Effect of Extraction Media and Storage Time on the Elution of Monomers from Four Contemporary Resin Composite Materials

Introduction: The purpose of this study was to examine the effect of different extraction media, including culture media, as well as storage times on the elution of monomers from modern dental composites. Materials and Methods: Four contemporary composite materials were tested: (a) Clearfil Majesty Esthetic (Kuraray), (b) Esthet X (DENTSPLY), (c) Filtek Silorane (3M ESPE), and (d) Admira (Voco). Forty‑eight specimens were made. The specimens were stored in 1 ml of (a) artificial saliva, (b) Dulbecco`s Modified Eagle Medium (DMEM), (c) DMEM plus 10% fetal bovine serum (FBS), and (d) ethanol 75%. The specimens were analyzed after 24 hours and after 1 week of storage. HPLC Liquid Chromatography was performed to analyze the extracted solutions. The statistical package SPSS 18 was used for the statistical analysis of the results. Results: All the materials tested released monomers that were consistent with the base composition of their resin matrix. Bisphenol‑A (BPA) was detected in Clearfil Esthetic and EsthetX when ethanol 75% was used for storage. TEGDMA was released at a faster rate compared to the other monomers with most of the monomer eluted in the first 24 hours. The effect of storage solution and storage time on the elution of the same monomers varied between materials. Conclusions: There was a significant effect of time, storage solution, and material on the elution of the detectable unbound monomers. Unbound monomers were detected in culture media, which may lead to false‑negative results in cytotoxicity tests of resin composite materials. BPA was detected in two of the tested materials.