Toothpastes, used in conjunction with a toothbrush, have probably accomplished more to prevent oral disease than any other oral health procedure.

Depending on the dentifrice, the principal therapeutic outcomes can include

• reduction of caries incidence by assimilation of the fluoride ion into the apatite crystal or enamel (as a result of sodium fluoride, stannous fluoride, sodium monoflurophosphate);
• reduction of tooth hypersensitivity by blocking dentin tubules and thereby reducing fluid exchange(as a result of strontium chloride, sodium citrate, potassium nitrate);
• cosmetic whitening of teeth by peroxides (as a result of hydrogen peroxide) and /or abrasives;reduction of calculus by chelation of divalent cations in saliva (as a result of pyrophosphates or zinc citrate);
• reduction of plaque formation by reducing enzymatic activity of microorganisms and by an antibacterial effect (as a result of triclosan).

In order to put all ingredients of a toothpaste into a stable format, one has to have the following composition. It needs a polishing agent to do exactly as said polish to surfaces of teeth; it needs humectant which allows the paste formulation to be continually moist so the toothpaste will not dry out; it needs a soap as well as a preservative; and a gum to keep the toothpaste together; a sweetener and a flavor to make it pleasant to use; and the cheapest ingredient is the water, which then makes this formulation a usable item in the mouth.

Abrasives

Originally abrasives were chosen on the basis of their effect on dental plaque, calculus and stains. Other considerations were flavor, toxicity and cost. With the advent of fluoride-containing dentifrices, the chemical and physical compatibility of the abrasive with other ingredients in the dentifrice became of prime importance.  This was due to the fact that cleaning agents containing calcium were found to interact with fluoride forming an insoluble compound, calcium fluoride, which rendered it inactive as a decay inhibitor.

There are three essential factors involved for a good polishing agent.
Its size - all of them need to be under 10 micron to ensure that grittiness is not sensed by the user; its shape need to be such that ragged edges will scrape off from deposits of tooth surfaces. And its hardness must be such that it’s hard enough to remove a deposit yet not too hard to harm the enamel surface itself.

The most commonly still used polishing agents (in levels of 15-40%) are aluminum, a by-product of bauxite production. It’s reasonable in price and it has good compatibility with the rest of the ingredients. The most common agent is dicalcium phosphate dehydrate, developed in the early ‘60s or late ‘50s, a uniformly manufactured Ortho/phosphate.

It has low polishing power, yet uniform and is picked as the most commonly accepted dental polishing agent today.
During the early to mid ‘60s, a formulation to develop transparent or translucent toothpaste utilized a polishing agent by the name of silica. This polishing agent is commonly in the toothpaste in two separate formats: Syloid 63 and Syloid 244. These two formats are necessary, one of which is for offering polishing power and the other one to offer the gel with which a toothpaste is made of.

Early ‘60s, the development of fluoride toothpastes necessitated the use of polishing agents which chemically did not prevent the fluorides to be acted. These agents were calcium pyrophosphate as well as some form of silica. Still today, these two polishing agents are used throughout the world to ensure compatibility with the various fluorides used.

Surfactant

The next ingredients of a toothpaste is soap. The most common one of which is sodium n lauryl surcosinate, sodium lauryl sulfate and/or sulfocolaurate. Its need in a toothpaste formulation is to create bubbles, which take the removed debris, encapsulating them in the bubbles and allowing them to float to the surface of the teeth, i.e. help clean the teeth. They are added to the toothpaste at the level of 2-4%.

Surfactants work by lowering the surface tension in the mouth, making it easier to remove foreign materials from the sufaces of the teeth and gums.  The earliest surfactant used was soap, however, this resulted in a relatively high alkaline pH, frequent oral irritation, and interaction with many of the commonly used abrasive agents.

Sweetener

Every toothpaste needs a sweetener. Despite of the international outcry of the dangers of sodium saccharin, it is permitted to be used in a toothpaste  still today all over the world because it is irreplaceable in its flavor. Its level is less than 1%.
The taste of a toothpaste is probably one of the most important factors in its purchase and continuous use. Experience has shown that the majority of consumers will not re-purchase and continue to use a particular toothpaste solely because of its therapeutic benefit.  It must also be pleasant to use and refreshing to the taste.

Often, many of the other ingredients in toothpaste impart a bland or undesirable taste to the base toothpaste. The function of the sweeteners and flavoring agents are to mask this problem.  Saccharin, which provides sweetening without adding calories, is the sweetener most frequently added to toothpastes.

The development of an acceptable flavor for a dentifrice is both an art and a science.  Flavors are usually the single most expensive ingredient in a dentifrice and are chosen carefully to avoid irritation and sensitivity.
The flavors most commonly used in dentifrices include spearmint, peppermint, wintergreen, cinnamon, anise

Flavor

The biggest secret ingredients of any toothpaste is its flavor. Every manufacturer has their own concoction and they are keeping them and aging them at different time intervals and they are all a mixture of essential oils. Their level in a dentifrice and the composition is the highest kept secret in the industry.

Binder

Binders are Hydrophilic agents that prevent separation. Also referred to as gelling agents, binders are hydrophilic or “water loving” compounds that prevent separation of the dentifrice ingredients by providing a stable suspension. 

Binders disperse, swell, or absorb water thereby increasing the consistency of the mixture of liquid and solid phases and preventing the ingredients from separating, particularly during storage.

The first binders used in dentifrices were starch, gum arabic, seaweed and moss.  Binders can be naturally occurring substances or synthetic products. 
The binders most commonly used today are carboxy-methyl cellulose (CMC), xanthan, carbopol, carrageenen (seaweed extract).

These agents are chosen for their ease of dispersion in the mouth, their stability with the other ingredients, and their ability to withstand mold or bacterial contamination.  CMC is used mainly in the US and other countries with temperate climates

Basically this completes the formulation of both cosmetic and therapeutic toothpaste.

Care must be taken that they are stored in containers, i.e. toothpaste tubes and do not interact with the ingredients within and that there is storage stability; is long lived so that on the shelf the toothpaste stays stable for months or years to come despite surface temperatures.