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01/23/2008
Pros and Cons of Fluoride
Every so often I read an article or news report on the overuse of
various medical procedures and the costs to our healthcare
system. Last week I suspected that this was indeed the situation
in the case of my wife who, as I mentioned last week, fell and
ended up in the hospital with severe pain in her chest and back.
Two sets of X-rays showed no fractures and the assumption was
that her pain was due to bruised ribs and/or other trauma. After
being readmitted to the hospital, a new doctor took over her case.
She ordered a CTscan, which at the time I thought might involve
more X-ray exposure than necessary. However, the CTscan
showed a compression fracture in a vertebra in the spine! My
wife was fitted with a brace and is now in a rehabilitation center,
hoping that the fracture will heal without surgery.
With my life being so medically oriented these days, I was
attracted by an article by Dan Fagin titled “Second Thoughts
about Fluoride” in the January 2008 Scientific American.
Growing up in the 1930s and 1940s, as did most of my
schoolmates I had my share of cavities and dreaded those visits
to the dentist. Until I was in my forties, I never had any
Novocain when I received those mercury amalgam fillings.
I didn’t know that near my birthplace of Denver, in Colorado
Springs in the early 1900s, a dentist named Frederick McKay
was intrigued by reports of a staining and mottling of the teeth in
children born in Colorado Springs. The phenomenon went by
the name of Colorado Brown Stain. McKay noted that those
children who moved into Colorado Springs did not show signs of
the brown stain and he suspected that there was something in the
water that affected the enamel of the teeth that had not yet
erupted in the native born children. It wasn’t until 1930 that
McKay, following up reports of Colorado Brown Stain in
children in a town in Arkansas, spurred an analysis of the town’s
water supply. The analysis, performed by chemist H. V.
Churchill, revealed a relatively high level of naturally occurring
fluoride. Colorado Brown Stain became a disease known as
dental fluorosis.
Fast forward to 1945. It was that year that Grand Rapids,
Michigan took to heart a recommendation by Henry Trendley
Dean, head of the dental hygiene unit at the National Institute
(now Institutes) of Health. Dean had come to the conclusion
that, at levels of less than 1 milligram of fluoride per liter, there
would be little risk to health and that, based on the work of
McKay and Churchill, there should be a positive effect on dental
health if fluoride were added to the water supply. (In those
communities where the Colorado Brown Stain was prevalent, the
fluoride concentrations were around 2.5 milligrams per liter or
higher.) By the 1950s the push to add fluorides had expanded to
hundreds of communities. I remember that there were heated
objections from various groups and individuals concerned about
adverse health effects as well as about enforced medication of
entire communities.
However, fluoridation of public water supplies became the norm
and today over half of us in the USA are drinking fluoridated
water. In addition, fluoridated toothpastes were introduced and I
personally embraced fluoridated Crest, hoping to cut down on
those pesky dental visits. Today, one is bombarded by
commercials and ads for whitening teeth and I look at my 80-
year-old teeth and wonder if my failure to match those pearly
white ones in the ads is due to overuse of fluorides. Actually,
after reading the Scientific American article, I find there may be
more serious concerns than having white teeth.
Let’s look at the enamel of a tooth. It is composed primarily of a
mineral known as hydroxylapatite, composed of molecules of a
particular form of calcium phosphate containing a hydroxyl (OH)
group. One mode of tooth decay occurs when particles of food
trapped between teeth react with bacteria, a process that forms
lactic acid. There are two competing reactions going on. The
lactic acid dissolves the enamel while calcium ions and
phosphate ions present in saliva tend to form hydroxylapatite,
effectively remineralizing the enamel. If the lactic acid is faster
at dissolving the enamel than the remineralization, a cavity
forms.
When fluoride is present or is applied, some of the fluorine
atoms replace some of the hydroxyl groups, forming the
compound fluoroapatite. This compound is more resistant to the
lactic acid and in addition catalyzes the deposition of calcium
and phosphate, thus speeding up the remineralization process. In
so doing, the fluoride hinders tooth decay. This is all well and
good but what happens if a young child ingests too much
fluoride?
The excess fluoride blocks the removal of proteins that control
the formation of hydroxylapatite and, when these proteins hang
around too long, staining and uneven coloration can result as
well as pitting or other uneven tooth growth. A critical period in
enamel growth in preemergent teeth is the toddler stage.
Fluoride consumption may stay high in toddlers partly because
toddlers have apparently been found to swallow more than half
their toothpaste despite being told to spit it out!
Sources other than toothpaste, such as soft drinks and juice
drinks may contain significant amounts of fluoride, often
introduced from water added during processing. Indeed, those
who drink a lot of water can exceed the level of fluoride optimal
for dental health. Colorado Brown Stain or fluorosis isn’t
considered a health hazard but stained or irregularly shaped teeth
aren’t exactly great for one’s self esteem. However, teeth are
one thing; bones are another. Fluoride that doesn’t get excreted
or incorporated into teeth will almost certainly end up in bone.
Here’s where things get a bit dicey. It seems that large amounts
of fluoride spur the formation of osteoblasts, the cells that
stimulate the building of bone. With all the talk about
osteoporosis and loss of bone on aging, you might say that the
extra fluoride is doing a good thing, producing more bone.
Unfortunately, the fluoride produces more bone, but of a
different structure than normal bone and this fluoride-induced
bone is weaker than normal bone, increasing the risk of fracture!
There is also concern that, by stimulating excess production of
osteoblasts, the excess fluoride might be causing oteosarcoma,
the most common form of bone cancer. A vigorously disputed
paper involving rats suggest a link but other researchers are
highly critical of the study. Equally controversial are studies
suggesting links between fluoride and hyperactivity, lower IQ
and abnormal thyroid activity.
At present, there’s a renewal of the controversy of some six
decades ago when fluoridation of water supplies was first
introduced. Today, the antifluoridationists are at one extreme
while at the other extreme there are those who feel, as did one
surgeon general, that fluoridation is one of the ten greatest
achievements of the twentieth century and should be expanded to
embrace even more water supplies. Who knows how and when,
if ever, this controversy will be resolved?
Oh well, being well beyond the toddler stage, I’ll continue to use
my fluoridated toothpaste. Hey, I do spit it out.
Allen F. Bortrum
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