Purpose: This study evaluated the effect of the incorporation of the antimicrobial monomer methacryloyloxyundecylpyridinium bromide (MUPB) on the hardness, roughness, flexural strength, and color stability of a denture base material.
Materials and methods: Ninety-six disk-shaped (14-mm diameter × 4-mm thick) and 30 rectangular (65 × 10 × 3.3 mm(3) ) heat-polymerized acrylic resin specimens were divided into three groups according to the concentration of MUPB (w/w): (A) 0%, (B) 0.3%, (C) 0.6%. Hardness was assessed by a hardness tester equipped with a Vickers diamond penetrator. Flexural strength and surface roughness were tested on a universal testing machine and a surface roughness tester, respectively. Color alterations (ΔE) were measured by a portable spectrophotometer after 12 and 36 days of immersion in water, coffee, or wine. Variables were analyzed by ANOVA/Tukey HSD test (α= 0.05).
Results: The following mean results (±SD) were obtained for hardness (A: 15.6 ± 0.6, B: 14.6 ± 1.7, C: 14.8 ± 0.8 VHN; ANOVA: p= 0.061), flexural strength (A: 111 ± 17, B: 105 ± 12, C: 88 ± 12 MPa; ANOVA: p= 0.008), and roughness (A: 0.20 ± 0.11, B: 0.20 ± 0.11, C: 0.24 ± 0.08 μm; ANOVA: p= 0.829). Color changes of immersed specimens were significantly influenced by solutions and time (A: 9.1 ± 3.1, B: 14.8 ± 7.5, C: 13.3 ± 6.1 ΔE; ANOVA: p < 0.05).
Conclusions: The incorporation of MUPB affects the mechanical properties of a denture base acrylic resin; however, the only significant change was observed for flexural strength and may not be critical. Color changes were slightly higher when resin containing MUPB was immersed in wine for a prolonged time; however, the difference has debatable clinical relevance.
© 2011 by the American College of Prosthodontists.