It’s true that elemental mercury is very poorly absorbed through the gastrointestinal tract (1: World Health Organization; International Program on Chemical Safety. Inorganic mercury: environmental health criteria 118. Geneva: World Health Organization; 1991, www.inchem.org/documents/ehc/ehc/ehc118.htm) and this is sometimes used as an argument that it’s safe in dental amalgam “silver” fillings.
However, it’s also proven and well known that vapors released from elemental mercury are readily absorbed in the lungs, and is quickly diffused into the blood and distributed into all of the organs of the body, which bioaccumulates and has a very long half-life and is very neurotoxic (2: Research Triangle Institute; Agency for Toxic Substances and Disease Registry. Toxicological profile for mercury. Atlanta: US Department of Health and Human Services; 1999, www.atsdr.cdc.gov/toxprofiles/TP.asp?id=115&tid=24 (PDF www.atsdr.cdc.gov/toxprofiles/tp46.pdf).
Peer-reviewed scientific studies on monkeys have proven that dental amalgam “silver” fillings spread mercury throughout their tissues, (3: The FASEB Journal; Hahn LJ, Kloiber R, Leininger RW, Vimy MJ, Lorscheider FL.; Whole-body imaging of the distribution of mercury released from dental fillings into monkey tissues; www.ncbi.nlm.nih.gov/pubmed/2227216) also studies on sheep and women concluded that mercury originating from dental amalgam “silver” fillings transfered across the placenta onto the fetus, and into their milk. (4: Biological Trace Element Research; Vimy MJ, Hooper DE, King WW, Lorscheider FL.; Mercury from maternal “silver” tooth fillings in sheep and human breast milk. A source of neonatal exposure; www.ncbi.nlm.nih.gov/pubmed/9164660)
It has also been scientifically proven that dental amalgam “silver” fillings react with electromagentic radiation, such as from Wi-Fi devices, which increases vapor release (5: Journal of environmental health science & engineering; Maryam Paknahad, S. M. J. Mortazavi,corresponding author Shoaleh Shahidi, Ghazal Mortazavi, and Masoud Haghani; Effect of radiofrequency radiation from Wi-Fi devices on mercury release from amalgam restorations; www.ncbi.nlm.nih.gov/pmc/articles/PMC4944481/) and that tasks such as chewing gum or drinking hot liquids also increase mercury vapor release (6: Scandinavian Journal of Dental Research; Björkman L1, Lind B.; Factors influencing mercury evaporation rate from dental amalgam fillings.; www.ncbi.nlm.nih.gov/pubmed/1465570). (There is also an added major concern for me, as the increasing number of electromagnetic radiation from cellular phones and and other technologies are adding to this).
The sheer fact that mercury vapor is released whatsoever should be something of concern, however the ADA and FDA has been ignorant on this fact for a very long time and even tries to downplay it. There’s so much evidence against the use of dental amalgam “silver” fillings, and a multitude of countries have banned it altogether.
Thinking dental amalgam “silver” fillings is “safe because it has been used for 100 years” is a complete fallacy, you could say the same about e.g. asbestos or cigarettes.