In vitro comparison of the cytotoxicity and water sorption of two different denture base systems

Purpose: Denture base resins have the potential to cause cytotoxicity in vivo, and the mechanical properties of resins are affected by water sorption. There is a correlation between residual monomer and water sorption. Thus, the purpose of this study was to evaluate water sorption and cytotoxicity of light-activated urethane dimethacrylate (UDMA) denture base resin compared to a conventional heat-activated polymethyl methacrylate (PMMA) resin.

Materials and methods: Two denture base resins, heat-activated PMMA (Meliodent) and light-activated UDMA (Eclipse), were used in this study. Cytotoxicity (5 × 1 mm(2) ) and water sorption (1 × 1 mm(2) ) specimens were made following the manufacturers' instructions (n = 10). Cytotoxicity tests of denture base resins were performed according to ISO10993-5:1999, and water sorption was evaluated according to ISO 1567:1997. ANOVA tests were employed for evaluating data (α = 0.05).

Results: There was no cytotoxic effect in either the PMMA or UDMA group. In addition, contrary to short-term water storage, a significantly lower water sorption value was shown for UDMA resins compared to PMMA resins in both 3- and 6-month storage periods (p = 0.043 and p = 0.002, respectively).

Conclusion: The tested denture base materials adhered to the ISO standards for both cytotoxicity and water sorption. The cytotoxicity of the light-activated UDMA resin tested was statistically similar to that of the heat-activated PMMA resin; however, the UDMA resin exhibited decreased water sorption in long-term water storage.