Fluoride is an environmental contaminant (WHO), however it is considered to be beneficial to teeth when taken regularly in small doses.
Method of Action:
The main method of action of fluoride is to slow down tooth decay by helping minerals which dissolve from the enamel during cavity formation (calcium and phosphate), to go back into the enamel (remineralisation). This can occur when the levels of fluoride in the saliva are greatly elevated from the normal baseline levels. This happens for 1-3 hours after brushing with fluoride toothpaste, or using a fluoride mouth rinse (both containing about 1,000 – 1,500 parts per million F)
Fluoride is incorporated in some dental materials such as restoratives and fluoride varnish, which dentists use when clinically indicated to fight or prevent tooth decay. These work by applying high F levels in specific, at risk areas.
Sources of fluoride
In addition to being present in toothpaste, mouth rinses and dental treatments, fluoride is added to Wellington’s drinking water and is present in many foods and beverages, particularly tea and beer.
Average Daily Fluoride Dose
The NZ Ministry of Health has no data on the total amount of fluoride ingested by individuals on a daily basis.
Estimates have been made (ESR2009), which indicate that in New Zealand, children and infants, as well as some adult groups, are getting high enough levels of fluoride to potentially harm their health. Recent research strongly suggests that fluoride levels can affect the brain development of young children, including in utero, as F effectively crosses the placenta in pregnant women(Grandjean 2014, Bashash 2017)
Fluoride overdose has also been linked to endocrine disorders, particularly thyroid disease (NRC review 2006, Peckham 2015)
Responsible Fluoride Use, my opinion
Therapeutic professionally applied, targeted fluoride application is a useful tool in dentistry (although there are other remineralising alternatives now available)
Fluoride toothpaste should be minimally applied (a pea size amount in adults, and a grain of rice size in children) and used no more than twice a day. Young children swallow about 70% of the toothpaste and adults about 30%.
Fluoride mouth rinses are an alternative to tooth brushing,and result in the same amount of fluoride ingestion. They should be used as an alternative, not in addition to, tooth brushing.
Fluoride should be avoided in pregnancy and early childhood.
Unfluoridated water should be used for making up baby formula.
Reducing Uncontrolled Doses of fluoride
People who want to reduce their fluoride intake levels can take the following advice:
Fluoridated tap water can be avoided by using bottled water. Effective fluoride filters are expensive and may remove essential minerals.
F toothpaste can be substituted with baking soda toothpaste (eg Red Seal). Raising alkalinity of saliva has a similar effect in reducing cavities as does increasing fluoride levels.
Control tea drinking, especially black leaf teas
Better teeth without fluoride
Tooth decay is caused by sugar consumption and lack of oral hygiene, not by lack of fluoride. Fluoride simply helps to slow down the progress of early cavities.
For people on low sugar diets, who clean their teeth regularly, fluoride is of minimal or no benefit.
The acidity of saliva is also an important factor, with alkaline saliva being less cariogenic. Cleaning the teeth with baking soda containing toothpaste is therefore advantageous.