Flexural and Surface Properties of PMMA Denture Base Material Modified with Thymoquinone as an Antifungal Agent.

PURPOSE: To evaluate the effect of addition of different concentrations of thymoquinone (TQ) on the flexural strength, elastic modulus, surface roughness, and hardness of PMMA denture base material. MATERIALS AND METHODS: A total of 160 rectangular specimens were prepared from heat-polymerized acrylic resin, with dimensions of 65 x 10 x 2.5 mm(3) for flexural strength testing and 10 x 20 x 3 mm(3) for surface property testing. The specimens were divided into eight groups of 20 specimens: one control group without addition of TQ and seven test groups prepared by adding TQ to acrylic powder in concentrations of 0.5, 1, 1.5, 2, 2.5, 3, and 5 wt%. The polymer was added to the monomer before being mixed, packed, and processed using the conventional water bath method. A universal testing machine was used to measure flexural strength and elastic modulus. A profilometer and a Vickers hardness tester were used to measure surface roughness and hardness, respectively. One-way ANOVA and the Tukey-Kramer multiple-comparison test were used for statistical analysis, with statistical significance at p </= 0.05. RESULTS: Addition of TQ to PMMA denture base material significantly decreased flexural strength and elastic modulus at high concentrations (p < 0.01), while no significant differences were observed at low concentrations (0.5%, 1% TQ) in comparison with the control group. At high TQ concentrations, surface roughness increased while hardness decreased (p < 0.0001), and no significant differences were observed at low concentrations (0.5%, 1% TQ) in comparison with the control group. The most favorable addition values were 0.5% and 1% TQ in all TQ groups. CONCLUSIONS: Addition of TQ did not affect the flexural and surface properties of PMMA denture base material at low concentrations (0.5%, 1% TQ) and could be incorporated into PMMA denture base material as an antifungal agent.