Salivary bisphenol A levels and their association with composite resin restoration

Composite resin has been increasingly used in an effort to remove minimal amount of tooth structure and are used for restoring not just carious cavities but also cervical abrasion. To synthesize composite resin, bisphenol A (BPA) is used. The aim of the study was to measure the changes in salivary BPA level related with composite resin restoration. ELISA was used to examine the BPA levels in the saliva collected from 30 volunteers whose teeth were filled with composite resin. Salivary samples were collected immediately before filling and 5 min and 7 d after filling. Wilcoxon signed-ranks test and linear regression were performed to test the significant differences of the changes in BPA levels in saliva. Before a new composite resin filling, there was no significant difference between with and without existing filling of composite resin and BPA level in the saliva was not correlated to the number of filled surfaces with composite resin. However, BPA level in the saliva increased to average 3.64 μg/L from average 0.15 μg/L after filling 5 min. BPA level increased in proportion with the number of filled surfaces. BPA level decreased to average 0.59 after filling 7 d. However it was higher than the BPA level before a new composite resin filling. Considering 50 μg/kg/day as the Tolerable Daily Intake of BPA suggested by European Food Safety Authority, the amount of BPA eluted in saliva after the composite resin filling is considered a safe level that is not a hazard to health at all.