Effects of Acetyl Tributyl Citrate on the Mechanical Properties, Abrasion Resistance, and Cytotoxicity of the Light-Cured 3D Printing Polyurethane Resins

The purpose of this study was to investigate the effects of acetyl tributyl citrate (ATBC) on the mechanical properties, abrasion resistance, and cytotoxicity of a polyurethane-based 3D printing resin for mouthguard applications. The synthesized polycarbonate-based polyurethane acrylate was formulated into digital light processing printing resins with 40 wt% triethylene glycol dimethacrylate, and different percentage of ATBC were added for further characterizations. The mechanical properties and abrasion resistance, ATBC migration, and the cytotoxicity of the resins were evaluated. The addition of ATBC in polyurethane-based resins enhanced the flexibility of printed resins. ATBC of 5-10% increased the toughness of printed resins, and the elongation at break. The printed resins with ATBC show higher hardness, comparing to conventional mouthguard materials, and have flexibility at meantime. All resins with ATBC showed no cytotoxicity and extremely low plasticizer migration, suggesting that ATBC have potential in long-term applicability. This is one of the few studies that shows the potential of adding ATBC into light-cure 3D printing resins. This study indicates that adding ATBC not only can tune the mechanical properties of 3D printing resins, but it can also showed low migration and did not increase the cytotoxicity in 3D printing resins.