Bisphenol A concentration in human saliva related to dental polymer-based fillings

The aims of this study were to quantify salivary concentrations of bisphenol A (BPA) and to assess if presence of dental composite fillings is associated with higher BPA levels in saliva.

Twenty individuals with six or more tooth surfaces filled with polymer-based dental materials (composite group) and 20 individuals without any polymer-based materials (control group) were included in the study. Saliva was collected in polypropylene tubes and stored at -80 °C before analysis. Concentration of free (unconjugated) and total bisphenol A was determined by liquid chromatography/mass spectrometry (LC/MS). Values below limit of detection (0.1 ng/mL) were set to one-half of the limit of detection. Mann-Whitney U test (one sided; the Exact Tests Option in IBM-SPSS version 21) was used for the statistical analyses.

The concentration of BPA in saliva was very low. In the composite group, 8 of 20 samples had detectable concentrations of BPA. In the control group, 3 of 20 samples had detectable concentrations of BPA. Statistical analysis indicated that the concentration of unconjugated BPA was slightly higher in the composite group (p = 0.044) than in the control group.

Presence of dental composites may be associated with slightly higher concentration of unconjugated BPA in saliva. However, additional studies using sensitive analytical methods are needed before firm conclusions can be drawn. Influence from other factors, like food intake and time of the day for saliva sampling, must be considered.

The relative contribution of existing polymer-based dental fillings to total BPA exposure seems to be low.