Mucotoxicity of dental composites on tissue engineered human oral mucosa

Objective: In a previous study a full-thickness tissue engineered human oral mucosal model was developed and characterised for biocompatibility assessment of biomaterials. The aim of this study was to evaluate the biological effects of three different composite resin systems on the three-dimensional oral mucosal model. Methods: Full-thickness oral mucosal models were engineered by air/liquid interface culture of human oral keratinocytes on a lamina propria composed of oral fibroblasts seeded into a cross-linked collagen-GAG-chitosane porous scaffold. Surface of the tissue models were exposed to three types of experimental composite resins: A TEGDMA-based, a UDMA-based, and a BisGMA/TEGDMA (80:20)-based composite resin for 24 hours. The response of the engineered oral mucosa to the test materials was assessed by histology, Alamar Blue cell viability assay and IL-1 beta release measurement by ELISA. Results: TEGDMA-based composite resin caused significant damage to the oral mucosal model compared to the other materials tested. There was epithelial damage with pyknotic nuclei and loss of normal epithelial cellular morphology and integrity. Statistical analysis by one-way ANOVA followed by Tukey's analysis showed that there was a significant decrease in the viability of tissue models after 24 hours exposure to TEGDMA-based composite resin. Also exposure to TEGDMA-based composite resin significantly increased the amount of IL-1beta released from the oral mucosal model from 5.13 ± 2.34 pg/mL to 28.76 ± 7.30 pg/mL. Conclusion: The 3-D oral mucosal model is more clinically relevant than monolayer culture of epithelial cells for the biocompatibility testing of dental materials and the results obtained from multiple-endpoint analysis of the oral mucosal model are more informative.