Assessment of genetic damage by methyl methacrylate employing in vitro mammalian test system.

Methyl methacrylate (MMA) is a volatile liquid widely used in the manufacture of acrylic polymers. In modern dentistry, MMA is the mainstream material in denture bases. MMA has been implicated as primary irritant and sensitizer, which can cause allergic eczematous reaction on the oral mucosa as well as skin. To date, there is growing concern that MMA may produce genetic damage by inducing mutation. In this study, colony forming efficiency, DNA synthesis, and cytogenetic assays were performed to investigate the adverse effects of MMA in cultured CHO cells. MMA was found to decrease colony formation in a dose- and time-dependent manner (P<0.05). MMA also inhibited DNA synthesis in a dose-dependent manner (P<0.05). The chromosome aberrations induced by MMA were the chromatid-type aberrations in the treated cultures. Moreover, the gaps and breaks were the most common type of aberrations observed. The sister-chromatid exchange frequencies were found to increase in the concentration of MMA. In this study, MMA was found to be not only a cytotoxic agent but also a genotoxic agent. The effects observed following treatment with low dose for longer duration is of relevance to the condition of the oral mucosa of the denture wears. Denture base resin could constantly release MMA extended periods, possibly causing moderate toxic reactions and possibly contributing to adverse effects on the mucosa.