Friday, 29 April 2011

Toothpaste, a fluoride menace?

It has been a while since my last article, but The Toxicologist Today is back with brand new subjects ready for spitting. I have a mouth full of foamy fluoride for those who have decided to visit the blog today, as the subject is Toothpaste, more precisely the fluoride present in the composition of any random toothpaste, gel and even sometimes, mouthwash. 

The increasing risk of contamination in children due to ingestion of fluoride makes one sound the red alert for an agent that is not yet a menace, but if unsupervised can become an issue for hospitalization and, therefore, medical treatment. In the past several authors alerted for the fact that children were becoming more exposed to inappropriate utilisation of toothpaste can represent a menace for children's health. In 1972, a Scottish research group assessed average ingestion of toothpaste in children aged between 3 and 6 years old, using a gravimetric technique amongst other evaluations, and concluded that the amount of apparently swallowed toothpaste during brushing  averaged 0.5g and 1.16g for 70% of the subjects [1]. The technique was somewhat unrevealing and to a certain extant unreliable, but as other techniques have proven, toothpaste had been inadvertently ingested. 19 years later Augenstein et al (1991) reviewed 87 cases studied in children younger than 12 years old reported to the Rocky Mountain Poison Center between the 1st of January and the 31st of December of 1986 [2]. The research revealed that in 96.5% of the retrospectively reviewed cases accidental ingestion of dental fluoride products occurred in children 8 months to 6 years old. Immediately two groups are stressed out from this particular investigation: 1) Fluoride products in the home, and 2) unsupervised children between 8 and 72 months old. 30% of the reviewed cases had symptoms of gastrointestinal upset, nausea, vomiting, abdominal pain and even diarrhoea [2]. 

This was back in the dying decade of the 20th century. 20 years have passed but two things remain the same, children are still children with all their innocence and ignorance, and fluoride is still toxic and fairly available for accidental ingestion.  Compared to the latter half of the 19th century and the first 50 years of the 20th century, the occurrence of fatal accidents involving ingestion of fluoride compounds declined abruptally, but the number of reported cases has, unfortunately, increased [3]. I believe that these reported facts, through time, describe an unchanged tendency for children to be exposed to the dangers of accidental fluoride ingestion as part of their necessary daily oral hygiene. But how come something advertised as so important as fluoride-based toothpaste can become a menace to children's health? And what is the real profile of the dangers associated to accidental fluoride ingestion? 

Fluoride is a naturally found element that can be found in water (for domestic consumption) and food we buy in the supermarket. Absorbed fluoride is used by our cells to enhance the quality of our enamel, and topical fluoride applied on the surface of our teeth enamel fortify the crystal network that composes enamel, thus making it more resistant to acids to which teeth are daily exposed to, due to our modern diets, affecting the structure of enamel (the following image was taken from source A and represents a rat's enamel structure).

Each year there are numerous reports of cases related to excessive fluoride ingestion flooding the northern american poison centres. The effects can be produced with as little as 0.1 to 0.3mg/Kg to trigger gastrointestinal disarray, and 5mg/Kg to kill the individual [4]. The biochemical chain of events by which fluoride can undermine one's health is the following: a) ingested fluoride becomes hydrofluoric acid (corrosive for the gastrointestinal epithelial lining) in the stomach, b) because biased assessments from parents can conduct to difficult understanding of the symptoms, sometimes when children reach the hospital they are already suffering of nausea (displayed by 97% of the cases), vomiting (68%), diarrhoea (65%) and abdominal cramps (53%) [5]. In addition, fluoride toxicity can cause bone deformation in children and can alter the appearance of children's teeth during teeth development. 

Lately several groups have been dwelling on rules to prohibit usage of fluoride by the industry operating in the context of health products. 

"Anti-fluoride campaigners have also pointed to isolated studies and anecdotal evidence indicating that exposure to fluoride may be linked to thyroid problems, bone cancers and hip fractures. “The danger with toothpaste is that large amounts are easily swallowed,” says Lees. “This is made worse for children by manufacturers who give it tempting flavours.” But Lees is a lone voice. Most dentists are convinced that fluoride is good for teeth and that there is no evidence that it does harm — apart from the occasional case of cosmetic dental fluorosis. They point out that in the ten years after fluoride toothpastes were introduced in 1973, dental disease in children fell so dramatically that some dentistry schools had to be closed." [4]

So what to expect from hyper flavoured products appealing to the consumer's most irresistible cravings, like BACON!

If you'd like to know the minimum single dose producing acute toxicity in fluoridated toothpaste, please check the next image. As a post scriptum I checked the back of my Aquafresh Fresh & Minty toothpaste and the info there reads 1.45g/L fluoride, so I think I am all right even if I decide to go all hungry on several tubes. That's it for today, in hope this article has promoted a good comeback to The Toxicologist Today. See you very very very soon for some weird poisonous animals!!! Until then, spread the news!

[1] Hargreaves, J. A., Ingram, G. S., Wagg, B. J. (1972). "A gravimetric study of the ingestion of toothpasteby children". Caries research, 6(3). pp. unknown.

[2] Augenstein, W. L, Spoerke, D. G., Kulig, K. W., Hall. A. H., Hall, P. K., Riggs, B. S., Saadi, M. E., Rumack, B. H. (1991). "Fluoride ingestion in children: A review of 87 cases". Pediatrics, 88(5), pp. 907-912.

[3] Whitford, G. M. (1992). "Acute and Chronic Fluoride Toxicity". Journal of Dental Research, 71(5), pp. 1249-1254.

[4] Fluoride Action Network, Minimum dose of fluoride producing acute toxicity,, last visited on the 29th of April 2011, last update unknown.

[5] Penman, A. D., Brackin B. T., Embrey, R. (1997). "Outbreak of acute fluoride poisoning caused by a fluoride overfeed". Mississippi, 1993. Public Health Reports 112:403-9.

[A] University of Florida, Biometrics Laboratory,, last visited on the 29th of April 2011, last update on the 22nd of February 2010.

3rd image taken from [A]

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