Effects of dental resin components on vascular reactivity

The frequent use of resins in dentistry has raised the question of their compatibility with oral tissues. The present study was undertaken to determine the effects of the resin components methyl methacrylate (MMA), hydroxyethy1 methacrylate (HEMA), and triethylene glycol dimethacrylate (TEGDMA) on the reactivity of blood vessels using the isolated rat aorta as a tissue model. MMA, HEMA, and TEGDMA caused endothelium-dependent and -independent relaxation of rat aortic rings in a concentration-related manner. The endothelium-dependent responses of the tissues to all the resins were significantly attenuated by N-nitro-L-arginine methyl ester (L-NAME), indicating the involvement of nitric oxide. The vasorelaxant effects of both MMA and TEGDMA on the intact and denuded aortae were markedly inhibited by indomethacin, providing evidence for the role of prostanoids in these responses. Glybenclamide selectively attenuated TEGDMA-induced relaxation of the tissues with and without endothelium to a similar extent, suggesting the activation of vascular smooth muscle K_ATP channels by this resin. It is concluded that MMA, HEMA, and TEGDMA interfere with the function of blood vessels by inducing vasorelaxation via different mechanisms, which, depending upon the type of resin, may at least involve the release of nitric oxide and prostanoid(s), and the activation of smooth muscle K_ATP channels. These phenomena may play a role in tissue homeostasis and certain pathophysiological conditions associated with the application of resin materials to the oral environment.