In-Vitro Evaluation of the Cytotoxicity of Binders and Powder used in 3D Colour Printing of Maxillofacial Soft Tissue Prostheses

Purpose: The purpose of this study was to evaluate biocompatibility of the binders ‘ZB58’ and the starch powder ‘ZP15e’ used by the Z510 colour printer for printing soft tissue facial prostheses. Materials and Methods: Biocompatibility was investigated by testing four binders and the powder at three concentrations on two cell lines (ROS - osteoblasts and L929 - fibroblasts). The binders and the powder were exposed to the cells for 3, 5 and 7 days, after which the cells were treated with 10% Alamar Blue. Binder and powder toxicity was measured as a comparison against the uninfected media only cell control. Results: The Alamar Blue assays for the ROS and L929 cell line for all days no significant toxic effects were observed at lower binders and powder concentrations. However there was evidence of reduction in all cell vitality at higher concentrations and it appears to be more pronounced at seven days exposure Conclusion: The Alamar Blue assay highlighted the potential toxic effect of the four coloured binders and at less extent the powder used in the manufacture of soft tissue facial prostheses when used in high concentrations when applied on two types of cell lines used in this study (ROS and L929). This effect was most pronounced for the clear binder at seven days exposure. Clinical significance: Further work will need to be carried out to determine if the binder is able to leach out of the soft tissue prostheses at concentrations that may cause a local tissue reaction.