Everything You Need To Know About Fluoride

Ready to learn the truth about fluoride? Your dentist, doctor (medical or homeopathic), or next door neighbor likely don’t know as much about it as they claim to. I’m going to cut through all the misinformation out there and give you the real story, based on the most current scientific evidence.

Why Is The Truth About Fluoride So Confusing?

Dentistry has been a bit behind the times on getting good research about the things that we dentists recommend. There is a ton of misinformation out there about fluoride. On one side you’ve got the people who claim that fluoride is the best thing since sliced bread while on the other side you’ve got people who believe fluoride is a giant government conspiracy for mind control. The truth actually lies somewhere in the middle (minus the mind control part). Dental schools currently teach a lot of the pro-fluoride misinformation while internet forums and homepathic doctors preach a lot of the anti-fluoride misinformation. It shocks me that you can barely find anyone with a reasonable and scientific explanation as to it’s risks and benefits when it comes to using it in dentistry.

I remember when I was in school that fluoride was put up on a pedestal as the best possible thing for our patients, with no discussion of the downsides to using it in various ways. None at all. They didn’t teach us about any of the latest scientific studies or even encourage us to look at them. All we were told was that the CDC called water fluoridation one of the 10 greatest public health achievements of the 20th century (we’ll get to that in a little bit), therefore water fluoridation was obviously a great thing… right?

What Is Fluoride?

First, what is fluoride? Fluoride is the negative ion of fluorine, the lightest halogen gas on the periodic table. Fluoride is a naturally occurring mineral found in many different sources around the world. It can be found in certain mineral deposits, usually in the form of calcium fluoride and is also found in varying concentrations in seawater and fresh groundwater. In seawater it is typically found at around 1 part per million (ppm) while in fresh groundwater it can range anywhere from 0.01 ppm to 0.3 ppm. Occasionally some fresh water sources have extremely high levels of fluoride (up to about 10 ppm). For comparison, most areas that fluoride their water try to keep it around 0.8-1.2ppm.

How Does Fluoride Work?

Fluoride, when applied in the correct form and concentration is known to strengthen teeth. So how does this work? Your tooth enamel is made up of small crystals of primarily hydroxyapatite. This crystals are packed very densely and there is an extremely small amount of water left (only about 4%). In comparison, your bones have about 30% water. When acid starts breaking down the crystals in your enamel, your body works to rebuild those crystals, if conditions are right. This is known as remineralization. If fluoride is present during this process it creates a slightly different crystal made up of fluoroapatite. These crystals tend to be larger and grow more quickly. They’re also less prone to being broken down by acid. This is why the presence of fluoride helps reduce cavities.

The History of Water Fluoridation

In the 19th and early 20th century, scientists noticed that some people had brown, mottled teeth that seemed to be more resistant to cavities. This staining was called the “Colorado Brown Stain”. Eventually scientists figured out that the people who developed this staining were people who were exposed to high levels of fluoride in their drinking water (naturally occuring). This brown staining is known today as fluorosis.

Over time they worked out what they thought were the optimal levels of fluoride in the drinking supply. These levels limited the occurrence of fluorosis but they thought it would also reduce cavities. The first test program was done in Grand Rapids Michigan in 1945 and quickly spread throughout the United States over the next 15 years. Approximately 2/3 of water supplies are fluoridated in the United States today.

Many other countries also fluoridate their water supplies or add fluoride to their salt.

Does Water Fluoridation Reduce Cavities?

Here is where it gets interesting. Early studies and evidence indicated significant reductions in occurrence of cavities. This was before fluoride containing toothpastes and mouthrinses were regularly used. Most of these studies were done before 1975 and weren’t terribly scientific. The Cochrane Collaboration did a review of all the available scientific literature out there and came to the conclusion that there is “very little evidence” proving the effectiveness of water fluoridation on cavity reduction. This doesn’t mean that it doesn’t work, but rather that there are literally no quality studies to make any conclusions from. Also, many of the studies were done in a time when oral health was treated very differently. New, quality studies would really need to be done to get an accurate picture of how effective it is.

There are, however, several other ways we can look at the effect of water fluoridation to see if it is actually effective today. The Cochrane Collaboration did another review about the effect of fluoride supplementation on cavity incidence. Fluoride supplementation is somewhat similar to water fluoridation in that children take a fluoride supplement that increases levels of fluoride in their whole body (as opposed to topical application of fluoride). The study found that fluoride supplements did decrease the levels of decay but only when compared to no fluoride use. When topical fluoride was used (as with fluoride toothpaste) there was no difference in cavity incidence between the two!

One study compared two neighboring towns in Canada. One removed fluoride from their water supply while the other left fluoride in it. Cavity rates actually went down in the town where fluoride was removed while the town that left fluoride in the water supply had the same levels of decay.

A 2007 article looked at decay rates in countries both with and without water fluoridation. All these countries had varying exposure of their populations to fluoride. The authors found that decay rates in all countries dropped significantly over the last 3 decades, whether or not the water supplies were fluoridated.

So what does all this tell us? Fluoridation of the water was likely effective in 1945 because there wasn’t widespread use of fluoride toothpaste or mouthrinses. Today, with the common use of fluoride toothpastes, professional fluoride varnish applications every 6-12 months, and fluoride mouthrinses, water fluoridation appears to be mostly ineffective. In addition to being mostly ineffective today, it also carries multiple risks that are just now starting to be known (we’ll cover these in a little bit).

Is Fluoride In Toothpaste Effective?

Compared to water fluoridation, fluoride in toothpaste is pretty straightforward. Most toothpastes contain between 1000-1500 parts per million of fluoride. Study after study has shown a benefit to topically using fluoride in toothpaste. The Cochrane Collaboration did a review on how well fluoride toothpaste works in reducing cavities in children and came to the conclusion that on average, consistent use of fluoride toothpaste over 1000 ppm reduces cavities by approximately 24%. This included 79 separate studies with around 73,000 total children studied. There really isn’t any doubt, whatsoever that fluoride in toothpaste is effective.

The Dangers of Fluoride

Systemic (fully body) fluoride exposure has several possible dangers.  Systemic fluoride exposure is most often the result of water fluoridation, high levels of naturally occurring fluoride in the water, and eating / swallowing toothpaste. Fortunately, topical exposure of your teeth to fluoride does not carry these same risks.

• Fluorosis – Fluorosis is the  most common side effect from excess fluoride exposure. Fluorosis shows up as white or brown spots on teeth. Lower levels of fluoride exposure cause minimal speckling while high levels cause an extreme brown mottling of the teeth that can cause significant cosmetic problems. It’s estimated that a water fluoride level of 0.7 ppm (lower than many municipal supplies) will cause fluorosis that is noticeable in 12% of people! Most water supplies are fluoridated to around 1 ppm, which likely carries even higher rates of fluorosis. I personally see patients with fluorosis all the time in my dental practice. I’ve seen higher and higher rates of children with fluorosis over the years.
• Underactive thyroid – Another recent study found a link between water fluoride levels over 0.3 ppm and higher rates of underactive thyroid glands (nearly 30% higher). This study was based in England and compared rates of hypothyroidism in populations with fluoridated water vs those that didn’t. The study included information from almost every general medical practice in England. While not a perfect study, it does bring up some very serious concerns about the possibility of thyroid disorders as related to fluoride exposure.
• ADHD – Another recent study showing possible harm from water fluoridation. Researchers compared data of average fluoride exposure from water fluoridation and compared it to rates of ADHD diagnoses. Those areas with higher levels of fluoride exposure, had higher levels of ADHD diagnoses, even after controlling for many other variables. As with the study on thyroid problems, this didn’t prove any causation but also brings up a possible serious complication of water fluoridation.
• Reduced IQ – It has been suspected for some time that fluoride can be slightly neurotoxic to the developing brain. Harvard recently completed a study along with researchers in China that studied IQ levels compared to fluoride levels in the water supply. On average IQ’s were 7 points lower in populations with fluoride in the water supply. The level of IQ impairment was directly related to the level of fluoride in the water system.
• Overdose – Overdoses from fluoride are pretty rare. The amount of fluoride needed to create an overdose are quite a bit more than you’d find in a tube of toothpaste, so even if you manage to eat the entire thing, you’re still probably fine. The danger of a fluoride overdose comes from the fact that fluoride combines with calcium and makes it unavailable to your body. Calcium is used for many different things in your body and low fluoride levels (hypocalcemia) can literally kill you.

The Centers for Disease Control (CDC) And The American Dental Association (ADA) Stance

Despite all this evidence, these two huge organizations still claim that there is no credible evidence of harm by water fluoridation and that they believe it is highly effective in reducing decay. Why is this? Honestly, I’m not quite sure. The scientific evidence is quite clear about the harms and limited effectiveness of water fluoridation today. These types of claims are one of the reasons why I started this website. There is a serious lack of real information out there about certain dental issues facing people today. Big organizations like these don’t change quickly and in the meantime can cause real harm.

My Fluoride Conclusions

My personal opinion is that fluoride should be removed from the water supply. It likely has little effect on decay rates today and has a high incidence of adverse effects compared to it’s effectiveness. Instead, there should be an emphasis on education about topical fluoride products such as toothpaste, mouthrinses, and professional applications of fluoride varnish.