Escrito por: Samuel Zwetchkenbaum, DDS, MPH
Should I worry about mercury in dental fillings?
With last winter’s story of a Fall River man hospitalized from acute mercury poisoning related to melting dental scrap , should individuals with fillings be concerned? Is there a need to remove fillings? In short: no! But read this post to learn more about mercury, amalgam fillings, and more.
A brief review of mercury
Mercury occurs in nature in different forms. Organic mercury is mercury combined with carbon-containing compounds. A common form of organic mercury is methylmercury which is produced by microorganisms in water and soil, and is found in seafood. Elemental mercury is a silvery, odorless liquid that evaporates slowly at room temperature, becoming a vapor. When alloyed with metals, its availability as a vapor becomes negligible. Finally, inorganic mercury is mercury combined with other chemical elements such as chlorine, sulfur or oxygen. These forms are found in industry and remain stable (provided they are not melting it!).
Amalgam fillings have been a workhorse for dentistry for many years. They are long-lasting, effective, easy to place and can be smoothed and polished to allow excellent service. Mercury as an element is alloyed with metals, including silver, tin, and copper. Once the filling is solid, it no longer contains elemental mercury. While newer filling materials are available that have the advantage of better esthetics, many dentists continue to place amalgams due to the above-named advantages. Most dentists do not recommend removal if the filling is sound, free from decay, and not an esthetic concern.
What happened in a home in Fall River is very different from what is going on in most people’s mouths. The act of taking hundreds of old teeth and fillings and subjecting them to cooking temperatures is extremely dangerous and will lead to acute mercury poisoning. While there are metal-extracting companies that work with dentists to recycle metals, this is typically done in a very controlled setting and should never be done at home.
Human exposure to mercury can be assessed by looking at urinary concentrations. Studies looking at health differences between individuals with amalgam restorations have not found any health differences between individuals with and without amalgam restorations. Further, no studies have shown health benefits of removal of amalgam restorations. Numerous professional organizations also say that amalgam poses no health risk based on research.
Newer fillings materials and techniques
Dental filling materials continue to improve. Composite, or “white”, fillings are a combination of polymer resin and glass. These may take more time to place in order to have an excellent result. Glass ionomer filling materials provide microscopic fluoride release to prevent decay around the edges of the filling. Newer bioactive filling materials are emerging which encourage teeth to repair themselves.
Dentistry has changed significantly over the years. With newer instrumentation, more esthetic materials, radiographs requiring less radiation, and more, it is a great time to be a patient! What remains consistent is the goal of preventing dental disease. Be sure to keep up with daily plaque removal, a diet low in processed sugars, and effective use of cavity-fighting fluorides and you are taking an important step!
This post was written by:
Samuel Zwetchkenbaum, DDS, MPH
Dental Director, Oral Health Program
Center for Preventive Services
Division of Community Health & Equity
Rhode Island Department of Health