Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
Clinical Trial
. 2018 Dec 7;13(12):e0208803.
doi: 10.1371/journal.pone.0208803. eCollection 2018.

Perinatal death and exposure to dental amalgam fillings during pregnancy in the population-based MoBa cohort

Lars Björkman  1   2 , Gunvor B Lygre  1 , Kjell Haug  3 , Rolv Skjærven  3   4
Affiliations
Clinical Trial

Perinatal death and exposure to dental amalgam fillings during pregnancy in the population-based MoBa cohort

Lars Björkman et al. PLoS One. .

Abstract

Objectives: The aim was to gain knowledge regarding the risk of perinatal death related to exposure to dental amalgam fillings in the mother.

Design: Population-based observational cohort study.

Setting: The Norwegian Mother and Child Cohort Study, a Norwegian birth cohort of children born in 1999-2008 conducted by the Norwegian Institute of Public Health.

Participants: 72,038 pregnant women with data on the number of teeth filled with dental amalgam.

Main outcome measures: Data on perinatal death (stillbirth ≥ 22 weeks plus early neonatal death 0-7 days after birth) were obtained from the Medical Birth Registry of Norway.

Results: The absolute risk of perinatal death ranged from 0.20% in women with no amalgam-filled teeth to 0.67% in women with 13 or more teeth filled with amalgam. Analyses including the number of teeth filled with amalgam as a continuous variable indicated an increased risk of perinatal death by increasing number of teeth filled with dental amalgam (crude OR 1.065, 95% CI 1.034 to 1.098, p<0.001). After adjustment for potential confounders (mothers' age, education, body mass index, parity, smoking during pregnancy, alcohol consumption during pregnancy) included as categorical variables, there was still an increased risk for perinatal death associated with increasing number of teeth filled with amalgam (ORadj 1.041, 95% CI 1.008 to 1.076, p = 0.015). By an increased exposure from 0 to 16 teeth filled with amalgam, the model predicted an almost doubled odds ratio (ORadj 1.915, 95% CI 1.12 to 3.28). In groups with 1 to 12 teeth filled with amalgam the adjusted odds ratios were slightly, but not significantly, increased. The group with the highest exposure (participants with 13 or more teeth filled with amalgam) had an adjusted OR of 2.34 (95% CI 1.27 to 4.32; p = 0.007).

Conclusion: The current findings suggest that the risk of perinatal death could increase in a dose-dependent way based on the mother's number of teeth filled with dental amalgam. However, we cannot exclude that the relatively modest odds ratios could be a result of residual confounding. Additional studies on the relationship between exposure to dental amalgam fillings during pregnancy and perinatal death are warranted.

PubMed Disclaimer

Conflict of interest statement

I have read the journal's policy and the authors of this manuscript have the following competing interests: LB and GBL are employed by the Norwegian Dental Biomaterials Adverse Reaction Unit, which is funded by the Norwegian Ministry of Health and Care Services; no financial relationships with any organisations that might have an interest in the submitted work in the previous three years, no other relationships or activities that could appear to have influenced the submitted work.

Figures

Fig 1
Fig 1. Adjusted odds ratio and 95% confidence interval by number of teeth filled with amalgam.
Continuous exposure measure (a) and by exposure category (b).
Fig 2
Fig 2. Number of teeth filled with amalgam (mean and standard deviation) in the study cohort by year (n = 70,069).
Fig 3
Fig 3. Mean perinatal mortality (deaths per 1,000 births) by year for group 1, 2 and 3 countries (see text and S1 Table).
Data from Bio Intelligence Service and World Health Organization Regional Office for Europe.
See this image and copyright information in PMC

References

    1. Badenhorst W, Hughes P. Psychological aspects of perinatal loss. Best Pract Res Clin Obstet Gynaecol. 2007;21(2):249–59. 10.1016/j.bpobgyn.2006.11.004 . - DOI - PubMed
    1. Flenady V, Midd/leton P, Smith GC, Duke W, Erwich JJ, Khong TY, et al. Stillbirths: the way forward in high-income countries. Lancet. 2011;377(9778):1703–17. 10.1016/S0140-6736(11)60064-0 . - DOI - PubMed
    1. Clarkson TW. The three modern faces of mercury. Environ Health Perspect. 2002;110 Suppl 1:11–23. 10.1289/ehp.02110s111 ; PubMed Central PMCID: PMCPMC1241144. - DOI - PMC - PubMed
    1. Life Sciences Research Office (LSRO). Review and analysis of the literature on the health effects of dental amalgams Bethesda, MD: Life Sciences Research Office, 2004.
    1. Tobi H, Kreulen CM, Vondeling H, van Amerongen WE. Cost-effectiveness of composite resins and amalgam in the replacement of amalgam Class II restorations. Community Dent Oral Epidemiol. 1999;27(2):137–43. . - PubMed

Publication types