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Dental treatment may expose both the patient and the dental professionals to 2-hydroxyethyl methacrylate (HEMA). The compound is a monomer commonly used in resin-based dental materials. Incomplete polymerization of dental resin components can result in release of monomer to the oral cavity.

HEMA has also been shown to diffuse through dentin into the pulpal tissue. Possible adverse health effects to dental professionals due to inhalation of monomers have also been discussed as the monomer is measured in the air at dental clinics.

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DNA damage induced by HEMA in BEAS-2B cells.
(A) Control cells. (B) HEMA-exposed cells (24 hours with 5.4 mM HEMA).
The nucleus of the cells is stained green. Cells with DNA damages appear as “comets” in a fluorescence microscope using this method.

 

A recently published study from NIOM showed DNA damage in bronchial epithelial cells (BEAS-2B) exposed to HEMA. The Comet assay was used to detect DNA damage (Figure 1). When DNA damage occurs, a DNA damage response mechanism is initiated in the cell. This involves both cell-cycle arrest, allowing the cell to repair the damaged DNA before further replication, and activation of specific repair mechanisms. Consistent with DNA damage response, cell-cycle arrest and increased activation of the proteins p53, H2AX and Chk2 were also observed.

The latter are key proteins in a complex network that senses the DNA damage and activates the cellular response to the DNA damage. When DNA damage is too extensive and beyond repair, the cell undergoes a sequence of changes resulting in cell death, so called apoptosis, which was also found to be increased in the current study. However, if DNA repair fails and the cell survives, mutation, genomic instability and cancer initiation could arise.

In conclusion, the study showed that HEMA can induce DNA damage. Activation of key DNA damage response proteins is involved and apoptosis is induced. However, in what way HEMA induces DNA damage is still not known.


From
Ansteinsson V, Solhaug A, Samuelsen JT, Holme JA, Dahl JE.
DNA-damage, cell-cycle arrest and apoptosis induced in BEAS-2B cells by 2-hydroxyethyl methacrylate (HEMA).
Mutation research. 2011;723:158–164.

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NOIM Newsletter June 2013