Concentration of Bisphenol A in Saliva and Urine Before and After Treatment With Polymer-based Dental Filling Materials

Bisphenol A (BPA) is a xenoestrogen which has been shown to cause abnormalities in sexual development and may lead to reproductive damage in animals. In epidemiological studies BPA has been associated with various health effects. The majority of dental plastic filling materials contain polymers synthesized from BPA. Whether BPA is released in vivo from polymer-based fillings and - if so, in what doses - is not sufficiently examined. Patients scheduled for regular dental examination at the public dental clinic, Bergen Downtown District, who needs therapy with dental polymer-based filling materials and is suitable for study (inclusion / exclusion criteria) will be informed about the project. If the patient wants to participate in the study, he/she will be given written information about the study and a consent form. It is emphasized that participation in the study is voluntary and the patient will have the opportunity to read the information at home, before the next appointment at the clinic. The clinical treatment of the carious lesion(s) will be performed according to standardized procedures and materials used at the clinic. After curing, the filling will be polished according to the standard procedures. The curing lamp will be controlled and documented weekly during the project period. All treatment sessions will be scheduled in the morning before 9 am. Questions regarding food intake and dental hygiene habits will be included in questionnaires answered during the study. Samples of saliva and urine will be collected immediately before filling placement and 1 hour, 24 hours and 1 week after treatment. A saliva sample will also be collected immediately after treatment. No food or drink intake is allowed after midnight before sample collection. Only tapped water is permitted. The sampling procedure will be controlled in advance, so that the risk of contamination of samples is minimized. After collection samples will be refrigerated and stored frozen at -80 °C until analysis. Bisphenol A in saliva and urine will be determined by liquid chromatography and mass spectrometry (LC-MS). The detection limit of the method is estimated at 0.1 ng BPA/ml. The study is approved by the Regional Committee for Medical and Health Research (reference number 2014/1529). Patients who participate in the project will have to collect saliva samples five times and urine samples four times, which involves extra visits to the clinic. The biomedical outcomes (concentration of bisphenol A in saliva and urine) will be assessed in a pre-defined group of individuals. The participants may be enrolled in the study if they fulfil the criteria (including need of a dental filling). The participants do not receive the intervention (placement of a dental filling) because they are enrolled in the study. Subjects in the study will receive the therapeutic intervention, but the investigator does not assign the intervention to the subjects of the study. Thus, the study may be described as an observational study.