Toothpaste seems to improve every day. We have anti-cavity
toothpastes, extra-whitening toothpastes, toothpastes with
mouthwash, toothpastes for sensitive teeth, toothpastes with
stripes, clear toothpaste, even liver flavored toothpaste
A modern toothpaste has many things to do. It must have
abrasives to scour off bacterial films. It must have
fluorides to harden the teeth against decay. It must have
a strong enough flavor to hide the bad tastes of decaying
bits of previous meals, and the awful taste of some of the
other ingredients, such as detergents and phosphates.
Toothpaste must have thickeners to stay
on the toothbrush, and squeeze out of the tube. It must
have detergents to remove fatty films, and water softeners
to make the detergents work better, and sweeteners, preferably
non-nutritive, so bacteria are not encouraged.
The most recognized toothpaste ingredient is probably the class
of compounds known as fluorides.
Stannous fluoride was the first
to be used in toothpaste, because it could be used with the
abrasive most common at the time, calcium phosphate. The calcium
prevents sodium fluoride from being
sodium monofluorophosphate was used, as it also could be used
with abrasives common at the time.
When hydrated silica became the
abrasive of choice, sodium fluoride could be used, and is the most
widely used fluoride in toothpastes at this time.
Hydrated silica is the transparent abrasive used in gel toothpastes,
and in the clear parts of striped toothpaste. It has become common
to use it in white opaque toothpastes as well, because of its
compatibility with sodium fluoride.
Fluorides work better in combination with surfactants, which help
the remineralization process. The most common are the lauryl
sulfates, such as sodium lauryl sulfate, or
ammonium lauryl sulfate.
Surfactants (detergents) also help clean the teeth, and provide
a foam that helps to carry away debris. Moreover, lauryl sulfates
have significant anti-bacterial properties, and they can penetrate
and dissolve plaque.
Lauryl sulfates can irritate oral membranes, and so a similar
often replaces some or all of the lauryl sulfate.
Allantoin is sometimes added to
relieve the irritation caused by detergents, alkalies, and acids.
The sequestering agent
(TSPP) removes calcium and magnesium from the saliva, so they
can't deposit on teeth as insoluble deposits called tartar,
In this respect it acts as a water-softening agent.
It won't remove tartar that already exists.
TSPP is slightly alkaline, and has a bitter taste, requiring additional
flavorings to mask it. Also, additional detergents must be added to
keep it in solution. All of these factors can irritate oral
membranes and cause sensitivity.
Polymers such as the
acrylic PVM/MA copolymer are added
to prevent bacteria from breaking down pyrophosphates. Other long
polymers used are
polyethylene glycol (PEG)
in various weights (i.e. PEG-6, PEG-8, PEG-40, etc.), and
polypropylene glycol (PPG).
Sodium bicarbonate (baking soda)
is added for taste and mouth feel. It combines with acids to release
carbon dioxide gas, adding to the foam produced by brushing. It is a
mild abrasive. It may reduce the numbers of acid loving bacteria in
the mouth, although this effect lasts only as long as the mouth stays
Sodium carbonate peroxide
is added to "peroxide" toothpastes as a whitener. It breaks down
into sodium carbonate (washing soda) and hydrogen peroxide. The
hydrogen peroxide bleaches the teeth, and kills germs.
Sweeteners such as
sodium saccharin are added for taste.
Other flavors are usually strong essential oils in the mint
The anti-bacterial agent
is added to kill plaque-forming microbes.
Various gums are used to thicken the paste, but also to retain
moisture, so the toothpaste does not dry out if the top is not
In white pastes,
is used to make the paste opaque and white.
By Simon Quellen Field