Polymer-based dental filling materials placed during pregnancy and risk to the foetus

Tooth-coloured polymer-based dental filling materials are currently the first choice for dental restorative treatment in many countries. However, there are some concerns about their safety. It has been shown that substances known as endocrine disrupters, which might pass through the placental barrier, are released from these materials within the first hours after curing. Thus, the placement of polymer-based dental fillings in pregnant women may put the vulnerable foetus at risk. Large epidemiological studies exploring the risk of having polymer-based dental materials placed during pregnancy are lacking. The aim of this study was to investigate the association between the placement of polymer-based dental fillings during pregnancy and adverse birth outcomes.

This study is based on data from the large Norwegian Mother and Child Cohort Study (MoBa). The information about dental treatment during pregnancy was obtained from questionnaires sent to the participating women during weeks 17 and 30 of pregnancy. Reported placement of "white fillings" was used as exposure marker for having received polymer-based dental filling materials. Only singleton births were included in the present study. Data were linked to the Medical Birth Registry of Norway. Logistic regression models that included the mother's age, level of education, body mass index, parity, and smoking and alcohol consumption during pregnancy were used to estimate the odds ratio (OR) and 95% confidence interval (CI). Different adverse birth outcomes were of interest in the present study.

Valid data were available from 90,886 pregnancies. Dentist consultation during pregnancy was reported by 33,727 women, 10,972 of whom had white fillings placed. The adjusted logistic regression models showed no statistically significant association between having white dental fillings placed during pregnancy and stillbirth, malformations, preterm births, and low or high birth weight.

In this study, women who reported white fillings placed during pregnancy had no increased risk for adverse birth outcomes compared with women who did not consult a dentist during pregnancy. Thus, our findings do not support the hypothesis of an association between placement of polymer-based fillings during pregnancy and adverse birth outcomes.