
sound. Root canals, lost fillings,
decay below a filling, chipping
and cracking of the enamel are all
things that can lead to large scale
defects in a tooth's surface. When
the entire surface of the tooth
is a problem, but the root system
is intact, a crown might be just
what the dentist orders.
What
are Tooth Crowns?
Grinding your teeth, an improper
bite, age, fillings and tooth decay
can all be contributing factors
in the wearing down, cracking or
breakage of your teeth. Dental crowns
cover the entire visible surface
of your affected tooth and add strength,
durability and tooth stability.
Who
is a candidate for Tooth Crowns?
Grinding your teeth, an improper
bite, age, fillings and tooth decay
can all be contributing factors
in the wearing down, cracking or
breakage of your teeth. Dental crowns
cover the entire visible surface
of your affected tooth and add strength,
durability and tooth stability.
Dr Phillip F. Ajaje will usually
be able to spot problem areas in
your mouth that might lead to tooth
damage and a need for crowns. Chewing
patterns play a big role as well.
By selectively grinding the tips
of your middle and back teeth (called
cusps) will alter your bite to reduce
the stress on at-risk teeth.
In other instances, crowns are used
to replace a actual missing tooth.
These crowns are anchored to the
teeth on either side, with a bridge
section connecting the two crowns.
Instead of bridges, single tooth
dental implants may be used that
eliminate the need for supporting
the crowns.
How
are Tooth Crowns Attached to your
Tooth?
Dr Phillip F. Ajaje will make an
impression of the tooth and a dental
laboratory will create the crown.
You will typically leave the office
with a temporary crown to wear while
the permanent crown is being made
- this takes about two weeks. The
permanent crown is then cemented
onto your tooth. Typically, only
two visits are required for this
part of the procedure. Often, a
preliminary restoration of your
tooth may be needed before a crown
can be placed. To stabilize your
tooth, a filling must first be put
in place prior to placing a crown
due to the loss of original tooth
structure. Tooth crowns usually
last ten to fifteen years.
Be
sure to discuss with your cosmetic
dentist that the cement colour used
for your permanent crown will be
the same as used for your temporary
crown. A try in paste is used for
this purpose. The colour of the
cement does affect the overall colour
of a porcelain crown, so this needs
to be discussed long before your
temporary crown is placed.
In some cases your cosmetic dentist
may choose to use a Flipper instead
of a temporary crown. A Flipper
is a false tooth to temporarily
take the place of a missing tooth
before the permanent crown is placed.
A Flipper can be attached via either
a wire or a plastic piece that fits
in the roof of your mouth. Flippers
are meant to be a temporary solution
while awaiting the permanent crown.
As the illustration above indicates:
1) a tooth presents with a large
cavity or broken portion of tooth
structure. This tooth is vulnerable
to further decay and fracture.
2) the dentist will 'prepare' or
shape the tooth for a crown. In
preparing the tooth, the dentist
will incorporate resistance and
retention features in order for
the crown to stay in place. These
features vary in every tooth and
are determined by the type of bite
you have. An impression of the prepared
tooth is taken and sent to a dental
laboratory for processing.
3) a crown is then fabricated in
the dental laboratory with instruction
from the dentist such as type of
crown and shade or colour of the
tooth. The crown is then cemented
in place by the dentist. A temporary
crown is placed while the laboratory
is constructing the crown.
Types
of Tooth Crowns
There are basically 2 types of crowns,
those made of ceramic crowns and
metal-ceramic crowns. Metal-ceramic
crowns are extremely durable and
are normally used in molars, where
the forces from chewing and grinding
are most prevalent. Ceramic crowns
are used primarily for front teeth,
since they can best resemble the
natural tooth colour.
All
Porcelain Crowns
The new reinforced resin or bonded
all-porcelain type of crown has
the nicest appearance. This crown
can be made from pure ceramic or
a new reinforced composite resin,
and is almost indistinguishable
from natural teeth. The new bonding
technology involved provides an
exceptional bond your tooth. It
is metal-free, and thus satisfies
the needs of patients with metal
sensitivities. When correcting your
back teeth with bonding, the cosmetic
dentist will perform a tooth coloured
onlay. This type of procedure is
used to correct only those parts
of the tooth that are in need. This
is a metal-free procedure.
Porcelain
fused to Metal Crowns
For a very natural appearance, porcelain
fused to metal crowns are the answer.
However, they have a metal substructure
and require an opaque below the
porcelain. This can make the translucency
of natural teeth difficult to replicate.
Occasionally a darker line will
be visible at the edge of the crown,
near to your gum when it recedes
with age.
Types
of Porcelain
There are basically two types of
porcelain you're likely to hear
and read about most - the felspathic
and pressed ceramic porcelains.
The felspathic type is the original
method that has been around for
20 years. A Ceramist in a dental
lab bakes porcelain onto tin foil
and then heats it in an oven. The
Ceramist is able to create tints
and opaques inside the porcelain
to give the natural look we seek.
Pressed ceramic is created from
a single ingot. The single ingot
is milled in one piece to create
the desired shape. The stains and
opaques are applied only to the
surface of the porcelain to give
a natural look.
Zirconium oxide - One of the most
difficult areas in dentistry today
is the restoration of dental structures
with biocompatible materials that
are strong enough to withstand the
forces of chewing (500-1000lbs pressure
on molar teeth). Recent technology
from Germany now offers a material
that has overcome most of the pitfalls
of present day products. Patients
now have a choice of a material
that is esthetic, strong, pure,
biocompatible and capable of being
used for single and long span dental
bridgework. That material is called
Zirconium oxide.
Pros
and Cons of Dental Crowns Types
Tooth crowns in general add a good
deal of strength to weakened or
worn teeth. Depending on your habits
and the condition of your gums,
there can be some drawbacks. Your
cosmetic dentist will advise which
is best for you given many factors,
including how important appearance
is to you. The following are the
advantages and disadvantages of
the most common crown types.
• Porcelain Crowns
Advantage: Porcelain crowns or new
reinforced resin are considered
to be the most aesthetically pleasing,
as it is so easily matched in colour
to the surrounding teeth.
Disadvantage: The thickness of the
porcelain required for pleasing
aesthetics also requires that more
tooth structure needs to be removed.
It is more difficult for your cosmetic
dentist to get an ideal fit where
your gum meets the crown. Gingival
inflammation appears to be more
common with porcelain crowns than
gold crowns. All-porcelain crowns
require a higher skill level from
your dentist and lab.
• Porcelain Fused-to-Metal
Crowns
Advantage: Porcelain fused-to-metal
crowns have a very natural appearance.
Disadvantage: They have a metal
substructure and require an opaque
below the porcelain. This can make
the translucency of natural teeth
difficult to replicate. Occasionally
a darker line will be visible at
the edge of the crown, near to your
gum when it recedes with age.
If
you require any more information
on EMERGENCY DENTISTRY IN
SYDNEY please do not hesitate
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