NAS Report: Comment 2 - Delayed Eruption

Comments on the 2006 NAS/NRC report

NAS Report: Comment 2 - Delayed Eruption

Postby admin » Mon Apr 03, 2006 4:38 am

Comments on the NAS/NRC Report: Fluoride in Drinking Water: A Scientific Review of EPA's Standards

On page 126 of the Report (Chapter 4):

"Questions have also been raised about the possibility that fluoride may delay eruption of permanent teeth (Kunzel 1976; Virtanen et al.1994; Leroy et al. 2003). The hypothesized mechanisms for this effect include prolonged retention of primary teeth due to caries prevention and thickening of the bone around the emerging teeth (Kunzel 1976). However, no systematic studies of tooth eruption have been carried out in communities exposed to fluoride at 2 to 4 mg/L in drinking water. Delayed eruption could affect caries scoring for different age groups."


This is actually quite laughable. Here the panel is looking at severe dental fluorosis, declaring it - thankfully! - not a cosmetic effect, yet apparently does not understand that the condition is tied directly to the eruption of teeth. Dental fluorosis gets more severe the longer it takes for the tooth to erupt (Larson et al. 1997; Van Palenstein et al. 1997).

No mention is made of the "hypothesis" that the eruption of teeth might be caused by interference with thyroid hormone activity. For 100 years it has been known that thyroid status controls tooth eruption!

Edwin Short conducted a study in 1944, comparing eruption rates in children living in US areas with varying amounts of fluoride in the drinking water. Besides the fact that the author committed numerous errors in his analysis, i.e. by pooling all children together instead of sorting by gender, he was forced to conclude:

"Public water supplies containing fluorides in concentration of 2.6 parts per million appear to be associated with delayed permanent tooth eruption in children 12 years of age who have been continuously exposed to the water supply."
(It is indeed perplexing that this study is mentioned in relation to tooth eruption in Chapter 8, Endocrine Effects, but not here in Chapter 4...)

Page 9 of the NAS Report states:

"More research is needed on the relation between fluoride exposure and dentin fluorosis and delayed tooth eruption patterns."

It seems to us that what is needed more is someone who actually understands what they are reading. There certainly is plenty of research...

The PFPC has a large database of many papers addressing the delayed eruption of teeth, a process directly controlled by thyroid hormone, at: ... ption.html
(Members only)

Bob & Wendy

Larsen MJ, Kirkegaard E, Poulsen S - "Patterns of dental fluorosis in a European country in relation to the fluoride concentration
of drinking water." J Dent Res 66(1):10-2 (1987)

Short EM - "Domestic water and dental caries. VI. The relation of fluoride domestic waters to permanent tooth eruption" J Dent Res 23:247-255 (1944)

van Palenstein, Helderman WH, Mabelya L, van't Hof MA, Konig KG - “Two types of intraoral distribution of fluorotic enamel” Community Dent Oral Epidemiol 25(3):251-5 (1997)
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