Toothpaste

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Toothpaste

CHEM1022

Amy Abrahamson, Andrea Buhr, W. Julie Gicheru, Matt Giles, Jacob Haapala

Figure 1. Structure of a tooth. Image used from Kathryn C. Morley ([2]).

With all of the different types of toothpaste available today, one must wonder, what is the difference? What type of toothpaste cleans teeth the best, and how does it clean teeth? Two important ingredients in toothpaste are fluoride and sodium lauryl sulfate. Flouride is the most important ingredient for keeping teeth clean. Sodium lauryl sulfate creates a soapy foam that aids in the removal of plaque and build-up. These two ingredients are found in various toothpastes including whiteners, tartar controllers, desensitizers, gels, and pastes.

One important component of toothpaste is fluoride. This mineral is an essential part to keeping teeth healthy. There are three main methods that enable fluoride to keep our teeth strong. The first is that fluoride helps with the remineralization of teeth. Teeth cannot be remineralized by digestible supplements, only by substances like fluorinated water, toothpaste and saliva (Morley 1). Remineralization happens when the lattice structure of the tooth’s surface has Ca and PO₄ ions added back into the structure (Morley 1). This process occurs by making the concentration of calcium increase in the plaque fluid. By using the common ion effect, the concentration assists in forming calcium-phosphate-fluorine salts, which become embedded in the surface of the enamel and decrease demineralization (Whitford 1).

The second way fluoride keeps teeth healthy is by preventing or slowing demineralization, which causes tooth decay. Demineralization happens when the lattice structure of the tooth\’s surface has Ca and PO₄ ions removed from the structure (Morley 1). As mentioned above, fluoride adds salts to the surface of the enamel. This is done by substituting a fluorine atom in for the hydroxyl ion to form the compound hydroxyfluorapatite (Ca₁₀(Po₄)₆(OH)₂) or fluorapatite (Ca₁₀(Po₄)₆(OH)F) (see Figure 2) (Whitford 1). These two substances are not as soluble as hydroxyapatite in acid, so the tooth is more resistant to decay (Whitford 1).

Structure of hydroxyapatite. Image used from Kathryn C. Morley ([1]).

The final way that fluoride is helpful to teeth is by blocking the amount of acid that is produced from fermentable sugars by bacterial enzymes. Fluoride also inhibits the membrane transport of the sugars into the cell, by hindering the phosphotransferase system (Whitford 1). Acids are what cause demineralization by removing the Ca and PO₄ ions (Morley 5). Furthermore, another important chemical property of toothpaste is a detergent known as sodium lauryl sulfate (SLS). "Sodium lauryl sulfate is predominantly used as a foaming agent in shampoos and mass-market toothpastes," says Gary Verigin, DDS, a member of the Holistic Dental Association in Escalon, California (qtd. in Francisco). This ingredient is classified as soap and causes toothpaste to foam in the mouth and help fight against plaque (Francisco). Brushing one’s teeth at least twice a day can help prevent a number of oral infections and bacterial growth. By scrubbing toothpaste against teeth, foam is produced, and the motion triggers the detergent SLS (Sznopek). In this case, the neutralization of acid is a chemical process which eliminates plaque and other formations of sugar deposits (Sznopek). By producing foam, the toothpaste is able to infiltrate the plaque and loosen the film on the exterior of the teeth (Sznopek). Essentially, bacteria are less likely to attack the mouth after this point in one\’s daily hygiene.