Clinical Significance
Not all mercury exposure is
Amalgam fillings contain about 50% mercury mixed with a powder form of mainly silver, tin, and copper. These fillings continuously release low levels of elemental mercury vapor into the oral cavity. It is inhaled and absorbed by the body. Mercury and silver particles can also be released through tooth wear and corrosion; these are generally swallowed. The amount of mercury released is dictated by the number of amalgam fillings present; mercury content in tissues correlates with the number of
The data were provided by the Norwegian Mother and Child Cohort Study (MoBa) and came from 69,474 pregnancies. Number of teeth with amalgam fillings and dental treatment, including new amalgam fillings placed or removed during pregnancy, were documented. The women received questionnaires at 17 and 30 weeks of gestation, with the data obtained linked to the Medical Birth Registry of Norway. The pregnancy outcomes evaluated were preterm birth, birthweight, stillbirth, and malformations.
Twenty-two percent of the women reported having no teeth with amalgam fillings and 16% reported more than 8 amalgam fillings. Mean self-assessed number of teeth having amalgam fillings in the entire sample was 4.4, with 5.6 being the mean number in patients who reported having amalgam fillings.
A total of 27,306 women (39% of the sample) reported consulting a dentist during their pregnancy, with 501 having new amalgam fillings placed and 2154 having amalgam fillings removed. For 79 women, the
No significant adverse relationships were noted between number of teeth with amalgam fillings and low birthweight, preterm delivery, malformations, stillbirth, or small for gestational age infants. It appears that having dental amalgam fillings placed or filled during pregnancy did not increase the risk of low birthweight, although girls of mothers who had amalgam fillings removed were at a slightly higher risk for being small for gestational age. Clinical Significance Not all mercury exposure is
Lygre GB, Haug K, Skjærven R, et al: Prenatal exposure to dental amalgam and pregnancy outcome. Community Dent Oral Epidemiol 44:442-449, 2016
Reprints available from GB Lygre, Dental Biomaterials Adverse Reaction Unit, Uni Research Health, Årstadveien 19, N-5009 Bergen, Norway; fax: +47 55 58 98 62; e-mail: [email protected]