Chapter 4: Oral Care – A Mouthful of Chemistry
Published:23 Sep 2020
E. Roberts and S. Mason, in Discovering Cosmetic Science, ed. S. Barton, A. Eastham, A. Isom, D. Mclaverty, and Y. L. Soong, The Royal Society of Chemistry, 2020, ch. 4, pp. 75-108.
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Hard enamel on the outside of teeth is supported by softer underlying dentine and pulp. Enamel is mostly composed of hydroxyapatite, formed from calcium and phosphate. Enamel can be weakened if the oral environment becomes too acidic (pH<5.5), but hydroxyapatite can be re-formed from salivary minerals. However, if this environment is too acidic for too long, enamel can be permanently lost, leading to tooth erosion and/or dentine hypersensitivity. Teeth, and gums, can also be affected by oral bacteria, especially in the form of plaque, which can lead to caries and gum disease, and by deposits of calculus. Fluoride toothpaste, delivered via a suitable toothbrush and brushing technique, can help with enamel remineralization and limit bacterial growth. Abrasives in toothpaste, along with chemical agents, can remove dental plaque and stained pellicle, the layer that forms over enamel. Additional ingredients, alongside different fluoride preparations, include those that can help with dentine hypersensitivity or gum disease, can limit calculus build-up or can whiten teeth. Formulation considerations must balance all of these ingredients and pack them in a toothpaste that not only works, with any product benefit claims being substantiated, but also tastes and feels good to use twice per day, every day.