Cell Biological Consideration of the Mechanism Underlying Polymethyl Methacrylate (PMMA) Dental Resin Cytotoxicity in Oral Mucosal Cells

Abstract

Purpose: Purpose: The purpose of this study was to determine the potential role of oxidative stress in generating cytotoxicity of self-curing polymethyl methacrylate (PMMA) dental resin to oral mucosal cells and to understand its cellular mechanism.
Methods: Rat palatal gingival tissue-derived oral mucosal cells were seeded on self-curing PMMA-based dental resin or on a culture-grade polystyrene dish. A cell viability test and detection of apoptotic biochemistry markers using a flow cytometer, total concentration of glutathione (GSH) colorimetry, and fluorescent quantification of intracellular reactive oxygen (ROS) were performed at 24 hours after seeding.
Result: Only 0.2% of the oral mucosal cells were viable on the PMMA dental resin 24 hours after seeding compared with 85% or more on polystyrene. The cells on the PMMA resin exhibited strong positiveness of molecular markers indicative of cell membrane breakdown and apoptosis. Moreover, substantial elevation of intracellular ROS elevation and a decrease of total GSH concentration were found in the cells on the PMMA resin.
Conclusion: Considerable cell death characterized by a large increase of active caspases and cell membrane collapse was induced in palatal tissue-derived oral mucosal cells seeded on auto-polymerized PMMA-based dental resin. It was suggested that oxidative stress contributed to the cell death. These results help to clarify the mechanism underlying the cytotoxicity of PMMA-based dental resin to oral mucosal cells.