Impact strength, fracture toughness and hardness\ud improvement of PMMA denture base through\ud addition of nitrile rubber/ceramic fillers

摘要

Background/purpose: PMMA resin mostly used the fabrication of denture base by heatcuring\udtechnique. It has poor strength, including low impact strength and low fatigue resistance. In\udthis work the combination of nitrile butadiene rubber (NBR) with two types of ceramic fillers\ud(Al2O3 and YSZ, respectively) on the mechanical properties of denture base are investigated.\udMaterials and methods: The denture base composites were fabricated by incorporating PMMA\udpowder, 0.5 wt% of benzoyl peroxide (BPO), fixed at 7.5 wt% NBR particles and ceramic fillers\ud(fixed at 5 wt%) as powder components. In total, 180 specimens were prepared for all tests and\uddivided into 6 groups for each test (N= 10) coded G1–G6. Group 1 as the control group (without\udfillers) was mixed between PMMA powder and BPO; whereas the other five groups (G2–G6) were\udreinforced with NBR particles and different concentrations of ceramic fillers. The morphology of\udthe fracture surface of specimens was examined by Field Emission Scanning Electron Microscopy\ud(FESEM).\udResults: Statistical analysis, shows that the mean impact strength (IS) and fracture toughness (KIC)\udof control dentures when compared to reinforced PMMA at 7.5% NBR and 2.5% Al2O3/2.5%\udYSZ improved significantly (5.27± 0.21–10.25 ± 0.41 kJ/m2 and 1.60 ± 0.24–2.58\ud±0.30 MPa�m1/2, respectively).