How Toothpaste Keeps Your Teeth, Gums & Mouth Healthy

Written & Reviewed by Dr David Chen

Toothpastes work topically by applying a paste to the surfaces of teeth which provides various benefits depending on the ingredients in its formulation.

Toothpaste Collection
Various toothpastes

The key to what makes toothpastes different from one another is due to the ingredients or rather the combination of ingredients in the paste.

We will explain what ingredients provide each benefit and how it does so.

Cavity prevention

A major benefit in using toothpaste is for its anti-cavity effects. It can help prevent tooth decay as well as acid erosion by strengthening teeth, protecting them, and repairing enamel damage.

The two toothpaste ingredients which have been proven to provide anti-cavity benefits are fluoride and hydroxyapatite.


Fluoride is a naturally occurring mineral with multiple cavity protective effects.

Benefits of fluoride in toothpaste for teeth:

  • Inhibits demineralization
  • Enhanced remineralization
  • Inhibits bacterial activity

Inhibition of demineralization

Fluoride can inhibit teeth from demineralizing (loss of tooth minerals) by making them more resistant to acid dissolution. It does so by strengthening the teeth by converting the hydroxyapatite tooth crystals to fluorapatite.


The default mineral for teeth is in the form of hydroxyapatite but upon converting to fluorapatite, it gains multiple benefits.

  • Increased resistance to acid dissolution.
  • Decreases mineral solubility.
  • Increased stability of mineral structure.
  • Promotes remineralization to reverse cavities.

In summary, it makes your teeth stronger. It can even lower the critical pH from 5.5 to 4.5 for when the enamel begins to dissolve.

critical ph of hydroxyapatite and fluorapatite
Credit: Adam hellen

Enhancement of remineralization

Studies have shown that demineralized tooth surfaces will more readily uptake fluoride than non-demineralized surfaces. This results in an acceleration of remineralization because fluoride will attract the tooth minerals, calcium and phosphates, to help repair the enamel.

demineralization remineralization of enamel-plaque-saliva interface
Credit: Adam Hellen

Inhibition of bacterial activity

The antibacterial effects of fluoride have been well established but there is a lack of consensus on how much it contributes in preventing cavities.

The two effects which fluoride has on bacteria:

  • Inhibits metabolism of glucose (glycolytic enzyme enolase activity)
  • Inhibits proton-extruding adenosine triphosphate (H+/ATPase) for molecular transport

Essentially what the fluoride does is interfere with the bacteria’s ability to process sugar and take in sugar from the mouth. In layman’s terms, the bacteria will starve to death when exposed to excess fluoride.


Hydroxyapatite toothpastes have demonstrated remineralization capabilities that were comparable to fluoride. Studies typically found that the differences between the two remineralizing agents were not statistically significant thus making it a viable fluoride alternative.

Davids sensitive+whitening toothpaste with metal tube key inserted
hydroxyapatite toothpaste

However the mechanism via how it remineralizes teeth is slightly different than that of fluoride.

How nano-hydroxyapatite remineralizes teeth:

  • In demineralized enamel, nano-hydroxyapatite inserts itself into the tooth to replace the missing minerals, calcium and phosphate.
  • In dentin, it penetrates into the collagen matrix and acts as a scaffold by providing calcium and phosphate locally.
  • It forms a synthetic enamel layer that covers the tooth which can act as a buffering solution when dissolved.

These are all protective effects which help repair the tooth and prevent future damage.

Plaque removal

How toothpaste removes plaque is by using abrasives, detergents and anti-tartar agents in its formulation.


Toothpaste abrasives have a gritty texture to them which can help mechanically/physically remove food and plaque from teeth.

Examples of abrasives:

The toothbrushing motion is what rubs the abrasives onto the enamel surface thus facilitating the removal of plaque and food. The action is akin to scrubbing a dinner plate with stuck food on it.


Yes, there are detergents in toothpaste and the most commonly known one would be SLS. They help clean the teeth by wetting its surface which facilitates the removal of plaque and food.

Examples of detergents in toothpaste:

Anti-tartar agents

Some ingredients such as the family of pyrophosphates act as anti-tartar and anti-staining agents. They prevent calculus from building up and also prevent stains from sticking onto the surfaces of teeth.

Examples of anti-tartar ingredients:

  • Calcium Pyrophosphate
  • Disodium Pyrophosphate
  • Tetrapotassium Pyrophosphate
  • Tetrasodium Pyrophosphate

        Sensitivity reduction

        Toothpastes can contain desensitizers which help alleviate tooth sensitivity. There are two mechanisms and consequently two types of anti-sensitivity agents, nerve depolarizers and tubular occlusion agents.

        That is the basis for how sensitive toothpastes work.

        Nerve depolarization

        Nerve depolarizers work by supplying an overabundance of potassium ions to the tooth nerve thus disrupting the natural concentration gradient. This interferes with action potential generation thus prevents elicitation of pain signals.

        crest depolarization repolarization with potassium nitrate
        Credit: Crest

        The end result is a reduction in dentin hypersensitivity. Essentially the tooth nerve will be numb so it simply won’t respond to external stimuli.

        Examples of nerve depolarizing toothpaste ingredients:

        Tubular occlusion

        Tubular occlusion agents reduce teeth sensitivity by occluding exposed dentinal tubules thus preventing stimuli from interacting with the tooth nerve.

        Colgate Sensitive Pro Relief - tubular occlusion
        Credit: Colgate

        You can think of teeth as having pores which lead directly to the nerve. When these pores are wide open, stimuli can enter and reach the nerve. However, if you clog the openings, that interaction will be prevented.

        Examples of tubular occlusion anti-sensitivity agents:

        Teeth whitening

        There are two different types of whitening ingredients in toothpastes and they can whiten your teeth via two different mechanisms, mechanical stain removal and chemical bleaching.

        These two mechanisms are the basis for how whitening toothpastes work.

        Mechanical removal of stains

        Mechanical teeth whitening involves using abrasives within the toothpaste to scrub away stains on the exterior surface of the teeth.

        Examples of whitening abrasives:

        • Hydrated silica
        • Mica
        • Calcium carbonate
        • Sodium bicarbonate

        What we mean by mechanical abrasion is similar to using a sponge and scrubbing a food stained dinner plate. When you remove that piece of stuck food, it is now cleaner and whiter.

        This is a very physical process and once the stains on the surfaces of the teeth have been removed, the teeth will appear whiter. However, this probably isn’t what you think of when you hear the words teeth whitening.

        Chemical bleaching of stains

        Some whitening toothpastes contain hydrogen peroxide which can chemically bleach your teeth by oxidizing intrinsic stains. This is the same whitening method that your dentist uses for in-office whitening sessions.

        Colgate Optic White Renewal Vs Pro Series Toothpaste
        Peroxide based toothpastes

        Peroxide is the only ingredient that can chemically whiten your teeth because it can form powerful free radicals that oxidize intrinsic stains.

        hydrogen peroxide decomposition to radicals - reaction equations
        Hydrogen peroxide forms free radicals

        How hydrogen peroxide whitens teeth:

        1. Peroxide will form free radicals that can diffuse through the tooth.
        2. It oxidizes stains by converting double bonds to single bonds.
        3. Stains with less double bonds will absorb less light and reflect more of it, thus appearing whiter in color.
        Hydrogen peroxide oxidation of double bonds
        Credit: Clifton Carey

        Alternative toothpaste bleaching agent

        Peroxide tooth bleaching has been in use for decades but recently a new ingredient called PAP has arrived on the market. It can also chemically oxidize tooth stains but without the use of free radicals.

        Hismile PAP+ whitening toothpaste - unboxed next to box
        Hismile PAP+ Whitening Toothpaste

        The most prominent PAP toothpaste would be the Hismile PAP+ whitening toothpaste.

        Bad breath suppression

        Toothpastes which namely contain zinc in its formulation do possess the potential to reduce bad breath.

        Studies have shown that products which contain zinc can inhibit production of volatile sulfur compounds (VSC). VSCs have been found to be related to the cause for halitosis (bad breath) and they are produced by bacteria in the mouth.


        Toothpastes work by exerting its effects topically when the paste is applied directly onto the surfaces of teeth. Its benefits are derived from the ingredients within the paste which means different ingredients will have different effects.


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