What is Fluoride?
Fluoride fluoride fluoride…
Why is it that dentists love it so?
Is it good for your teeth?
What exactly does it do?
Do I need it?
Do I need more than I am currently getting?
What forms does it come in?
Is my water fluoridated?
There is a lot to discuss so let’s get started…
Fluoride is one of our truest allies in the fight against dental caries. It receives a lot of unfair bad press by anti-fluoride lobbyists who have various arguments on why it should be banned - I will touch on these later.
I understand their concern but, ask a dentist, any dentist, if they believe fluoride is a good thing and you will get an overwhelming response in favour of it. There’s a few holistic guys out there who may be adverse but get a 1000 strong group of dentists together and you’d be hard pressed to find the hands of those against it. Why? Because day in, day out we see the benefits it conveys on people’s teeth from the very young to the very old. In fact, the only people who it doesn’t help, are those we call edentulous- that is those with any teeth whatsoever!
What Evidence is there for the Effectiveness of Fluoride?
Aside from the clinical evidence we see every single day in the surgery, many scientific studies exist showing the effect fluoride has on enamel and on reducing dental decay.
A recent meta- analysis of the effectiveness of fluoride at reducing caries for fluoride gel treatments showed a 22 to 26% overall reduction in the amount of decay. That’s not to be sniffed at if you ask me. A meta-analysis by the way is a study of all the other studies.
Where is Fluoride found?
In our bodies- we have fluoride in:
Our blood
In our saliva
In crevicular fluid – This is a special clear (invisible to the naked eye) fluid produced by the cells in the gingival crevice- that’s the sulcus where your teeth and gums meet. It contains many protective elements and has anti-microbial properties to help protect your teeth.
In interstitial fluid– This is a bit hard to explain- it’s the fluid in-between your cells that helps to take away waste and provide nutrients for them to work effectively.
What is the Fluoride Concentration?
Fluoride concentrations are either shown in ppm (parts per million) or as a percentage.
The fluoride (F) percentage can be a little confusing since it is relative to the compound it’s in; the most common ones in toothpastes and mouthwashes are sodium fluoride (NaF), and acidulated phosphate fluoride (APF).
Hopefully this chart will help:
0.05 % fluoride (F)= 500 ppm
So what exactly does Fluoride do?
Fluoride can positively affect the teeth - both while they are developing; when they are fully formed and when they have erupted into the mouth.
What is the Effect of Fluoride Before Teeth Erupt?
Enamel is made up of many crystals arranged in a regular pattern; fluoride makes these crystals larger, denser, harder and more uniform. Imagine that your enamel is an army… this would be the equivalent of making each of your soldiers 10cm taller, giving them a few extra pounds of muscle, stronger shields and making sure they kept their shape when advancing- it would be so much harder for the enemy to penetrate.
Back in the real world, that means if the enamel layer of your tooth is formed in the presence of fluoride, it becomes more resistant to acid attack and ultimately dental caries.
What is the Effect of Fluoride After Teeth Erupt?
When teeth first erupt into the mouth, the enamel is at its least mature and most vulnerable to problems- the soldiers are younger, weaker and less experienced. The benefit of fluoride at this time is greatest. So what does fluoride actually do? This is a question I often get asked.
To understand this clearly, you need to understand a little about plaque, and how dental caries is formed. . It will also help if you know a bit about the enamel layer of the tooth. We are going to get a bit scientific here so bear with me… all will become clear. The simple points are in bold followed by the explanations in case you are curious.
Fluoride is great for our teeth because it:
Reduces the amount of plaque (our enemy) - It slows down the rate at which the bacteria in plaque are able to reproduce and therefore limits their growth.
Reduces the amount of acid that plaque produces – It does this by interfering with a key part of their metabolism called glycolysis, so they cannot break down sugars into acid as effectively.
Makes plaque less sticky – by interfering with its sticky protective layer (extracellular polysaccharide matrix), so it is more easily removed by saliva, rinsing and tooth brushing.
Stops demineralisation and promotes remineralisation of early enamel caries.
Makes enamel harder and less susceptible to acid attack and dental caries.
Fluoride conveys more of these benefits in easy to reach areas, such as the smooth surfaces of your teeth rather than the complex patterns (pits and fissures) on the biting surfaces of your molars.
How Exactly does Fluoride Work?
The basics:
Enamel, the hardest substance in the body is made up of crystals called hydroxyapatite crystals or HAP for short. Fluoride can get incorporated into the enamel to form a new crystal called FAP or fluoruohydroxiapetite. Enamel made with this is much stronger and more resistant to demineralization and dental caries.
The science:
HAP to FAP
Hydroxyapatite crystals are packed tightly together to form a regular solid structure called a lattice. The enamel lattice contains hydroxy ions (OH-). Fluoride (F-) has the same negative charge and can replace the hydroxy ion to form the more acid resistant crystal FAP, by a process known as iso-ionic exchange. It’s basically like a substitution on the footy field where you replacing a current player with a better player.
Fluoride reservoir If the outside layer of enamel has high concentrations of fluoride, calcium fluoride (CaF2) will form on the surface- the calcium comes from saliva. When this is exposed to acid, this calcium fluoride becomes negatively charged, forming an ion CAF2- which diffuses into the enamel to make FAP crystals, thus increasing the strength and resistance of the enamel.
Remineralisation Fluoride in saliva (even at low concentrations) helps encourage remineralisation by forcing calcium and phosphate out of saliva onto the tooth. The higher the pH of saliva, the greater the remineralisation that occurs.
But isn’t Fluoride Toxic?
The safety of water fluoridation still seems to be a question on some people’s lips despite the failure of many studies (of both natural and artificially enhanced fluoridated water) to demonstrate any harmful effects at 1ppm.
There was a landmark court case in Edinburgh in Scotland in 1983 which saw a judgement passed in the favour of the safety and usefulness of fluoride- an opinion backed by numerous government services and a systematic review of all the studies carried out by New York University.
If an excess of pretty much any chemical is taken, it can be toxic and fluoride is no exception. I guess the reason fluoride is contentious is because we add it to lots of things, which theoretically would increase the risk.
There are many elements found naturally in water that would be toxic in high doses; chlorine, sodium, calcium, magnesium, potassium and iron to name a few. And this is not considering the chemicals that get into our water supplies from various industrial processes. The pesticides and chemicals used in agriculture are far more of a concern to me personally. Have a read of this wiki page on water pollution if you want to scare yourself with all the rubbish that can get into our water supplies.
To reach a level where a child would need to go to hospital, 5mg of fluoride per kilogram of body weight is needed. That would mean a 5 year old (say they weigh an average of 20kg) would have to swallow:
10ml Mouthwash (0.05% F) - as it contains 10mg/ml
5ml of a Varnish (2.2%F) -as it contains 22mg/ml
100 2.2mg tablets (NaF) -as they contain 1mg fluoride
35 drops of fluoride -as it contains 0.5mg/ 1 ml contains ( 1 drop = 0.5ml )
Over a large tube of standard (0.8%) fluoride toothpaste.
This highlights the importance of storing fluoride safely away from little hands.
If this was to happen, you should go immediately to hospital to have it removed from their stomach, as this is where the fluoride is mostly broken down and absorbed. The doctors most often begin this process by giving an emetic to try to induce vomiting. If a child has swallowed less than 5mg- a large amount of milk can help to neutralize the fluoride. If you are concerned at all, call your doctor or Accident and Emergency.
There is no evidence to suggest that areas supplied by fluoridated water experience higher cancer rates than normal.
What is Fluorosis?
Fluorosis is a white mottling or patchy white appearance on the teeth, which happens when an excessive amount of fluoride has been taken in over a long period; during the time when the enamel was being formed.
The biggest risk to the adult front teeth is between the ages of 2 and 5 years, when the teeth are developing underneath the gum- out of sight. In the presence of too much fluoride, the outer part of enamel doesn’t form properly and in severe cases this causes pitting and discolouration of the enamel.
Most fluorosis occurs in areas where fluoride is found naturally in very high concentrations in the water supply, but it could also result from eating toothpaste or taking supplements when living in an area with fluoridated water.
For this reason, it’s important that parents supervise their children when brushing and limit the brushing to two proper sessions a day. Brushing with fluoridated toothpaste in naturally high fluoride areas, is likely to have very little additional effect and should be continued.
In one study by Houwink and Wagg 1979, it was shown that children who used fluoride toothpastes at twice the normal concentration, had less developmental defects than those who used a fluoride free toothpaste.
In a nutshell: General points to remember!
Spit out toothpaste, don’t rinse
If fluoride in water is low- supplements are useful until the child starts using fluoride toothpaste
If fluoride in water is over 0.7ppm- no additional systemic fluoride is needed
Children should only use children’s toothpaste (low fluoride) up to the age of six
High caries rate children and adults benefit greatly from extra fluoride- the advantages outweigh the small risk of mottling
Water fluoridation is a good thing
Newly erupting teeth benefit the most from fluoride.
All information found in this post is credited to Jamie Workman and can be found on his website www.jamiethedentist.com
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