The Potential Adverse Health Effects of Dental Amalgam

Abstract

There is significant public concern about the potential health effects of exposure to mercury vapour (Hg(0)) released from dental amalgam restorations. The purpose of this article is to provide information about the toxicokinetics of Hg(0), evaluate the findings from the recent scientific and medical literature, and identify research gaps that when filled may definitively support or refute the hypothesis that dental amalgam causes adverse health effects. Dental amalgam is a widely used restorative dental material that was introduced over 150 years ago. Most standard dental amalgam formulations contain approximately 50% elemental mercury. Experimental evidence consistently demonstrates that Hg(0) is released from dental amalgam restorations and is absorbed by the human body. Numerous studies report positive correlations between the number of dental amalgam restorations or surfaces and urine mercury concentrations in non-occupationally exposed individuals. Although of public concern, it is currently unclear what adverse health effects are caused by the levels of Hg(0) released from this restoration material. Historically, studies of occupationally exposed individuals have provided consistent information about the relationship between exposure to Hg(0) and adverse effects reflecting both nervous system and renal dysfunction. Workers are usually exposed to substantially higher Hg(0) levels than individuals with dental amalgam restorations and are typically exposed 8 hours per day for 20-30 years, whereas persons with dental amalgam restorations are exposed 24 hours per day over some portion of a lifetime. This review has uncovered no convincing evidence pointing to any adverse health effects that are attributable to dental amalgam restorations besides hypersensitivity in some individuals.

The Release of Mercury from Amalgam Restorations and Its Health Effects: A Review

“…34 The authors noted that many studies report positive correlations between the number of amalgam restorations (or surfaces) and urine mercury concentrations in non-occupationallyexposed individuals. The authors also reported, however, that these correlations do not prove that increased urine mercury concentrations cause adverse health effects.…”

Changed Clinical Chemistry Pattern in Blood After Removal of Dental Amalgam and other Metal Alloys Supported by Antioxidant Therapy

“…A recent review uncovered no convincing evidence pointing to any adverse health effects that are attributable to dental amalgam restorations besides hypersensitivity in some individuals [16]. However, a study on 18 cadavers showed significantly higher total mercury levels in subjects with a greater number of occlusal amalgam surfaces compared with those with fewer occlusal amalgams in all types of tissues [17].…”

Casting the runes

“…The question remains, however, whether metallic mercury exposure from dental amalgams is the cause of adverse health effects, including multiple sclerosis, autism, CNS and renal damage, chronic fatigue, memory impairment and depression. These conditions and their etiology have been studied extensively and risk factors are well defined (see the review article by Brownawell et al 2005).…”