Composite (Plastic) Fillings & Sealants

It is believed that composite (plastic) fillings are much safer than mercury amalgam fillings over the long run. In some cases, though, there are important allergic sensitivity issues that need to be considered. It has also been shown in recent research that composite fillings, when properly placed by an experienced dentist, last nearly as long as mercury amalgam fillings (on average). Large composite fillings can be successfully placed by experienced dentists. One of the benefits is that unlike mercury amalgam fillings, little on no tooth material has to be drilled away to place the composite filling.

The allergic sensitivity issue can be an important one for some people. These people can use the
Clifford Materials Reactivity Testing procedure to reduce the likelihood of an allergic reaction to the dental materials. You can arrange this test yourself or your dentist can arrange for the test for you. My dentist told me that Conquest brand materials tend to cause fewer reactions than others he has tried.

The chronic toxicity issue is a complicated one. The composite fillings release estrogenic chemicals into the body. Significant exposure to estrogenic chemicals can cause health problems over time. However, after the first few days, the amount of release into the body is extremely small.

There is something in biological response to some chemicals known as the "U-shaped curve". As an example, when an exposure is at 100 units, it causes a specific health effect. At an exposure of 1 unit, it causes no observable effect. But at an exposure of 0.1 units, the chemical again causes a health effect. This can happen when, for example, the 0.1 dose causes a health effect, the 1.0 dose is high enough to cause different enzymes to protect the body and prevent effects, and the 100.0 dose overwhelms the body's defenses. This U-shaped curve seems to be what in seen in scientific research related to the compounds released from composite fillings and sealants. However, the dose released from these substances may even be below the lowest dose ever seen to cause effects (except for the time immediately after filling replacement).

The results of the these experiments was discussed in the March 24, 1997 issue of Chemical & Engineering News:

In the same Chemical & Engineering News article there is a discussion of the findings of a researcher researcher who found estrogenic compounds in patients' saliva soon after placement of composite materials:

The only contraindications I would suggest for placing composite fillings are during pregnancy and in cases of allergic reactions to the composite materials. It is possible that one day, new, non-metal materials may be found that are even safer than composite materials.