چكيده به لاتين
Abstract
Glass ionomer cements are in powder-liquid system or powder that mix with water. The powder includes calcium fluoro alumino-silicate glass and liquid is polymer or copolymer of carboxylic acids. These cements are in 3 type: type one for sealing and luting casting components and fix them in the mouth, second type for restoration and third type for base and lining. Glass ionomers against their unique properties have a number of disadvantages such as susceptibility to dehydration, poor physical properties as a result of high solubility and slow setting rat, poor mechanical properties namely low fracture strength and toughness that limit them as a dental restorative material.
The object of this study is to improve mechanical properties and susceptibility to moisture of glass ionomer with changing composition of polymeric matrix by adding NVC and also adding Zirconia Nanoparticles to powder of Glass ionomer. In this regard terpolymer of polymeric matrix was synthesized with free radical polymerization. Then mechanically Zirconia Nanoparticles were added to Glass ionomer powder. After mixing powder and liquid of cement and preparation of samples, Flexural strength and Microhardness tests for investigation mechanical properties and Contact angle test for investigation susceptibility to moisture were done. The results for both Flexural strength and Microhardness showed that adding NVC and Zirconia improves both of these properties and the best result was obtained for a group that modification of liquid and powder were done simultaneous. About contact angle adding NVC reduced the contact angle of water and improved the wettability of cement but adding Zirconia reduced wettability in comparison with control group.
Keywords: Glass ionomer, Control group, NVC, Zirconia, Flexural Strength, Microhardness, Contact angle
