Fillings replace decayed tooth tissue. If even small amounts of decay are left in place, they’ll continue to spread and eventually the tooth will need a crown, a “root canal”, or extraction. Even then, untreated decay will spread further, into the gums and bone, and into the blood circulation, which will carry it to all other parts of the body. In this way dental health can directly impair general health.

So fillings are essential for most of us. Dentists use several different types of materials to fill cavities:
· White dental composite – consisting of a blend of glass or quartz filler and resin. This produces tooth-colored fillings for small-to-medium cavities and is good when the teeth are used for moderate chewing.
· Porcelain – a pearly white dental ceramic which reacts to light in a way similar to tooth enamel, and makes beautiful, durable fillings anywhere in the mouth
· Metal amalgam – a mix of 50% mercury, with smaller amounts of tin, zinc, silver and copper. It has been used for about 150 years but recently has come under attack.

What is mercury?
It’s a basic chemical element, which means it can’t be broken down into any components. It’s also a heavy metal like lead, and therefore harmful to our bodies. It occurs naturally on planet Earth and can take several forms. It can exist by itself as elemental mercury, or combine with other substances in organic or inorganic compounds. Traditionally it was used in thermometers but that is now banned in many states and in the European Union. When it’s exposed to the air, it gives off mercury vapor, more when the air is warmer. It is known to harm the nervous system, so that someone with mercury poisoning loses control of their movements.

The Amalgam Controversy

Probably most of us have had amalgam fillings at some point, and may still have them. In recent years, as porcelain and white dental composite have grown more popular, along with cosmetic dentistry , discussion has evolved as to whether the mercury in amalgam is a health hazard. It has been linked to neurological disorders, birth defects and mental disease.

Those who maintain it is harmful are concerned about the mercury vapor which is continually rising from the amalgam whenever warm food or drink contacts it and whenever a person chews on something like gum. Many cosmetic dentists now have metal-free practices , meaning that they offer no amalgam fillings, and even offer to replace those you have with more pleasing and healthy white fillings.

Acute mercury poisoning has recognized symptoms such as vomiting, difficulty with breathing, tremors, blindness and seizures. This is not what amalgam fillings would induce. There is also chronic mercury poisoning which creeps up on a person slowly over the years and decades. This is what worries many people, that illnesses we name differently, such as Chronic Fatigue Syndrome might really be chronic mercury poisoning.

Advantages of porcelain or composite fillings

Some dentists still offer amalgam fillings. It does take extra training to do porcelain and white fillings well. Increasing numbers of others offer metal-free fillings only. Aside from the mercury controversy, metal-free fillings provide several advantages over amalgam, namely:

· They do not expand in heat like the metal in amalgam and thus do not weaken teeth.
· They are more aesthetically appealing.
· They are bonded to the tooth, which holds it together and prolongs its life. In contrast, amalgam fillings are simply packed tightly into the cavity, putting outward pressure on the tooth perimeter
· Less healthy tooth tissue needs to be removed because the cavity does not have to be shaped to hold in the un-bonded amalgam.

To use amalgam or metal-free fillings is a decision made by you and your dentist. While research continues and final results are yet to be known, it rests on the individual to decide whether to live with possible risks from amalgam or to avoid them by opting for metal-free fillings.