“…All studies 2,4,5,7,8 included at least one group of bis-acryl/bis-GMA 2,4,5,7,8 composite resins and one of an acrylic resin based on methacrylate (MMA), 4 polymethyl methacrylate (PMMA) 2,5,7,8 or poly ethyl methacrylate (PEMA). 2,4,7 One also included a resin based on urethane dimethacrylate (UDMA).…”