This
darkening is due to changes in the mineral
structure of the tooth, as the enamel
becomes less porous. Teeth can also
become stained by bacterial pigments,
foodstuffs and tobacco.
The
procedure to bleach teeth uses oxidising
agents such as hydrogen peroxide to
lighten the shade of the tooth. The
oxidising agent penetrates the porosities
in the rod-like crystal structure of
enamel and oxidises interprismatic stain
deposits, over a period of time, the
dentine layer, lying underneath the
enamel, is also bleached.
Teeth
whitening / Teeth bleaching / About
teeth whitening products
Teeth
whitening (also referred to as "teeth
bleaching") utilizing at-home tray-based
teeth whitening products has become
the most popular way for dentists to
help their patients obtain whiter smiles.
This type of teeth bleaching system
makes use of a plastic bleaching tray.
Whitening gel is placed into the tray
and it is then seated over the dental
patient's teeth. The bleaching tray
is then worn for multiple hours per
day (or else overnight), for some weeks,
while the effects of the teeth whitening
process take place.
What
are at-home tray-based teeth whitening
systems?
While there are several different systems
a person might use to whiten their teeth
(bleaching teeth), in the last decade
it is tray-based whitening that has
become the most widely utilized at-home
teeth bleaching method. This technique
utilizes a custom formed plastic tray
that fits comfortably over the wearer's
teeth. Bleaching gel (carbamide peroxide)
is placed into this tray and the tray
is then worn for multiple hours a day
(or else overnight), for some weeks,
as the effects of the whitening process
take place whitening gels have been
recognized as safe and effective, what
causes teeth to become darkened or stained,
when does this type of teeth whitening
process work and under what circumstances
might it not, how long you can expect
the teeth whitening effects to last,
the specific steps involved with tray
whitening systems, teeth whitening costs,
and a discussion about side effects
and safety concerns related to carbamide
peroxide teeth whiteners.
Are
at-home tray-based teeth whitening systems
a good choice?
At-home tray teeth whitening can be
a safe and effective way for a person
to bleach their teeth, but it is important
for anyone choosing to utilize this
type of system to realize that essentially
all of their whitening treatments will
be performed on their own, with absolutely
no direct supervision by a dental professional.
Because of this, anyone bleaching their
teeth must be certain that the specific
whitener they are using is safe, and
that they know how to use this product
in an appropriate manner. Failure to
meet either one of these conditions
could result in damage or harm.
About
at-home teeth whitening products: Know
what you're buying.
There are a wide variety of tooth bleaching
products that are available to you as
a consumer, both from your dentist and
also over-the-counter (i.e., drug stores).
You might assume that any tooth whitener
which is available has been approved
by the U.S. Food and Drug Administration
(the "FDA") but this is not
the case. The FDA does not categorize
tooth whiteners as drugs and therefore
it does not regulate them.
As
one of its functions the American Dental
Association (the "ADA") has
chosen to set guidelines for dental
products. These guidelines dictate standards
for both safety and product effectiveness.
In the case of at-home tooth whiteners,
the ADA's guidelines state that a whitener
(when used as directed) must not be
harmful to either teeth or the soft
tissues of the mouth, and that it can
effectively whiten teeth.
A
manufacture can, at their own effort
and expense, present to the ADA findings
drawn from their research and clinical
trials. If the ADA finds that their
guidelines have been met by this data
they will issue to the manufacturer,
for that specific product, the ADA's
"Seal of Acceptance." Since
earning the ADA's seal is expensive
and time consuming for a manufacturer,
and optional, earning this seal clearly
demonstrates a company's commitment
toward creating a quality product. Those
manufacturers who have earned the ADA's
seal will usually display it prominently
on their product's packaging.
You
may discover that the product your dentist
has chosen for your use has not been
granted the ADA's seal. There can be
good reasons for this:
-
As we all know, many products are
manufactured as "generic equivalents."
It is very possible that your dentist
has reviewed the literature detailing
the properties of the product they
have dispensed to you and are satisfied
that it is appropriate. As you might
expect with a generically equivalent
product, its manufacturer might
not seek the ADA's seal as a way
of minimizing the expense of bringing
the product to market.
-
The product you have may contain
a level of carbamide peroxide that
is greater than 10%. As a result
of their clinical experience and
what they have read in dental literature,
your dentist may feel that a whitener
containing a concentration of carbamide
peroxide that is in excess of 10%
is indicated and appropriate for
your use. In this case, you should
always feel free to quiz your dentist
so they can relate their specific
thoughts and rationale to you.
Facts you should know about
"at-home" tooth bleaching
products (as of January, 2006):
-
The only at-home tooth whiteners
(peroxided based) that have yet
been able to earn the ADA's "Seal
of Acceptance" are tray-based
dentist-dispensed products. No over-the-counter
products (such as those sold in
your local store) have earned the
ADA's seal.
-
The active ingredient contained
in all of the at-home tooth whiteners
that have earned the ADA's seal,
and the compound which has been
evaluated in the vast majority of
at-home tray-based bleaching studies,
is carbamide peroxide at a concentration
of 10%. (The active ingredient found
in some over-the-counter at-home
tray-based bleaching products is
not carbamide peroxide but instead
hydrogen peroxide.)
What
influences the shade of teeth?
When will at-home tray-based teeth whitening
work?
At
any point in their lifetime the precise
color of a person's teeth can be influenced
by a multitude of factors. Before the
use of an at-home tray teeth whitening
(teeth bleaching) system is initiated
it is important for your dentist to
evaluate the possible causes of your
tooth discoloration. Having an idea
of what has caused the discoloration
can help your dentist estimate how much
lightening effect the teeth whitening
treatments can be expected to achieve.
-
All
teeth have an intrinsic (baseline)
color.
The teeth of humans, as a race,
display a wide range of different
shades of white. There is no one
specific color that a person's teeth
are supposed to be or should be.
Some people's teeth are just naturally
lighter in color than others.
-
The
coloration of a person's teeth can
be altered by repeated exposure
to chromogenic agents.
It seems to be a fact of life that
as years pass a person's teeth will
have a tendency to stain and discolor.
The degree to which a person's teeth
will darken can often be correlated
somewhat to the amount of exposure
they have had to "chromogenic
agents" such as tea, coffee,
colas, red wine, and tobacco products.
Reasons
why a single tooth might become discolored.
There are times when a single tooth
has experienced certain types of changes
or events and as a result has become
darker than its neighboring teeth. As
an example, it is commonplace that a
tooth that has had root canal treatment
will darken over time. Another common
example is a tooth that has a history
of having been traumatized, such as
having been bumped in an accident. In
this latter case the darkening can be
indicative of a problem associated with
the health of the nerve found inside
the tooth. Any individually darkened
tooth should always be evaluated by
a dentist.
At-home
tray-based teeth whitening can possibly
lighten teeth that have porcelain veneers.
There is an exception to the rule that
existing dental work will not lighten
when a teeth whitening process is used
and this exception involves teeth that
have porcelain veneers on them. Porcelain
veneers are translucent shells of porcelain
that have been bonded onto the front
side of a person's teeth. While the
tooth bleaching agent will not change
the color of the veneer itself it will
be able to permeate the tooth from the
backside, thus lightening the tooth
structure that lies under the veneer.
Because veneers are translucent, the
net effect can be that the tooth, from
the front side, appears whiter.
Complications
associated with trying to whiten teeth
that have gum recession.
Some people have gum recession on one
or more teeth. Usually the root surface
that has become visible because of the
gum recession has an appearance that
is somewhat darker than the rest of
the tooth. This is because root surfaces
are not covered by enamel but are instead
composed of another naturally darker
material termed dentin.
Tray
teeth whitening systems won't effectively
lighten dentin. This means that the
color of the root portion of the tooth
(which shows where the gum recession
has occurred) will not change noticeably
as a result of your bleaching efforts.
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