GENOTOXIC AND MOLECULAR STRESS EFFECTS OF DENTAL RESIN MONOMERS ON ORAL EPITHELIAL CELLS.

BACKGROUND: The dental materials based on resin substances release small amounts of their unreacted monomer components which result in continuous exposure of oral epithelial cells to these substances. The scientific community lacks sufficient knowledge about molecular reactions which occur before cells show toxic damage.

AIM: The research aims to determine how Bis-GMA and TEGDMA and UDMA and HEMA concentrations below cytotoxic levels affect oral epithelial cells through oxidative stress and DNA damage and changes in genes that control cell proliferation and apoptosis.

METHODS: The MTT assay helped researchers determine the specific concentration ranges which produced sub-cytotoxic effects. The DCFH-DA assay measured the amount of ROS which cells produced inside their cells. The alkaline comet assay was used to evaluate DNA damage while qRT-PCR analyzed the relative mRNA levels of BAX, BCL-2, p53, c-Myc and Cyclin D1.

RESULTS: The tested monomers at low concentrations did not affect cell metabolic activity but they all caused an increase in intracellular ROS levels. The two monomers Bis-GMA and TEGDMA generated the most significant increase in ROS levels among all tested compounds. The results showed oxidative imbalance because comet parameters showed increased DNA strand breakage and qRT-PCR results showed apoptosis-related gene expression with BAX and p53 showing elevated expression while BCL-2 levels decreased and c-Myc and Cyclin D1 showed no significant changes.

CONCLUSION: The research shows that oral epithelial cells experience oxidative and genotoxic stress when they encounter standard resin monomers at levels which do not result in major cell death. The research results confirm that additional studies need to investigate how biological responses develop from first molecular changes which occur when patients follow standard medical protocols.