Concerned about Fluoride

Dr. Phillips,

I am interested in your system for dental care but also very concerned on the topic of fluoride. Everywhere I turn there are negative arguments for use of all types of fluoride, whether it be ingested or topical. On your blog you state that you are against fluoridation of water, while being a proponent of surface treatment for teeth. With such abundant use of fluoride in your system, it seems that absorption through mucus membranes in the mouth would rival or even surpass the levels present in drinking water. Now I know that many chemicals may be beneficial in moderation while harmful in excess. Do you have any literature regarding this topic or any particular studies of interest worth looking at? Thank you.


Hi CG,

I am sorry to have taken so long to reply to your message. The subject of fluoride is complex and I wanted to find the time to give you a complete reply.

It is important to identify the kind of fluoride you are debating. I will not defend the fluoride used for water fluoridation. This is often a by-product of industry a silico-fluoride compound.

Sodium fluoride has been thoroughly tested for safety over many decades. This was the fluoride they originally planned to put in water supplies but it was too expensive and alternative compounds were found.

The exposure from Crest toothpaste would vary with the amount of paste dispensed. The paste will generally be in contact with the teeth during brushing, so I have no concern about mucus membrane absorption for a normal amount of paste used twice or three times daily. The toothpaste is then thoroughly rinsed off teeth with Listerine.

The final rinse with ACT is sodium fluoride. I agree that there is some exposure possible through mucous membranes, but research shows that we will excrete 98% of any fluoride absorbed. If you use half an ounce and spit out almost half an ounce then the concern would be from the residue left on teeth. I believe this is such a small amount it is of no concern.

To minimize this residue I encourage adults and children to spit out the final rinse several times (but not rinse it away because leaving a residue will prolong benefits).

I agree that in the perfect world with no dental disease and a perfect diet, no stress, no worries and no sickness we would not need fluoride for dental health. You may be lucky and have low risk for disease.

But if you have mouth acidity or lack saliva you will experience dental damage unless you have some protection. Dilute fluoride encourages natural repair and the formation of acid-resistant enamel.
I prefer the minute risk of exposure to a tiny amount of dilute fluoride residue than risk long-term exposure to dental restorations and treatment.

I hope this answers your questions. I will try to get some research papers on absorption of fluoride from toothpaste There was a study with young children who eat toothpaste and the researchers measured how much they absorbed. I think this is interesting although a different topic.

Ellie Phillips, DDS

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