Bis-GMA monomer elution from modern resin-based composites - preliminary in vitro study

Abstract

Subject of research Resin-based composites (RBCs) are widely used in conservative dentistry. They have several posi-tive features, such as mechanical and aesthetic properties, and relatively low polymerization shrinkage. Nevertheless, the polymerization of modern composite materials results in a conver-sion rate of 55-80% and thus the presence of free monomers in the polymer network. Aim of the study The study aimed to quantify the release of Bis-GMA monomer from various composite materials as a result of elution under conditions similar to those in the oral cavity. Material and Methods The study evaluates the elution of Bis-GMA monomer from seven modern composite materials with different matrix compositions (Brillant Flow (I), SDR Plus Bulk Fill Flowable (II), Tetric EvoFlow Bulk Fill (III), Evetric (IV), Estelle Ʃ Quick (V), Filtek Z550 Nano Hybrid Universal Restorative (VI), Filtek Bulk Fill Posterior Restorative (VII)) into distilled water and 75% ethanol solution. The concentrations of the monomer were measured using the HLPC method (Agilent Technologies 1200 Series) after 24 h. Results None of the tested materials leached Bis-GMA monomer into the water solution after the 24-hour incubation period. The highest concentration of eluted Bis-GMA in 75% ethanol solution was found in samples V and II, with 43,93 µg*mL-1 and 34,84 µg*mL-1 respectively. In other samples, the concentrations observed were three to four times lower. Furthermore, a low concentration of eluted Bis-GMA could be found in materials VI and VII (1.43 µg*mL1 and 0,33 µg*mL-1 respec-tively), although not mentioned in the MSDS provided by the manufacturer. Conclusions The elution of the Bis-GMA residual monomer depended on the resin composition. The monomer was released in higher concentration from materials based on Bis-GMA/TEGDMA organic matrix composition. The addition of other, modern hydrophobic monomers reduced the release of Bis-GMA from RBC, regardless of the percentage of the inorganic filler ratio. Bis-GMA monomer elution depends on the solvent used. No Bis-GMA was detected in distilled water eluates. Even though the manufacturer specifies the composition of the RBC material, an independent assessment of its toxicity should be carried out.

Keywords

• hplc
• bis-gma
• bulk-fill
• monomer elution
• resin based composite