The two most controversial topics in dentistry are Fluoride and "Silver Fillings" (amalgam). Fluoride is a compound of fluorine, which is a naturally occurring element that is a gas at typical temperatures on earth. Silver fillings are a compound that is the combination of metals consisting of elemental mercury, silver, tin and copper.

      The reason for the controversy is that both fluorine and mercury are toxic to human beings. Both of these elements, in excess, can cause death to people. But it is important to understand the chemistry of these elements to appreciate how these highly reactive elements can be used to produce compounds that can be beneficial to human beings.

      As an illustration, we can use water, the most abundant substance on earth. It is the chemical combination of hydrogen and oxygen.  The hydrogen bomb was used in the Second World War to completely obliterate two cities in Japan.  Have you ever seen a sign that said: oxygen in use, no smoking? This is because hydrogen and oxygen are highly reactive elements.

The Great Debate

      Do you remember Play-Doh? What happens when you mix blue Play-Doh with yellow Play-Doh? It turns green. Is there any way after you mixed the two colors together, that you can get back the blue or yellow color? The answer is no. The blue and the yellow Play-Doh can be compared to elements. The green can be compared to a compound.

      Once the colors join, they cannot be separated. The same thing with fluorine and mercury. Once they combine with something else, they are no longer the element they were. They are rendered harmless, just like hydrogen and oxygen are rendered harmless when they join together to form water.

Once fluorine combines with calcium, and mercury combines with silver, tin and copper, they are rendered harmless. However, not everyone believes this. Scientific studies have proven the fact that fluoride and amalgam (silver fillings), do not have any detrimental effects on the human body.

Fluoride has been shown to prevent decay of the teeth since the 1950's. Too much fluoride will result in the weakening of the teeth. Just like sugar is needed for the proper functioning of every cell, too much sugar can lead to diabetes. Mercury can be found at high levels in foods such as shrimp and shellfish (clams, mussels, oysters).

      So what does this all mean? Too much of anything is generally bad for the human body. However, taking advantage of the properties of chemistry with respect to our health can benefit our bodies. Fluoride in the form of toothpaste and mouth rinses will protect our teeth. Just don't swallow them! Fluoride can rebuild weakened enamel and significantly reduce sensitivity associated with temperature, sweets and touch of the teeth.

      I have seen amalgam fillings that have lasted 40 years. The last amalgam I placed was in 1996. But it wasn't because of mercury. It was because dentists now have a superior material that replaces amalgam. This is the composite material that is tooth colored. 

      Composite is very similar to a tooth in its ability to be used like the enamel of the teeth. Because it is bonded to the existing tooth structure, it literally becomes part of the tooth. Amalgam just filled in the space that decay destroyed. While composite is an amazing advance in dentistry, it still cannot take the place of a crown if a tooth has been significantly compromised by decay or wear because of bruxism. Next month we will touch on that subject - stay tuned.

      In the meantime, just like we all need water to be healthy, we have helpful aides to help keep our oral cavity healthy.

Happy smiles begin with healthy choices!