A comparative in vitro study on monomer release from bisphenol A‐free and conventional temporary crown and bridge materials

Abstract

Abstract This study aimed to investigate the release of common monomers from two conventional and two bisphenol A (BPA)‐free temporary crown and bridge materials. Cylindrical samples of all materials were prepared (N = 90; five samples for each material and cycle of analysis). All samples were immersed in high‐performance liquid chromatography (HPLC)‐grade water and incubated for 1 h, 12 h, 24 h, and 7 days in an incubation shaker at 37°C and 112 rpm. Extraction was performed in accordance with ISO 10993‐12. Eluted monomers were detected and quantified by HPLC coupled with ultraviolet–visible spectroscopy and mass spectrometry (HPLC‐UV/Vis‐MS). Analysis of BPA was performed by HPLC coupled with ultraviolet–visible spectroscopy (HPLC‐UV/Vis) and positive results were verified by HPLC‐tandem mass spectrometry (HPLC‐MS/MS). Neither bisphenol A‐glycidyl methacrylate (Bis‐GMA) nor BPA was quantifiable in any of the crown and bridge samples investigated in the present study. However, all samples contained triethylene glycol dimethacrylate (TEGDMA) and/or urethane dimethacrylate (UDMA) after 24 h of incubation. Statistical analysis showed that significantly more UDMA was released from the BPA‐free materials than from the conventional materials. All concentrations of UDMA measured were below the effective cytotoxic concentrations previously reported. However, for a few materials, especially BPA‐free temporary crown and bridge materials, the levels of UDMA were above previously reported potentially harmful concentrations for local cells. As BPA‐free materials were introduced as being more biocompatible than materials containing BPA, substitution of Bis‐GMA with UDMA should be further investigated.