Health complaints before and at one and five years after removal of dental amalgam restorations – data from a prospective cohort study in Norway
DOI:
https://doi.org/10.2340/aos.v83.40260Keywords:
Dental amalgam, prospective cohort study, subjective health complaints, medically unexplained symptomsAbstract
Objective: Health complaints attributed to dental amalgam fillings comprise both intraoral and general health complaints. There are data suggesting that patients with medically unexplained physical symptoms (MUPS) attributed to amalgam fillings show improvement in symptoms after removal of all amalgam fillings. However, data indicating changes of specific health complaints are limited. This study evaluated the changes of health complaints after removal of amalgam restorations in patients with health complaints attributed to dental amalgam fillings.
Method: Patients with MUPS attributed to dental amalgam (Amalgam cohort) had all their amalgam fillings removed. The participants indicated an intensity of 11 local and 12 general health complaints on numeric rating scales before the treatment and at follow-up after 1 and 5 years. The comparison groups comprising a group of healthy individuals and a group of patients with MUPS without symptom attribution to dental amalgam did not have their amalgam restorations removed.
Results: In the Amalgam cohort, mean symptom intensity was lower for all 23 health complaints at follow-up at 1 year compared to baseline. Statistically significant changes were observed for specific health complaints with effect sizes between 0.36 and 0.68. At the 5-year follow-up, the intensity of symptoms remained consistently lower compared to before the amalgam removal. In the comparison groups, no significant changes of intensity of symptoms of health complaints were observed.
Conclusion: After removal of all amalgam restorations, both local and general health complaints were reduced. Since blinding of the treatment was not possible, specific and non-specific treatment effects cannot be separated.
Downloads
References
Shen C. Dental amalgams. In: Anusavice KJ, Shen C, Rawls HR, editors. Phillips’ science of dental materials. 12th ed. St. Lou-is, MO: Elsevier/Saunders; 2013. p. 340–63.
SCENIHR (Scientific Committee on Emerging and Newly-Identified Health Risks). Opinion on the safety of dental amalgam and alternative dental restoration materials for patients and users (update), 29 April, 2015. Luxembourg: European Commis-sion, DG Health and Food Safety; 2015.
Bates MN. Mercury amalgam dental fillings: an epidemiologic assessment. Int J Hyg Environ Health. 2006 Jul;209(4):309–16. https://doi.org/10.1016/j.ijheh.2005.11.006 DOI: https://doi.org/10.1016/j.ijheh.2005.11.006
Sandborgh-Englund G, Elinder CG, Johanson G, et al. The absorption, blood levels, and excretion of mercury after a single dose of mercury vapor in humans. Toxicol Appl Pharmacol. 1998;150(1):146–53. https://doi.org/10.1006/taap.1998.8400 DOI: https://doi.org/10.1006/taap.1998.8400
Risher JF, World Health Organization & International Programme on Chemical Safety. Elemental mercury and inorganic mer-cury compounds: human health aspects. World Health Organization; 2003. [cited 2024 March 12] Available from: https://apps.who.int/iris/handle/10665/42607
Berlin M, Zalups RK, Fowler BA. Mercury. In: Nordberg GF, Fowler BA, Nordberg M, editors. Handbook on the toxicology of metals. Amsterdam, Netherlands: Elsevier; 2014. p. 1013–75. DOI: https://doi.org/10.1016/B978-0-444-59453-2.00046-9
Svare CW, Peterson LC, Reinhardt JW, et al. The effect of dental amalgams on mercury levels in expired air. J Dent Res. 1981;60(9):1668–71. https://doi.org/10.1177/00220345810600090601 DOI: https://doi.org/10.1177/00220345810600090601
Björkman L, Lind B. Factors influencing mercury evaporation rate from dental amalgam fillings. Scand J Dent Res. 1992;100(6):354–60. https://doi.org/10.1111/j.1600-0722.1992.tb01086.x DOI: https://doi.org/10.1111/j.1600-0722.1992.tb01086.x
Clarkson TW, Magos L. The toxicology of mercury and its chemical compounds. Crit Rev Toxicol. 2006 Sep;36(8):609–62. https://doi.org/10.1080/10408440600845619 DOI: https://doi.org/10.1080/10408440600845619
World Health Organization. 10 chemicals of public health concern. World Health Organization; 2020 [cited 2023 Apr 27]. Avail-able from: https://www.who.int/news-room/photo-story/photo-story-detail/10-chemicals-of-public-health-concern
Brownawell AM, Berent S, Brent RL, et al. The potential adverse health effects of dental amalgam. Toxicol Rev. 2005;24(1):1–10. https://doi.org/10.2165/00139709-200524010-00001 DOI: https://doi.org/10.2165/00139709-200524010-00001
Sjursen TT, Binder P-E, Lygre GB, et al. How unexplained health complaints were attributed to dental amalgam. Nor-dic Psychol. 2014;66(3):216–29. https://doi.org/10.1080/19012276.2014.964958 DOI: https://doi.org/10.1080/19012276.2014.964958
McCullough MJ, Tyas MJ. Local adverse effects of amalgam restorations. Int Dent J. 2008 Feb;58(1):3–9. https://doi.org/10.1111/j.1875-595X.2008.tb00170.x DOI: https://doi.org/10.1111/j.1875-595X.2008.tb00170.x
Issa Y, Duxbury AJ, Macfarlane TV, et al. Oral lichenoid lesions related to dental restorative materials. Br Dent J. 2005 Mar 26;198(6):361–6; disussion 549; quiz 372. https://doi.org/10.1038/sj.bdj.4812176 DOI: https://doi.org/10.1038/sj.bdj.4812176
Weidenhammer W, Bornschein S, Zilker T, et al. Predictors of treatment outcomes after removal of amalgam fillings: associa-tions between subjective symptoms, psychometric variables and mercury levels. Community Dent Oral Epidemiol. 2010 Apr;38(2):180–9. https://doi.org/10.1111/j.1600-0528.2009.00523.x DOI: https://doi.org/10.1111/j.1600-0528.2009.00523.x
Berlin M. Mercury in dental amalgam: a risk analysis. Neurotoxicology. 2020 Dec;81:382–6. https://doi.org/10.1016/j.neuro.2020.09.034 DOI: https://doi.org/10.1016/j.neuro.2020.09.034
Richardson GM. Assessment of mercury exposure and risks from dental amalgam. Final report. Medical Devices Bureau, En-vironmental Health Directorate. Health Canada, Ottawa; 1995.
Andreoli V, Sprovieri F. Genetic aspects of susceptibility to mercury toxicity: an overview. Int J Environ Res Public Health. 2017 Jan 18; 14(1):93. https://doi.org/10.3390/ijerph14010093 DOI: https://doi.org/10.3390/ijerph14010093
Rathore M, Singh A, Pant VA. The dental amalgam toxicity fear: a myth or actuality. Toxicol Int. 2012 May;19(2):81–8. https://doi.org/10.4103/0971-6580.97191 DOI: https://doi.org/10.4103/0971-6580.97191
Rasines Alcaraz MG, Veitz-Keenan A, Sahrmann P, et al. Direct composite resin fillings versus amalgam fillings for permanent or adult posterior teeth. Cochrane Database Syst Rev. 2014 Mar 31(3):Cd005620. https://doi.org/10.1002/14651858.CD005620.pub2 DOI: https://doi.org/10.1002/14651858.CD005620.pub2
Spencer AJ. Dental amalgam and mercury in dentistry. Aust Dent J. 2000 Dec;45(4):224–34. https://doi.org/10.1111/j.1834-7819.2000.tb00256.x DOI: https://doi.org/10.1111/j.1834-7819.2000.tb00256.x
Jackson JL, George S, Hinchey S. Medically unexplained physical symptoms. J Gen Intern Med. 2009 Apr;24(4):540–2. https://doi.org/10.1007/s11606-009-0932-x DOI: https://doi.org/10.1007/s11606-009-0932-x
Norwegian Ministry of Health and Care Services. Tilgjengelighet, kompetanse og sosial utjevning. Framtidas tannhelsetjenes-ter. Oslo: Helse-og omsorgsdepartementet; 2006.
Björkman L, Musial F, Alraek T, et al. Removal of dental amalgam restorations in patients with health complaints attributed to amalgam: a prospective cohort study. J Oral Rehabil. 2020 Nov;47(11):1422–34. https://doi.org/10.1111/joor.13080 DOI: https://doi.org/10.1111/joor.13080
Lamu AN, Robberstad B, Hamre HJ, et al. Validity and responsiveness of GHC-index in patients with amalgam-attributed health complaints. Acta Odontol Scand. 2021 Oct 15:1–8.
Melchart D, Wuhr E, Weidenhammer W, et al. A multicenter survey of amalgam fillings and subjective complaints in non-selected patients in the dental practice. Eur J Oral Sci. 1998 Jun;106(3):770–7. https://doi.org/10.1046/j.0909-8836.1998.eos106303.x DOI: https://doi.org/10.1046/j.0909-8836.1998.eos106303.x
Sawilowsky SS. New effect size rules of thumb. J Modern Applied Statistical Methods. 2009;8(2 Article 26):597–9. https://doi.org/10.22237/jmasm/1257035100 DOI: https://doi.org/10.22237/jmasm/1257035100
Rothman KJ. No adjustments are needed for multiple comparisons. Epidemiology. 1990 Jan;1(1):43–6. https://doi.org/10.1097/00001648-199001000-00010 DOI: https://doi.org/10.1097/00001648-199001000-00010
Sullivan GM, Feinn R. Using effect size-or why the P value is not enough. J Grad Med Educ. 2012 Sep;4(3):279–82. https://doi.org/10.4300/JGME-D-12-00156.1 DOI: https://doi.org/10.4300/JGME-D-12-00156.1
Lygre GB, Sjursen TT, Svahn J, et al. Characterization of health complaints before and after removal of amalgam fillings – 3-year follow-up. Acta Odontol Scand. 2013 May-Jul;71(3–4):560–9. https://doi.org/10.3109/00016357.2012.697577 DOI: https://doi.org/10.3109/00016357.2012.697577
Melchart D, Vogt S, Kohler W, et al. Treatment of health complaints attributed to amalgam. J Dent Res. 2008 Apr;87(4):349–53. https://doi.org/10.1177/154405910808700410 DOI: https://doi.org/10.1177/154405910808700410
Nerdrum P, Malt UF, Hoglend P, et al. A 7-year prospective quasi-experimental study of the effects of removing dental amalgam in 76 self-referred patients compared with 146 controls. J Psychosom Res. 2004 Jul;57(1):103–11. https://doi.org/10.1016/S0022-3999(03)00542-7 DOI: https://doi.org/10.1016/S0022-3999(03)00542-7
Zwicker JD, Dutton DJ, Emery JC. Longitudinal analysis of the association between removal of dental amalgam, urine mercury and 14 self-reported health symptoms. Environ Health. 2014;13:95. https://doi.org/10.1186/1476-069X-13-95 DOI: https://doi.org/10.1186/1476-069X-13-95
Lindh U, Hudecek R, Danersund A, et al. Removal of dental amalgam and other metal alloys supported by antioxidant therapy alleviates symptoms and improves quality of life in patients with amalgam-associated ill health. Neuro Endocrinol Lett. 2002 Oct-Dec;23(5–6):459–82.
Björkman L, Musial F, Alræk T, et al. Mercury, silver and selenium in serum before and after removal of amalgam resto-rations: results from a prospective cohort study in Norway. Acta Odontol Scand. 2023 Nov 16;81(4):298–310. https://doi.org/10.1080/00016357.2022.2143422 DOI: https://doi.org/10.1080/00016357.2022.2143422
Food and Drug Administration. Information for patients about dental amalgam fillings. US Food and Drug Administration; 2020 [updated 2020 Sep 24; cited 2023 Apr 25]. Available from: https://www.fda.gov/medical-devices/dental-amalgam-fillings/information-patients-about-dental-amalgam-fillings
Kishi R, Doi R, Fukuchi Y, et al. Subjective symptoms and neurobehavioral performances of ex-mercury miners at an average of 18 years after the cessation of chronic exposure to mercury vapor. Mercury Workers Study Group. Environ Res. 1993 Aug;62(2):289–302. https://doi.org/10.1006/enrs.1993.1114 DOI: https://doi.org/10.1006/enrs.1993.1114
Mathiesen T, Ellingsen DG, Kjuus H. Neuropsychological effects associated with exposure to mercury vapor among former chloralkali workers. Scand J Work Environ Health. 1999 Aug;25(4):342–50. https://doi.org/10.5271/sjweh.444 DOI: https://doi.org/10.5271/sjweh.444
Hill AB. The environment and disease: association or causation? Proc R Soc Med. 1965 May;58:295–300. https://doi.org/10.1177/003591576505800503 DOI: https://doi.org/10.1177/003591576505800503
Rothman KJ, Greenland S. Hill’s criteria for causality. 2014. In: Wiley StatsRef: Statistics Reference Online [Internet]. [cited 2024 March 12] Available from: https://onlinelibrary.wiley.com/doi/abs/10.1002/9781118445112.stat05168.
Sjursen TT, Lygre GB, Dalen K, et al. Changes in health complaints after removal of amalgam fillings. J Oral Rehabil. 2011 Nov;38(11):835–48. https://doi.org/10.1111/j.1365-2842.2011.02223.x DOI: https://doi.org/10.1111/j.1365-2842.2011.02223.x
Stenman S, Grans L. Symptoms and differential diagnosis of patients fearing mercury toxicity from amalgam fillings. Scand J Work Environ Health. 1997;23 Suppl 3:59–63.
Björkman L, Sjursen TT, Dalen K, et al. Long term changes in health complaints after removal of amalgam restorations. Acta Odontol Scand. 2017 Apr;75(3):208–19. https://doi.org/10.1080/00016357.2016.1278262 DOI: https://doi.org/10.1080/00016357.2016.1278262
Björkman L, Lundekvam BF, Laegreid T, et al. Mercury in human brain, blood, muscle and toenails in relation to exposure: an autopsy study. Environ Health. 2007;6:30. https://doi.org/10.1186/1476-069X-6-30 DOI: https://doi.org/10.1186/1476-069X-6-30
Additional Files
Published
Issue
Section
License
Copyright (c) 2024 Nivedita Sinha, Harald Johan Hamre, Frauke Musial, Erik L. Werner, Lars Björkman
This work is licensed under a Creative Commons Attribution 4.0 International License.
Acta Odontologica Scandinavica publishes original research papers as well as critical reviews relevant to the diagnosis, epidemiology, health service, prevention, aetiology, pathogenesis, pathology, physiology, microbiology, development and treatment of diseases affecting tissues of the oral cavity and associated structures including papers on cause and effect or explanatory/associative relationships for experimental or observational studies.
