Sometime in the not-too-distant world of dentistry, mercury fillings will seem as old fashioned as drilling without Novocain or hygenists without latex gloves. Until then, patients can do what they’ve always done — listen to the options presented by their dentists and know that these fillings have been used successfully for more than a century.

A bill expected to be heard today in the Legislature would mandate what many dentists may do already — tell patients about their choices of filling material. Unfortunately, the bill goes beyond this, requiring dentists to tell patients about environmental issues related to the use of mercury and then requiring them to certify in writing that this information has been given.

Dentists currently have two choices for fillings — the mercury amalgam, which also contains silver, copper, zinc and tin, or a quartz composite. The composite is a little more expensive, more difficult for the dentist to use and, generally, does not last as long. However, one of its prime advantages is immediately apparent — it is tooth-colored or close to it. Because of appearance considerations and variations in stress on teeth from chewing, composites are regularly used on front teeth and metallic fillings on the back teeth.

But the color of the composite not only allows it to blend in better with teeth, it also signals that it does not contain mercury, which at high levels is toxic to the nervous system, and has been linked to multiple sclerosis, arthritis and mental disorders. The American Dental Association, the Food and Drug Administration and the U.S. Public Health Service say metallic fillings are safe, and certainly, after more than 100 years of use, there is no broad evidence that fillings are the direct cause of specific illnesses. Dentists, for instance, have been found to have a higher mercury load than the average American, but do not have a higher incidence of disease.

Nevertheless, mercury is a toxicant, so the less exposure to this element, the better. The question is whether the informed consent bill achieves that end in proportion to the problem. To do that, supporters of the bill must show that dentists in Maine fail to inform patients about the composite alternative. That is, before adding regulations, they should show that an information problem exists.

The Maine Dental Association already urges its members to discuss alternatives. A quick survey of dentists statewide could answer whether they do. The results of such a survey would decide whether the issue is worth pursuing.