Post-Process Cytotoxicity of Resins in Clear Aligner Fabrication

This study aimed to evaluate the cytotoxicity of two resin materials, Tera Harz TC-85 DAC and Clear-A, along with the effects of two different post-printing protocols applied to Clear-A. Samples were produced using the Ackuretta Sol printer. The following three groups were formed based on the resins used and the post-curing methods applied: Group 1: Tera Harz TC-85 DAC resin + Tera Harz Cure; Group 2: Clear-A resin + Curie machine; and Group 3: Clear-A resin + Tera Harz Cure. All samples were sterilized in 70% ethanol for 5 min, rinsed with sterile deionized water, and incubated in Dulbecco's Modified Eagle Medium at 37 °C for 72 h. Cytotoxicity assessment was performed by the XTT and RTCA methods using the human gingival fibroblast cell line. According to the XTT assay, undiluted resin extracts exhibited approximately 75-80% cell viability at 24 h, while further dilutions resulted in a viability exceeding 90%. No significant differences in viability were observed among the groups at any dilution at 48 and 72 h. The xCELLigence RTCA results aligned with the XTT findings, showing a transient decrease in cell viability within the first 24 h, followed by continued cell growth. This study demonstrated that extracts from all tested 3D-printed resins exhibited biocompatibility with human gingival fibroblasts. These findings support their potential for further applications in the dental and biomedical fields.