چكيده به لاتين
Due to their biocompatibility and desirable physical properties, Glass-Ionomer cements, are used widely in cilinical dentistry. This study looks at the effect of systhesis rout, as well as powder to liquid ratio on the cement’s setting time and compresive strength. To this end the glass powder portion was prepared by melting and sol-gel techniques. The amount of fluoride was 7 and 10% by mass in the powder formulation. Precursors used in the melting route were SiO2, Al2O3, CaCO3 and CaF2. In the sol-gel process Calcium and Aluminium Nitrate, TetraEtyl Orthosilicate, Phosphoric acid and Hexafluorosilicic acid were employed as starting materials. The resulting sample were analysed by performing XRD, SEM, FTIR, Thermal analysis and particle size distribiution experiments. Glass powder samples containing seven pecent by mass fluoride, were subjected to surface area experiments. After cements preparation using Commercial polyacrylic acid (powder:liquid ratios of 1:1, 2:1, 3:1 and 4:1) the samples were subjected to mictosrtucture and strength analysis. Cements prepared using melt and sol-gel glass powder containing 10% fluoride with powder to liquid ratio of 1:1 were studied for setting time behavior. The results show that the sol-gel process leads to crystallization of CaF2 particles and specific surface area higher than melting technic (~60 cm2/g). Furthuremore, the increase in F content in melting route caused a decrease in setting time and increase in the compresive strength of the cements. Melt sample containing 10% F at the powder: liquid ratio of 2:1 and setting time of around 10 mins and compressive strength of 75 MPa is considered to be the best sample in this study.
