IADR Abstract Archives
Flexural Strength and Modulus of Aromatic and Aliphatic Urethane Dimethacrylates
The flexural strength (FS), flexural modulus (Ef), water sorption and water solubility of five diurethane dimethacrylate resins [two aromatic (UA and UB), a cycloaliphatic(UC), an aliphatic with pendant phenylether moieties (UD) and the commercially available aliphatic resin (UDMA)] were evaluated. Resins were filled (20% w/w) with silanated colloidal silica. Beam shaped specimens (25mm x 2mm x 2mm)(n=10) were prepared (LC 60 sec) and stored in 37°
C ±
2°
C distilled water and tested at seven days on an Instron utilizing a three-point loading jig at a 0.75 mm/min displacement rate. Disc shaped specimens (15mm x 1.0mm)(n=5) were light cured and desiccated to a constant mass. Specimens were then placed in 37°
C distilled water for 7 days, weighed, and re-desiccated to a constant mass. Mean values for flexural strength (MPa), flexural modulus (GPa), water sorption and solubility (mg/mm3) with standard deviations are listed below:
| Resin | FS | E(f) | WS (7 days) | Wsol (7 days) |
| UA | 112.9 (14.6) | 7.8 (3.9) | 27.5 (1.1) | 1.9 (0.4) |
| UB | 110.3 (6.5) | 7.6 (2.7) | 27.1 (1.1) | 6.5 (0.7) |
| UC | 120.3 (8.7) | 8.5 (5.0) | 28.7 (1.6) | 3.8 (0.6) |
| UD | 86.4 (7.2) | 5.6 (3.2) | 17.3 (0.8) | 5.4 (0.5) |
| UDMA | 105.5 (9.3) | 6.1 (1.9) | 27.6 (0.9) | 2.3 (0.5) |
ANOVA (p< 0.001) and Tukey’s Studentized Range Test (p< 0.05) indicated significant differences between resins for all four parameters. Resins with cyclic molecular backbones exhibited higher mean flexural strengths than non-cyclic.