Dental Amalgam and Mercury Vapor Release

Abstract

Dental diseases are among the most common ailments, and dentists in the United States spend over 50% of their time in dental practice rebuilding carious, malformed, and traumatically injured teeth. It is logical, therefore, that the majority of the dental school curriculum is devoted to the diagnosis, prevention, and treatment of teeth with anomalies. Dentists have several choices of materials they can use to accomplish the task of rebuilding teeth. Besides amalgam, they have ceramic materials, resin composites, base-metal and noble casting alloys, and glass-ionomer cements to use to restore the posterior dentition. Each of these restorative materials has advantages and disadvantages, and the clinical judgment as to when a particular material should be used is given a high priority in dental education. Amalgam is the most widely used of these restorative materials, with 92% of dentists listing it as the material of choice in the posterior of the mouth (Clinical Research Associates, 1990). Dentists have been placing amalgams for over 150 years in the US. They placed 150 million last year, which represents over 75 tons of amalgam alloy. The reasons that dentists use this restorative material so frequently are its durability, ease of manipulation, and low cost. Numerous clinical studies have been conducted on the serviceability of amalgam. Most of these have been on the old, low-copper alloys, and results indicate that they last from 8 to 15 years (Bailit et al,, 1979; Osborne et al., 1980; Qvist et al., 1986). In the past 20 years, vast improvements have been made in amalgams with the development of the high-copper systems. Clinical studies initiated in the 1970's are reporting that the well-placed high-copper amalgam will last over 30 years (Laswell et al., 1989; Letzel et al., 1989; Osborne and Norman, 1990; Osborne et al., 1991). The ease with which amalgam is manipulated has no equal. Placement of amalgam takes only 20-50% of the time it takes to restore a tooth with other materials. For the amalgam, this cost in placement time and the cost to purchase the material are considerably less. The one factor that amalgam does not have in its favor is esthetics. The other-restorative materials, frankly, look better.