Fluoride

When fluoride is taken internally during tooth formation, it becomes incorporated into the enamel (the outermost protective layer), making the tooth less prone to decay. Once a tooth has been formed, however, fluoride taken internally no longer has any effect on its structure. External treatments such as fluoridated toothpastes and rinses, though, do have an effect. Fluoride will often stop the progression of early decay and has been shown to prevent the formation of cavities on the roots of teeth. It does this by slowing down the demineralisation process of decay by actually making tooth enamel harder. In addition, it aids in speeding up the remineralisation process.

What is remineralisation and how does it work?

The process of tooth decay causes demineralisation or loss of minerals. With the aid of fluorides, minerals are incorporated back into the decayed region through remineralisation. Both the demineralisation and remineralisation processes are continuously ongoing. Basically, it's a tug of war between the two. When remineralisation overcomes the demineralisation process, decay can actually be reversed and the affected area restored to health. The remineralisation process also significantly increases the size of the enamel crystals. Larger crystals are more resistant to acid attack than the enamel you were born with.

Studies have shown that it takes about 3 years from the time a cavity begins until it is large enough to be detected in an X-ray. Therefore, even for those of you who may not have any radiographically detectable decay in your mouth, it's a good idea to consider fluoride as a means of prevention. Studies have also shown that low levels of fluorides (such as in toothpastes and rinses) are more effective than high fluoride concentrations at reversing early decay.

Can topical fluoride applications produce tooth mottling (pitting and discolouration)?

Tooth mottling is caused by excessive systemic use of fluorides during the period of tooth development, not by topical use. Like any nutrient, fluoride is beneficial in the proper amounts, but harmful in excessive amounts. Some geographical areas do not have fluoridated water. Other areas have naturally fluoridated water. Geographic locations in which the water supply is not naturally fluoridated have no more than the recommended level of fluoride (which is 0.7 to 1.2 ppm depending on climate) added to the water. Ingestion of water having a fluoride concentration of two to three times greater than the recommended level can produce white flecks and chalky opaque areas in your teeth. Consumption of water having a fluoride concentration of four times the recommended level can cause brown, pitted and corroded areas.

Other Causes of Enamel Discolouration

• Drug therapy given during tooth development (i.e., tetracycline during pregnancy can result in permanent staining of the child's teeth)
• Formation of an abscess from an infected baby tooth can lead to discolouration of the permanent tooth's crown
• Infection
• Trauma to baby teeth causing the damage to permanent dentition

Is Fluoride Safe?

There have been continuous studies carried out over the years on large sections of the population to determine if there are any adverse health effects from fluoride. There is no clinical evidence to suggest that fluoride in the recommended concentrations is anything but entirely safe.