In vitro evaluation of gingiva-colored composite resins: cytotoxicity, apoptosis, and p53/NF-κB expression

This study evaluates the cytotoxicity, apoptosis, and expression of stress-related genes (TP53 and NF-κB) in response to gingiva-colored indirect composite resins used for veneering tooth or implant-supported prostheses or characterization of denture bases. A total of 120 disc-shaped specimens (2 mm thick, 10 mm diameter) gingiva-colored indirect composite resin specimens (Group A: Anaxgum-Anaxdent, Group B: Crealing Paste Gum-Bredent, Group G: Gradia Gum-GC, Group N: SR Nexco GUM-Ivoclar Vivadent) were prepared and divided into four groups (n = 10 per group). Surface wettability was assessed using water contact angle (WCA) measurements. Cytocompatibility was evaluated using the MTT assay with human gingival fibroblast (HGF-1) cells. Apoptosis and necrosis rates were assessed by flow cytometry, and TP53 and NF-κB gene expressions were analyzed via qRT-PCR. Data were analyzed using the Kruskal-Wallis test with Bonferroni-adjusted pairwise comparisons. The MTT assay revealed no cytotoxic effects, with all groups maintaining > 70% cell viability relative to the control. Exposure to the gingiva-colored composites did not result in significant changes in the rates of apoptosis and necrosis rates, indicating good cytocompatibility. TP53 mRNA expression levels did not differ significantly across groups. However, NF-κB expression was significantly downregulated in Group A (p < 0.001). These results indicate that the tested gingiva-colored indirect composite resins are cytocompatible with human gingival fibroblasts. While this suggests biocompatibility at the cellular level, further studies are necessary to confirm their overall clinical performance.