How does fluoride prevent cavities?
The Protective Benefits of Fluoride
Fluoride protects teeth by driving the remineralisation process and making the tooth’s surface harder and more acid resistant.
Fluoride drives tooth remineralisation
Tooth decay is caused by the long-term demineralisation of the tooth. In simple terms, the enamel (outer protective coating of the tooth) is made up predominantly of phosphate and calcium. Acid in the mouth (caused by bacteria living in plaque converting sugars to acids or from acidic foods) can dissolve the enamel (demineralisation) and over time cause decay and cavities to form.
Fortunately, the demineralisation process is naturally reversed with a process called remineralisation. The essential minerals lost in demineralisation are replaced in the tooth. This process can, however, require a boost. Toothpaste and more specifically remineralising toothpaste can assist the natural process, by providing essential calcium, high-levels of phosphate and fluoride.
The fluoride drives the rate of remineralisation and the extent of remineralisation, ie how fast and how much. Fluoride gets absorbed onto the tooth’s surface, attracting other minerals such as calcium and phosphate to the demineralised area.
Fluoride hardens teeth
When the tooth is remineralised in the presence of therapeutic levels of fluoride, the replacement mineral that is formed is called fluorapatite. In nature, fluorapatite is found in sharks teeth. Fluorapatite is harder and more acid resistant than the enamel’s hydroxyapatite and carbonated hydroxyapatite. With fluorapatite being able to resist pH levels down to 4.5 compared to 5.5 for hydroxyapatite. ( pH 7 is neutral, the lower the pH the more acidic).
Fluoride and its benefits are one of dentistry’s most researched areas. Recent breakthroughs in technology have however changed the delivery mechanism for fluoride. Traditionally, fluoride disappears from the mouth quite rapidly post washing. To overcome this rapid decline in available fluoride, toothpaste contains relatively high levels of fluoride at around 1450 ppm (parts per million). At this level, the fluoride stays above therapeutic levels for about 100 minutes. Most people wash their teeth twice per day, this means that therapeutic levels of fluoride are only available for around 3.5 hours each day.
A breakthrough in fluoride performance
New technology developed at the Queen Mary’s University of London has changed the delivery mechanism. Instead of using high doses of fluoride to extend the therapeutic window, the fluoride is released slowly into the mouth.
The slow release mechanism can deliver therapeutic levels of fluoride across the whole day with twice per day use. In turn delivering significant performance gains over regular toothpaste. This new technology has made its debut in a new toothpaste called BioMinF. BioMinF delivers high levels of anti-decay (anti-caries) benefits with high levels of remineralisation. Studies show BioMinF outperforms many market leading brands whilst only using less than 600 ppm of fluoride. BioMinF does all this whilst using almost 60% less fluoride than regular toothpaste.
Benefits of fluorapatite
Fluorapatite is more resistant to acid than tooth enamel (hydroxyapatite) and hence gives greater protection against acid attack. Conventional toothpaste introduces fluoride during brushing, however, the fluoride rapidly diminishes at an exponential rate.
Bioactive glasses dissolve under acidic conditions to protect teeth.
When faced with an acid challenge as a result of bacteria metabolising sugars or drinking an acidic beverage the glass dissolves. Quickly raising the pH and releasing calcium phosphate and fluoride ions to minimise the acid dissolution of the enamel apatite crystals.
Enamel, Demineralisation and Remineralisation
The outer layer of the tooth is known as the enamel, it is the hardest substance in the human body and because of this provides good resistance to abrasion and wear.