Nicholson John W.
Bluefield Centre for Biomaterials, London, United Kingdom + Queen Mary University of London, Barts & The London School of Medicine and Dentistry, Institute of Dentistry, Dental Physical Sciences, London, United Kingdom
Abstract
This paper sets out the current position with respect to the replacement of dental amalgam as a restorative material. The environmental impact and the question of possible adverse effects of mercury on human health, including that of dental personnel, are reviewed. The literature has been surveyed using Pub Med with the following key words employed: dental amalgam; environmental; disposal; alternative materials. This identified a large number of papers, and more recent ones were selected for inclusion, particularly where they summarised the earlier literature. The findings of this process are that dental amalgam remains a popular and widely used material which, with appropriate hygiene measures, does not pose a threat to human health. However, environmental concerns with the mining, transport and technical uses of mercury led to the Minamata Convention in 2013, one consequence of which is that mining of mercury will cease from the year 2032. This means that dental amalgam will no longer be available for use. This article considers alternative materials. Results from the literature show that neither of the main possibilities, namely composite resins of glass-ionomer cements, compares with amalgam in terms of strength or durability. The impact of this on the dental profession is discussed briefly.
Keywords: Dental Amalgam; Replacement; Environmental; Disposal; Alternative Materials
Reference
*** IADR website. https://www.iadr.org/science-policy/safetydental-amalgam. Accessed 17 th February 2023
*** Minamata Convention website. http://www. mercuryconvention.org/en. Accessed 16th February 2023
Aaseth, J., Hilt, B., Borklund, G. (2018) Mercury exposure and health impacts in dental personnel. Environ Res, 164:65-69
Acciari, H.A., Guastaldi, A.C., Brett, C.M.A. (2001) Corrosion of dental amalgams: electrochemical study of Ag-Hg, Ag-Sn and Sn-Hg phases. Electrochim Acta, 46:3887-3893
Agnihotry, A., Federowicz, Z., Nasser, M. (2016) Adhesively bonded versus non-bonded amalgam restorations for dental caries. Cochrane Libr, 3: CD007517
Antony, K., Gesner, D., Hiebinger, C., Windisch, F. (2008) Longevity of dental amalgam in comparison to composite materials. GMS Health Technol Assess, 4:Document 12
Anusavice, K., Shen, C., Rawls, H.R., eds. (2012) Phillips’ Science of Dental Materials. Philadelphia: W.B. Saunders Inc, 12th ed
Baek, H.J., Kim, E.K., Lee, S.G., Jeong, S.H., Sakong, J., Merchant, A.T., Im, S.U., Song, K.B., Choi, Y.H. (2016) Dental amalgam exposure can elevate urinary mercury concentrations in children. Int Dent J, 66:136-143
Bakhurji, E., Scott, T., Mangione, T., Sohn, W. (2017) Dentists’ perspective about dental amalgam: current use and future direction. J Public Health Dent, 77:181-182
Bates, M.N., Fawcett, J., Garrett, N., Curess, T., Kjellstrom, T. (2004) Health effects of dental amalgam exposure: a retrospective cohort study. Int J Epid, 33:894-902
Bedir, F.R., Celik, H.T., Ersoy, A.O., Tasci, Y., Moraloglu, O., Karakaya, J. (2016) Mercury concentration in maternal serum, cord blood, and placenta in patients with amalgam dental fillings: effects on fetal biometric measurements. J Matern Fetal Neonatal Med, 29:3665-3669
Bellinger, D.C., Trachtenberg, F., Barregard, L., Tavares, M., Cernichiari, E., Daniel, D., Mckinlay, S. (2006) Neuropsychological and renal effects of dental amalgam in children: A randomized clinical trial. JAMA, 295:1775-1783
Bengtsson, U.G., Hylander, L.D. (2017) Increased mercury emissions from modern dental amalgams. Biometals, 30:277-283
Berlin, M., Zalups, R.K., Fowler, B.A. (2007) Mercury. u: Nordberg G., Fowler B.A., Nordberg M., Friberg T. [ur.] Handbook on the toxicology of metals, Burlington: Academic Press, 3 rd ed
Bittner, J.A.C., Echeverria, D., Woods, J.S., Aposhian, H.V., Naleway, C., Martin, M.D., Mahurin, R.K., Heyer, N.J., Iaciola, M. (1998) Behavioural effects of low-level exposure to Hg0 among dental professionals: a cross-study evaluation of psychomotor effects. Neurotoxicol Teratol, 20:429-439
Bjorklund, G., Dadar, M., Aaseth, J. (2018) Delayed-type hypersensitivity to metals in connective tissue disease and fibromyalgia. Environ Res, 161:573-579
Burgess, J.O., Walker, R., Davidson, J.M. (2002) Posterior resinbased composite: review of the literature. Pediatr Dent, 24:465-479
Chadwick, R.G., Lloyd, C.H. (2022) Dental amalgam: the history and legacy you perhaps never knew?. Br Dent J, 232:633-637
1
Chin, G., Chong, J., Kluczewska, A., Lau, A., Gorjy, S., Tennant, M. (2000) The environmental effects of dental amalgam. Aust Dent J, 45:246-249
Christenson, G. (2010) Should resin-based composite dominate restorative dentistry today?. J Am Dent Assoc, 141:1490-1493
de Amorim, R.G., Leal, S.C., Frencken, J.E. (2012) Survival of atraumatic restorative treatment (ART) sealants and restorations: a meta-analysis. Clin Oral Investi, 16:429-441
Derouen, T.A., Martin, M.D., Leroux, B.G., Townes, B.D., Woods, J.S., Leitão, J., Castro-Caldas, A., Luis, H., Bernardo, M., Rosenbaum, G., Martens, I.P. (2006) Neurobehavioral effects of dental amalgam in children: A randomized clinical trial. JAMA, 295:1784-1792
Drummond, J.L., Liu, Y., Wu, T.Y., Cailas, M.D. (2003) Particle versus mercury removal efficiency of amalgam separators. J Dent, 31:51-58
Ekino, S., Susa, M., Ninomiya, T., Imamura, K., Kitamura, T. (2007) Minamata disease revisited: An update on the acute and chronic manifestations of methyl mercury poisoning. J Neurol Sci, 262:131-144
El, M.O., El, M.N. (2019) The global decline in the use of dental amalgam restorations. Mod Res Dent, 4:415-417
Ertas, E., Aksoy, A., Turla, A., Karaarsian, E.S., Karaarsian, B., Aydin, A., Eken, A. (2014) Human brain mercury levels related to exposure to amalgam fillings. Hum Exp Toxicol, 33:873-877
Estrich, C.G., Lipman, R.D., Aranjo, M.W.B. (2021) Dental amalgam restorations in nationally representative sample of the US population aged ≥ 15 years: NHANES 2011-2016. J Public Health Dent, 81:327-330
European Commission Scientific Committee on Emerging and Newly Identified Health Risks (2015) Opinion on the safety of dental amalgam and alternative dental restorative materials for patients and users. European Union, adopted 29th April
Fairbanks, S.D., Pramanik, S.K., Thomas, J.A., Das, A., Martin, N. (2021) The management of mercury from dental amalgam in wastewater effluent. Environ Technol Rev, 10:213-223
Fathi, M., Mortazavi, V. (2004) A review on dental amalgam corrosion and its consequences. J Res Med Sci, 1:42-51
Frencken, J., Liang, S., Zhang, Q. (2021) Survival estimates of atraumatic restorative treatment versus traditional restorative treatment: a systematic review with meta-analyses. Br Dent J
Gallusi, G., Libonati, A., Piro, M., di Taranto, V., Montemurro, E., Campanella, V. (2021) Is dental amalgam a higher risk factor than resin-based restorations for systemic conditions? A systematic review. Materials (Basel), 14: Article 1980
Golding, J., Steer, C.D., Gregory, S., Lowery, T., Hibbeln, J.R., Taylor, C.M. (2016) Dental associations with blood mercury in pregnant women. Community Dent Oral Epidemiol, 44:216-222
Haj-Ali, R., Mary, P.W., Karen, W. (2005) Survey of general dentists regarding posterior restorations, selection criteria and associated clinical problems. Gen Dent, 53:1369-1375
Hall, D., Meadows, M., Eckret, G. (2009) Dental amalgam use by Indiana dentists. J. Indiana Dent Assoc, 88:25-32
Harada, M. (1995) Minamata disease: Methyl mercury poisoning in Japan caused by environmental pollution. Crit Rev Toxicol, 25:1-24
Hilt, B., Svendson, K., Syversen, T., Aas, O., Qvenild, T., Sletvold, H., Mele, I. (2009) Occurrence of cognitive symptoms in dental assistants with previous occupational exposure to metallic mercury. Neurotoxicology, 30:1202-1206
Holland, R.J. (1993) Release of mercury vapor from dental amalgam. Dent Mater, 9:99-103
Homme, K.G., Kern, J.K., Haley, B.E., Geier, D.A., King, P.G., Sykes, L.K., Geier, M.R. (2014) New science challenges old notion that mercury dental amalgam is safe. Biometals, 27:19-24
Hong, Y.-.S., Kim, Y.-.M., Lee, K.-.E. (2012) Methyl mercury exposure and health effects. J Prev Med Public Health, 45:353-363
Honkala, S., Vereecken, C., Niclasen, B., Honkala, E. (2015) Trends in toothbrushing in 20 countries/regions from 1994 to 2010. Eur J Public Health, 25:20-23
Horsted-Bindslev, P. (2004) Amalgam toxicity – environmental and occupational hazards. J Dent, 32:359-364
International Organization for Standardization (2008) Dental equipment – Amalgam separators. Geneva: ISO, ISO Standard 11143
International Programme on Chemical Safety (2003) Elemental mercury and inorganic mercury compounds: human health aspects. World Health Organization, UN Environment Programme
Jirau-Colon, H., González-Parrilla, L., Martinez-Jiménez, J., Adam, W., Jiménez-Velez, B. (2019) Rethinking the dental amalgam dilemma: An integrated toxicological approach. Int J Environ Res Pub Health, 16:Article 1036
Johnston (2019) Amalgam and the environment. Br Dent J, 226:640
Jokstad, A., Fan, P.L. (2006) Amalgam waste management. Int Dent J, 56:147-153
Letzel, H., de Boer, F.A., Van’t, H.M.A. (1997) An estimation of the size distribution of amalgam particles in dental treatment water. J Dent Res, 76:780-788
Lorscheider, F.L., Vimy, M.J., Summers, A.O. (1995) Mercury exposure from ‘silver’ tooth fillings: emerging evidence questions a traditional dental paradigm. FASEB J, 9:504-508
Lygre, G.B., Haug, K., Skjaerven, R., Björkman, L. (2016) Prenatal exposure to dental amalgam and pregnancy outcome. Community Dent Oral Epidemiol, 44:442-449
Mackert, J.R., Wahl, M.J. (2004) Are there acceptable alternatives to amalgam?. J Calif Dent Assoc, 32:601-610
Mahler, D.B. (1997) The high-copper dental amalgam alloy. J Dent Res, 76:537-541
Marek, M. (1997) Dissolution of mercury from dental amalgam at different pH values. J Dent Res, 76:1308-1315
Mills, A. (1990) Mercury and crematorium chimneys. Nature, 346:615
Mitchell, R.J., Okabe, T. (1996) Setting reactions in dental amalgam. Part 1. Phases and microstructure between one hour and one week. Crit Rev Oral Biol Med, 7:12-22
Mitchell, R.J., Koike, M., Okabe, T. (2007) Posterior amalgam restorations – usage, regulation and longevity. Dent Clin North Am, 51:573-589
Moberg, L., Johansson, C. (1991) Release of corrosion products from amalgam in phosphate containing solutions. Scand J Dent Res, 99:75-85
Mulligan, S., Kariuki, G., Gathace, L.W. (2018) The environmental impact of dental amalgam and resin-based composite materials. Br Dent J, 19:38-45
Mutter, J., Naumann, J., Sadaghian, C., Walach, H., Drasch, G. (2004) Amalgam studies: disregarding basic principles of mercury toxicity. Int J Hyg Environ Health, 207:391-397
Nagpal, N., Bettiol, S.S., Isham, A., Hoang, H., Crocombe, L.A. (2017) A review of mercury exposure and health of dental personnel. Safety Health Work, 8:1-10
Naimi-Akbar, A., Sandborgh-Englund, G., Ekbom, A., Ekstrand, J., Näsman, P., Montgomery, S. (2014) Mortality among sons of female dental personnel – a national cohort study. J Perinatal Med, 42:655-661
Nakamura, N., Yamada, A., Iwamoto, T., Arakai, M., Tanaka, K., Aizawa, S., Nonaka, K., Fukumoto (2009) Two-year clinical evaluation of flowable composite resin containing pre-reacted glass ionomer. Pediatr Dent J, 19:89-97
Neghab, M., Choubineth, A., Zadeh, J.H., Ghaderi, E. (2011) Symptoms of intoxication in dentists associated with exposure to low levels of mercury. Ind Health, 49:249-254
Nicholson, J.W. (2017) Emerging ethical issues in restorative dentistry. New Bioethics, 23:236-248
Nicholson, J.W. (2023) Opinion piece: Can we stop using dental amalgam?. Online J Dent Oral Health, 6:Article 000643
Nicholson, J.W. (2020) Metals. u: Nicholson JW. [ur.] The chemistry of medical and dental materials, Cambridge: Royal Society of Chemistry, 2nd ed, Ch 4
Okabe, T., Elvebak, B., Carrasco, L., Ferrecane, J.L., Keanini, R.G., Nakajima, H. (2003) Mercury release from dental amalgams into continuously replenished liquids. Dent Mater, 19:38-45
Osborne, J.W. (2006) Creep as a mechanism for sealing amalgams. Oper Dent, 31:161-164
Osiro, O.A., Kariuki, D.K., Gathace, L.W. (2019) The Minamata Convention on mercury and its implication for the management of dental caries in lowand middle-income countries. Int Dent J, 69:247-251
Pair, L., Udin, D., Tanbonliong, T. (2004) Materials used to restore class II lesions in primary molars: A survey of Californian pediatric dentists. Pediatr Dent, 26:501-507
Richardson, G.M., Wilson, R., Allard, D., Purtill, C., Douma, S., Graviere, J. (2011) Mercury exposure and risks from dental amalgam in the US population, post-2000. Sci Total Environ, 409:4257-4268
Ritchie, K.A., Gilmour, W.H., Macdonald, E.N., Burke, F.J., Mcgowen, D.A., Dale, I.M., Hammersley, R., Hamilton, R.M., Binnie, V., Collington, D. (2002) Health and neuropsychological functioning of dentists exposed to mercury. Occup Environ Med, 59:287-293
Setcos, J.C., Staninec, M., Wilson, N.H.F. (1999) The development of resin-bonding for amalgam restorations. Br Dent J, 186:328-332
Shapiro, I.M., Cornblath, D.R., Sumner, A.J., Uzzell, B., Spitz, L.K., Ship, I.I., Bloch, P. (1982) Neurophysiological and neuropsychological function in mercury-exposed dentists. Lancet, 1:1147-1150
Sletvold, H., Svendsen,, Aas, O., Syversen, T., Hilt, B. (2012) Neuropsychological function and past exposure to metallic mercury in female dental workers. Scand J Psychol, 53:136-143
Stejskal, V., Ockert, K., Bjorklund, G. (2013) Metal-induced inflammation triggers fibromyalgia in metal-allergic patients. Neuro Endocrine Lett, 34:559-565
Stejskal, V. (2014) Metals as a common trigger of inflammation resulting in non-specific symptoms: diagnosis and treatment. Ist Med Assoc J, 16;753-758
Sterzl, I., Prochazkova, J., Hrda, P., Bartova, J., Marucha, P. (1999) Stejskal Mercury and nickel allergy: risk factors in fatigue and autoimmunity. Neuro Endocrine Lett, 20:221-228
Thygesen, L.C., Flachs, E.M., Hanehoj,, KjuusH,, Juel, K. (2011) Hospital admissions for neurological and renal diseases among dentists and dental assistants occupationally exposed to mercury. Occup Environ Med, 68:895-901
Ucar, Y., Brantley, W.A. (2011) Biocompatibility of dental amalgams. Int J Dent, Article 981595
UK Department for the Environment and Rural Affairs (DEFRA) (2012) Process guidance note 5/2 (12): Statutory guidance for crematoria. September
UK Department of Health and Social Care (2019) National plan to phase down the use of dental amalgam in England. 27th June
US Agency for Toxic Substances and Disease Registry (ATSDR) (1999) Toxicological profile for mercury. Public Health Service – US Department of Health and Human Services
US Environmental Protection Agency, EPA (1995) Mercury, elemental: reference concentration for chronic inhalation exposure (RfC). u: Integrated risk information system, US EPA
Vähäsarja, N., Montgomery, S., Sandborgh-Englund, G., Ekbom, A., Ekstrand, J., Näsman, P., Naimi-Akbar, A. (2016) Neurological disease or intellectual disability among sons of female Swedish dental personnel. J Perinatal Med, 44:453-460
Velo, M.D.A.C., Scoiit, C.K., Bastos, N.A., Funise, A.Y., Mondelli, J. (2018) Amalgam restorations and future perspectives. J Odontol, 2: Article 1000102
Woods, J.S., Martin, M.D., Leroux, B.G., Derouen, T.A., Leitao, J.G., Beranardo, M.F., Luis, H.S., Simmonds, L., Kushleika, J.V., Huang, Y. (2007) The contribution of dental amalgam to urinary mercury excretion in children. Environ Health Perspect, 115:1527-1531
Worthingon, H.V., Khangura, S., Seal, K., Mierzwinskiurban, M., Veitz-Keenan, A., Sahrmann, P., Davies, D., et al. (2021) Direct composite resin fillings versus amalgam fillings for permanent posterior teeth. Cochrane Libr, 8:CD005620
1
Yap, A.U.J., Ng, B.L., Blackwood, D.J. (2004) Corrosion behaviour of high copper dental amalgams. J Oral Rehabil, 31:595-599
Balkan Journal of Dental Medicine, 2023, vol. 27, br. 2, str. 63-72