INTRODUCTION

Toothpaste is colloidal substance used for hygienic and cosmetic

purposes. It consists of an abrasive, a detergent, a binder, a humectant,

a sudser, water, plus some additional substances like sweeteners,

flavorings, and coloring agents. Most toothpastes also contain a

fluoride compound as well as a compound that helps to prevent tartar

build up. Nearly all toothpastes these days have some sort of whitening

agent as well. Toothpastes for sensitive teeth, like Sensodyne, also

contain some desensitizing agents to reduce sensitivity.

HISTORY

Toothpaste has been around for over 4,000 years. Originally its purpose

was solely cosmetics. It wasn’t until the 20th century that modern

toothpaste was invented with the purpose of removing foreign particles,

like pieces of food, from your mouth.

Because the purpose was removing stains, harsh abrasives were used as

the primary ingredient. Some of these ingredients include verdigis,

ground fish bones, sand and pumice, table salt, and even strong acids.

It was finally invented as we know it, or similar, by a 23-year old dental

surgeon, with chalk being one of the primary ingredients, and it was

sold in jars.

ABRASIVES

Every toothpaste contains some sort of an abrasive compound that does

most of the cleaning. It works to remove stains, plaque, and foreign

particles from your mouth. Some common abrasives are hydrated silica,

calcium carbonate, and sodium bicarbonate.

Most abrasives are gentle enough that they pose no harm to your teeth. Too

strong of abrasives can damage teeth by wearing away enamel. This

can lead to the exposure of dentin, the sensitive material which make

up your teeth, leading to discomfort.

DETERGENTS & SUDSERS

Like abrasives, detergents are used in toothpaste to clean. They

supplement the abrasives because detergents are surfactants, so they

interact well with both the stain or particle and the water, helping to

more effectively remove them. The most commonly used detergent is

sodium lauryl sulfate but sodium bicarbonate also acts as a detergent.

This detergent also acts as the most common sudser. A sudser is also a

surfactant, so it lowers the surface tension of water, allowing bubbles to

form more easily. The foam helps clean more efficiently by expanding

the volume, dislodging particles, and give a better feel to the user.

BINDERS

Binders are what hold the solid and liquid parts of toothpaste together and

thicken the ingredients to make them into the colloidal substance.

Without the binder the toothpaste would be more like a suspension

where the solid parts would settle out and need to be shaken or stirred

before use, like paint. Some common binders are karaya gum,

bentonite, sodium alginate, methylcellulose, carrageenan, and

magnesium aluminum silicate.

HUMECTANT

Humectant acts as a moisturizer for the toothpaste. Without it, the paste

would easily dry out. Because the paste is made of both solid and liquid

parts, the humectant helps keep them together, along with the binder.

Commonly used humectants are sorbitol and glycerin. These two

compounds, and others used as humectants, often add coolness or

sweetness to the toothpaste.

FLUORIDE, SWEETENERS & FLAVORINGS

It’s standard for toothpastes to contain some form of fluoride, which

strengthens tooth enamel and prevents decay. Because our saliva and

the plaque that builds up are naturally acidic, they can, over time,

dissolve the enamel. Scientists are still not completely sure how

fluoride repairs the enamel, but they believe it happens through a series

of chemical reactions called remineralization. Commonly used fluorides

are sodium fluoride, sodium monofluorophosphate, and stannous

fluoride.

Most toothpastes contain some supplemental sweetening to enhance the

flavor. Saccharin is the most commonly used artifical sweetener

because it has a long shelf life and does not contribute to the formation

of cavities.

It is common for toothpastes to have some flavoring to enhance the taste.

Usually the flavor added is some variety of mint, because it is

associated with freshness.

COLORING, BLEACHING & DESENSITIZING

AGENTSColoring appears on toothpaste simply because they make them more

aesthetically pleasing. Colors are mixed in separate vats, and then

carefully combined in the correct proportion to the toothpaste before

being pumped into the tube.

Nearly all toothpastes contain a bleaching agent because many people

wish to have whiter teeth and remove stains. Two common bleaching

agents are carbamide peroxide and citric acid.

Desensitizing agents are popular in select brands of toothpastes for people

who experience sensitivity to hot and cold due to the exposure of the

sensitive dentin. Some common desensitizing agents are sodium

fluoride, strontium chloride, and potassium nitrate.

PREPARATION

Essentially toothpaste is made by

combining all the aforementioned

ingredients into a large vast and

mixing them all together. Each

measurement is taken manually,

then mechanically to ensure

efficiency.

After the toothpaste is mixed, the

tubes are prepared by being

cleaned in blowers and vacuums

to remove all dust particles.

The final step before boxing a

shipping is stamping on the

expiration date.

EXPIRATION

Most toothpastes have expiration dates that are about two years from the

manufacture date. The ADA requires that toothpaste has an expiration

date because it contains fluoride, which loses potency over time.

Despite being a colloid, many toothpaste manufacturers claim that their

toothpastes will separate out over time, which is another reason for the

expiration date.

The compounds containing the flavor can also dissipate over time, which

would cause the paste to have a bad taste.