Effect of addition ZrO2-Al2O3 nanoparticles mixture on some properties and denture base adaptation of heat cured acrylic resin denture base material


Background: The PMMA polymer denture base materials are low mechanical properties, adaptation of the denturebase to underlying tissue is important for retention and stability of denture. The aim of the study was toevaluate theeffect of mixtureZrO2-Al2O3 nanoparticles on impact strength, transverse strength, hardness, roughness, denture baseadaptation of heat cured acrylic resin denture base material.Materials and methods: One hundred (100) specimens were prepared, the specimens were divided into five groups(20 specimens to each) according to the test type, each group was subdivided in to two subgroups (control andexperimental) each subgroup consist of 10 specimens, the experimental group included mixture of 2% (ZrO2-Al2O3ratio2:1) by weight. Theimpact strength was measured by Charpy's impact testing machine, the transversestrength was measured by Instron testing machine while the hardness was measured byshore D durometer androughness was measured by Profilometer. Denture base adaptation was measured by digital microscope andevaluated by computerized tomography (CT).Results: Highly significant increaseofimpact and transverse strength, non-significant increase ofhardness, significantincrease ofroughness andreduction of denture base adaptation (measured at 3 point A, B and C) occurred inexperimental groupwhen compared to control group. CT evaluation, gap between the denture base and mastercast (control and experimental groups) increased from the anterior to posterior side of palate and from the alveolarridge to the mid palatal line.Conclusion: The polymer nanocomposites had mechanical properties higher than neat PMMA at same time lessdenture base adaptation