EVERY dentist and nearly every adult alive have an ongoing and familiar relationship with dental amalgam, popularly known as “silver filling.” It contains mercury, silver, tin, copper and zinc. The high prevalence of tooth decay during much of the 20th century made it necessary to have a safe, efficient, durable and inexpensive dental restorative material available.

Health professionals and the public alike have widely viewed dental amalgam as satisfying these criteria. This had been the case for about a century. However, in recent times, claims of possible adverse health effects of mercury vapour from dental amalgam have surfaced with international publicity. In fact, for nearly five years, I have stopped using amalgam fillings in my clinic. In Sweden, the government banned its use altogether.

Research has detected elevated levels of elemental mercury vapour in the mouths of individuals with dental amalgam fillings. Additional animal research suggested that mercury from those dental fillings could be deposited in tissues distant from the site of amalgam placement. In some cases, the media sensationalised these findings, creating a spectre that dental amalgam may be detrimental to human health.

Considering the recent research reports, the international dental community asked the US Public Health Service to initiate a comprehensive scientific review of the benefits and risks of dental amalgam. After a two-year review, a diverse group of scientists comprising epidemiologists, toxicologists and biomaterial experts produced a report which was published in January 1993. Nearly 500 scientific studies were used as a basis for the report.

It was confirmed that dental amalgam can release very small amounts of elemental mercury. But mercury is absorbed from many sources, including food and even the air we breathe. It has not been demonstrated that most people experience any clinical effects from the small additional burden of mercury from amalgam. The report stated that if there were adverse health effects from mercury in silver amalgam fillings, they may be so subtle and non-specific that they would be difficult to detect.

The studies revealed that using that type of filling offers many advantages over the rest. These include wide potential of applications, ease of manipulation, reasonable clinical serviceability, and relatively low cost. Several alternative materials can replace dental amalgam in many traditional situations, particularly in low-stress-bearing areas. On a one-time-use basis, none of these materials is cheaper than dental amalgam.

Although the issue of potential health risks from dental amalgam initially drove the scientific review forward, the benefits of this material and the dangers of alternative restorative materials also assumed a prominent position. It is not enough to answer whether mercury from dental amalgam causes any bad health effects. The broader question should be asked, “How important is amalgam to the oral health of the nation?”. Indeed, millions of teeth have been retained among the Guyanese population over the years that otherwise would have been sacrificed because restorative alternatives would have been too expensive for many people.

In the final analysis, where there is a large known benefit, then individuals and society must acknowledge and determine an acceptable level of risk as the necessary side effect of a highly technological civilisation.