TOOTHPASTE


One of the most common ways to prevent plaque formation is by brushing your teeth. This technique employs a mechanical method of removing plaque. Brushing your teeth for two minutes at least twice a day and flossing can help remove plaque (Health Canada, 2009). Toothpaste can also be used to provide additional chemical protection for your teeth.
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Common components of toothpaste


This table illustrates common components that are added to toothpaste to fulfill a variety of functions. Abrasives help remove plaque mechanically during brushing. Surfactants are important for controlling stains on the teeth. Other components such as colours, sweeteners and flavours are added to make products more appealing to use (Davies et al., 2010).
Abrasives
Surfactants
Humectants
Alumina
Aluminium trihydrate
Bentonite
Calcium carbonate
Calcium pyrophosphate
Dicalcium phosphate
Kaolin
Methacrylate
Perlite (a natural volcanic glass)
Polyethylene
Pumice
Silica
Sodium bicarbonate
Sodium metaphosphate
Amine fluorides
Dioctyl sodium sulfosuccinate
Sodium lauryl sulfate (SLS)
Sodium N lauryl sarcosinate
Sodium stearyl fumarate
Sodium stearyl lactate
Sodium lauryl sulfoacetate
Glycerol
PEG 8 (polyoxyethylene glycol esters)
Pentatol
PPG (polypropylene glycol ethers)
Sorbitol
Water
Xylitol
Gelling or binding agents
Flavours
Preservatives
Carbopols
Carboxymethyl cellulose
Carrageenan
Hydroxyethyl cellulose
Plant extracts (alginate, guar gum,
gum arabic)
Silica thickeners
Sodium alginate
Sodium aluminum silicates Viscarine
Xanthan gum
Aniseed
Clove oil
Eucalyptus
Fennel
Menthol
Peppermint
Spearmint
Vanilla
Wintergreen
Alcohols
Benzoic acid
Ethyl parabens
Formaldehyde
Methylparabens
Phenolics (methyl, ethy, propyl )
Polyaminopropyl biguanide
Colours
Film agents
Sweeteners
Chlorophyll
Titanium dioxide
Cyclomethicone
Dimethicone
Polydimethylsiloxane
Siliglycol
Acesulfame
Aspartame
Saccharine
Sorbitol

Plaque Prevention


In addition to providing a mechanical means of removing plaque, many types of toothpaste contain chemical agents that inhibit plaque formation. Since plaque formation is highly dependant on the attachment of bacteria, most anti-plaque components are antiseptics or antimicrobials, which prevent biofilm attachment, prevent bacteria from dividing and proliferating, or remove plaque that has adhered to the surface of the teeth. Agents must also taste good, be compatible with other toothpaste components, have low toxicity and not disrupt the normal ecology of the oral cavity. The anti-plaque agents adsorb to the surface of the teeth, then slowly desorb, providing protection for a prolonged period of time. However, frequent brushing is necessary to ensure anti-plaque agents are not completely desorbed. The rate of desorption of a substance is called its substantivity (Davies et al., 2010).

Triclosan

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Triclosan (2,4,4’ trichlor-2’-hydroxydiphenyl ether) is a commonly used agent that is also used in deodorants and soaps. One of the advantages of this agent is that is does not interact with fluoride or surfactants in toothpaste. It functions by inhibiting enoyl-reductase enzymes of type II fatty acid synthesis in bacteria. This causes damage to the bacteria’s cytoplasmic membrane. When the membrane is damaged, the bacteria dies, which prevents plaque formation. It is effective against both gram positive and gram negative bacteria
(classification based on characteristics of cell wall). Another advantage of triclosan is that it neutralizes bacterial products which could otherwise lead to inflammation.

Although triclosan only has moderate substantivity, it can be combined with a co-polymer (polyvinylmethyl ether maleic acid) to increase its substantivity. The polymer has two primary groups: a solubilising group and an attachment group. Triclosan is maintained in surfactant micelles by the solubilising group. In the liquid adherent layer, the attachment group reacts with the surfaces of the oral cavity via calcium. Triclosan is then released into the salivary environment slowly.

However, some studies have suggested that triclosan can react with water to form chloroform, which is toxic if inhaled in large quantities and can lead to liver problems, depression and cancer. On the other hand, some studies have shown that triclosan could have chemotherapeutic potential in preventing cancer (Davies et al., 2010).

Stannous fluoride

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Stannous fluoride (SnF2) is a compound that was first used for dental applications in the 1950s. Although it was first introduced as an anti-caries agent, it was found that the stable tin ion could reduce the amount of bacteria present in saliva. However, the compound must be stabilized as either stannous gluconate or stannous pyrophosphate. Unfortunately, stannous gluconate causes staining of the teeth and is therefore not a good choice for use in toothpaste (Gaffer et al., 2007).

Polyvinyl phosphonic acid (PVPA)


Another approach to preventing plaque formation is preventing the attachment of the bacteria to the surface of the teeth. Although the complete mechanism is unknown, it is suspected that electrostatic forces, hydrophobic attraction and lectin-like interactions all play a role in bacterial attachment. By interfering with these attachment mechanisms, PVPA has been shown to effectively reduce attachment of Strep. Mutans and A viscosus by 90%. This was shown to lead to a 36% reduction is plaque formation. PVPA adsorbs strongly to teeth due to its high affinity for enamel. Another advantage of PVPA is that because it is non-bactericidal, it does not interfere with the normal microbial ecology of the oral cavity (Gaffer et al. 2007).

Other anti-plaque agents


Other agents that can be added to toothpaste to prevent plaque formation include chlorhexidine, stannous fluoride or a combination of zinc citrate, bromochlorophene and triglyceride. Unfortunately chlorhexidine is less useful, because it is inactivated by other common toothpaste components.

Anti-calculus agents


When plaque is not removed it can start to harden and mineralize to form supragingival calculus. One of the ways that this process can be stopped is by adding crystal growth inhibitors to toothpaste. Agents that have been suggested for this purpose include pyrophosphates, phosphonates, zinc salts, and a copolymer of methyl vinyl ether and maleic anhydrides (Davies et al., 2010).