DENTAL
PROCEDURES Teeth
Whitening
In
the world of cosmetic
dentistry, teeth whitening
reigns supreme. Universally
valued by men
and women alike, whitening
(or bleaching) treatments
are available to satisfy
every budget,
time frame and temperament.
Whether
in the form of one-hour
bleaching sessions at
your dentist’s
office, or home-use
bleaching kits purchased
at your local drugstore,
teeth whitening solutions
abound. Yet
only 15 percent
of the population has
tried the cosmetic procedure,
and misinformation
on the subject
is rife.
The
long and the short of
it is that teeth whitening
works. Virtually everyone
who opts for
this cosmetic treatment
will see moderate to
substantial improvement
in the brightness
and whiteness of their
smile. However, teeth
whitening is not a permanent
solution and
requires maintenance
or "touch-ups" for
a prolonged effect.
Bleaching vs. Whitening
According
to the FDA, the term "bleaching" is
permitted to be used
only when the teeth
can be whitened beyond
their natural color.
This applies strictly
to products that contain
bleach — typically
hydrogen peroxide or
carbamide peroxide.
The
term "whitening," on
the other hand, refers
to restoring a tooth’s
surface color by
removing dirt and debris.
So any product that
cleans (like a toothpaste)
is considered
a whitener. Of course,
the term whitening sounds
better than bleaching,
so it is
more frequently used — even
when describing products
that contain bleach.
Why Teeth Whitening? Examining Enamel
Most
of us start out with
sparkling white teeth,
thanks to their porcelain-like enamel
surface. Composed of
microscopic crystalline
rods, tooth enamel is
designed to protect
the teeth from the
effects of chewing,
gnashing, trauma and
acid attacks caused
by sugar.
But over the years enamel
is worn down, becoming
more transparent and
permitting
the yellow color of
dentin — the tooth’s
core material — to
show through.
During
routine chewing, dentin
remains intact while
millions of micro-cracks
occur in the
enamel. It is these
cracks, as well as the
spaces between the crystalline
enamel
rods, that gradually
fill up with stains
and debris. As a result,
the teeth eventually
develop
a dull, lackluster appearance.
Teeth
whitening removes the
stains and debris, leaving
the enamel cracks open
and
exposed. Some of the
cracks are quickly re-mineralized
by saliva, while others
are filled
up again with organic
debris.
Tooth Discoloration: The Two Types of Tooth Stains
There
are two categories of
staining as it relates
to the teeth: extrinsic
staining and
intrinsic staining.
Extrinsic
stains are those that
appear on the surface
of the teeth as a result
of exposure to
dark-colored beverages,
foods and tobacco, and
routine wear and tear.
Superficial extrinsic
stains are minor and
can be removed with
brushing and prophylactic
dental cleaning.
Stubborn extrinsic stains
can be removed with
more involved efforts,
like teeth
bleaching. Persistent
extrinsic stains can
penetrate into the dentin
and become ingrained
if they are not dealt
with early.
Intrinsic
stains are those that
form on the interior
of teeth. Intrinsic
stains result from trauma,
aging, exposure to minerals
(like tetracycline)
during tooth formation
and/or excessive
ingestion of fluoride.
In the past, it was
thought that intrinsic
stains were too resistant
to be corrected by bleaching.
Today, cosmetic dentistry
experts believe that
even
deep-set intrinsic stains
can be removed with
supervised take-home
teeth whitening
that is maintained over
a matter of months or
even a year.
What Causes Tooth Staining?
Age: There
is a direct correlation
between tooth color
and age. Over the years,
teeth darken
as a result of wear
and tear and stain accumulation.
Teenagers will likely
experience
immediate, dramatic
results from whitening.
In the twenties, as
the teeth begin to show
a yellow cast, teeth-whitening
may require a little
more effort. By the
forties, the yellow
gives
way to brown and more
maintenance may be called
for. By the fifties,
the teeth have
absorbed a host of stubborn
stains which can prove
difficult (but not impossible)
to remove.
Starting
color: We
are all equipped with
an inborn tooth color
that ranges from yellow-
brownish to greenish-grey,
and intensifies over
time. Yellow-brown is
generally more
responsive to bleaching
than green-grey.
Translucency
and thinness: These
are also genetic traits
that become more pronounced
with age. While all
teeth show some translucency,
those that are opaque
and thick
have an advantage: they
appear lighter in color,
show more sparkle and
are
responsive to bleaching.
Teeth that are thinner
and more transparent — most
notably the front teeth — have
less of the pigment
that is necessary for
bleaching.
According to cosmetic
dentists, transparency
is theonly condition
that cannot be corrected
by any form of teeth
whitening.
Eating
habits: The
habitual consumption
of red wine, coffee,
tea, cola, carrots,
oranges
and other deeply-colored
beverages and foods
causes considerable
staining over the
years. In addition,
acidic foods such as
citrus fruits and vinegar
contribute to enamel
erosion.
As a result, the surface
becomes more transparent
and more of the yellow-colored
dentin
shows through.
Smoking
habits: Nicotine
leaves brownish deposits
which slowly soak
into the tooth
structure and cause
intrinsic discoloration.
Drugs
/ chemicals: Tetracycline
usage during tooth
formation produces
dark grey or
brown ribbon stains
which are very difficult
to remove. Excessive
consumption of
fluoride causes fluorosis
and associated areas
of white mottling.
Grinding: Most
frequently caused by
stress, teeth grinding
(gnashing, bruxing,
etc.) can
add to micro-cracking
in the teeth and can
cause the biting edges
to darken.
Trauma: Falls
and other injuries can
produce sizable cracks
in the teeth, which
collect large amounts
of stains and debris.
Teeth Whitening options
Three
major teeth whitening
options are available
today. All three rely
on varying
concentrations of peroxide
and varying application
times.
In-Office Whitening
Significant
color change in a short
period of time is the
major benefit of in-office
whitening.
This protocol involves
the carefully controlled
use of a relatively
high-concentration peroxide
gel, applied to the
teeth by the dentist
or trained technician
after the gums have
been
protected with a paint-on
rubber dam. Generally,
the peroxide remains
on the teeth for
several 15 to 20 minute
intervals that add up
to an hour (at most).
Those with particularly
stubborn staining may
be advised to return
for one or more additional
bleaching sessions,
or may be asked to continue
with a home-use whitening
system.
Cost: $ per visit (on average) nationwide.
Professionally
Dispensed Take-Home
Whitening Kits
Many dentists are of
the opinion that professionally
dispensed take-home
whitening
kits can produce the
best results over the
long haul. Take-home
kits incorporate an
easy-to-use lower-concentration
peroxide gel that remains
on the teeth for an
hour
or longer (sometimes
overnight). The lower
the peroxide percentage,
the longer it may
safely remain on the
teeth.
The gel is applied to
the teeth using custom-made
bleaching trays that
resemble mouth
guards.
Cost: $ to $.
Over-the-Counter Whitening
The
cheapest and most convenient
of the teeth whitening
options, over-the-counter
bleaching involves the
use of a store-bought
whitening kit, featuring
a bleaching
gel with a concentration
lower than that of the
professionally dispensed
take-home
whiteners. The gel is
applied to the teeth
via one-size-fits-all
trays, whitening strips
or paint-on applicators.
In many cases this may
only whiten a few of
the front teeth
unlike custom trays
that can whiten the
entire smile.
Cost: $ to $.
Hydrogen Peroxide vs. Carbamide Peroxide
The
bleach preference for
in-office whitening,
where time is limited,
is powerful and
fast-acting hydrogen
peroxide. When used
in teeth bleaching,
hydrogen peroxide
concentrations range
from approximately nine
percent to 40 percent.
By
contrast, the bleach
of preference for at-home
teeth whitening is slower
acting
carbamide peroxide,
which breaks down into
hydrogen peroxide. Carbamide
peroxide
has about a third of
the strength of hydrogen
peroxide. This means
that a 15 percent
solution of carbamide
peroxide is the rough
equivalent of a five
percent solution of
hydrogen peroxide.
How White Can You Go? A Matter of Esthetics
Teeth
whitening results are
subjective, varying
considerably from person
to person. Many
are immediately delighted
with their outcome,
while others may be
disappointed. Before
you
embark on any whitening
treatment, ask your
dentist for a realistic
idea of the results
you are
likely to achieve and
how long it should take
to achieve them. Expectations
play a major role
in teeth whitening.
Shade guides help your
dentist determine the
most natural white for
you.
Whitening Shade Guides
In
the dental office, before-and-after
tooth color is typically
measured with shade
guides.
These are hand-held
displays of wide ranges
of tooth colors. (Dentists
also use them in
choosing crown and other
restoration shades.)
The
standard-setter among
them has long been the
Vitapan Classic Shade
Guide. This
shade guide standard
incorporates 16 shades,
systematically arranged
from light to dark
into four color
groups, and provides
a universal tooth-color
terminology.
While
whitening can occasionally
lighten tooth color
by nine or more shades,
most of those
who bleach their teeth
are likely to see a
change of two to seven
shades.
Teeth Whitening Risks
Teeth
whitening treatments
are considered to be
safe when procedures
are followed as
directed. However, there
are certain risks associated
with bleaching that
you should be
aware of:
Sensitivity: Bleaching
can cause a temporary
increase in sensitivity
to temperature, pressure
and touch. This is likeliest
to occur during in-office
whitening, where higher-concentration
bleach is used.
Some individuals experience
spontaneous shooting
pains (“zingers”)
down
the middleof their front
teeth.
Individuals at greatest
risk for whitening sensitivity
are those with gum recession,
significant
cracks in their teeth
or leakage resulting
from faulty restorations.
It has also been reported
that redheads, including
those with no other
risk factors, are at
particular risk for
tooth
sensitivity and zingers.
Whitening
sensitivity lasts no
longer than a day or
two, but in some cases
may persist up
to a month. Some dentists
recommend a toothpaste
containing potassium
nitrate for
sensitive teeth.
Gum
irritation: Over
half of those who
use peroxide whiteners
experience some degree
of
gum irritation resulting
from the bleach concentration
or from contact with
the whitening trays.
Such irritation typically
lasts up to several
days, dissipating after
bleaching has stopped
or
the peroxide concentration
lowered.
Technicolor
teeth: Restorations
such as bonding, dental
crowns or porcelain
veneers are
not affected by bleach
and therefore maintain
their default color
while the surrounding
teeth
are whitened. This results
in what is frequently
called “technicolor
teeth.”
Maintaining
Your Whiter Smile
To extend the longevity of newly whitened teeth, dentists are likely to recommend:
At-home
follow-up or maintenance
whitening — implemented
immediately or performed
as infrequently as once
a year.
Avoiding dark-colored
foods and beverages
for at least a week
after whitening.
Whenever possible, sipping
dark-colored beverages
with a straw.
Practicing excellent
oral hygiene — brushing
and flossing after meals
and at bedtime.
Caveats
In
addition to the aforementioned
risk factors, a number
of caveats should be
considered
before undergoing teeth
whitening:
No
amount of bleaching
will yield “unnaturally” white
teeth.
Whitening results are
not fully seen until
approximately two weeks
after bleaching. This
is
an important consideration
if you are about to
have ceramic restorations
and want to be sure
the color matches that
of your newly bleached
teeth.
To avoid the technicolor
effect, tooth-colored
restorations will likely
need replacement
after bleaching.
Recessed gums often
reveal their yellowish
root surfaces at the
gum line. That yellow
color
has proven difficult
to bleach.
Pregnant or nursing
women are advised to
avoid teeth whitening.
The potential impact
of swallowed bleach
on the fetus or baby
is not yet known.
For more information visit our FAQ page.