Synthesis And Characterization Of Resin Modified Glass Ionomer Cements For Dental Restoration

Glass ionomer cement (GIC) is a kind of promising and novel dental restoration material.Combining the advantages of silicon cement, zinc phosphate cement and zinc polycarboxylate cement, it is widely used in the field of ClassⅤfilling, bonding, the hole base lining, the fissure sealant treatment, and etc. Compared with other dental restoration materials, there are many advantages for GIC, such as well bonding to dentine and enamel, anticariogenic properties due to release of fluoride, lower thermal expansion coefficient and good aesthetic property.However, because of its inferior mechanical properties, brittleness, releasing acidic molecule causing pulp allergy, it is not suitable for repairing great bite force placements and long term restoration. Therefore, improving their mechanical properties and biocompatibility have become the research hotspots.In this paper, novel polycarboxylates were synthesised by copolymerization or grafting and used as liquid parts of GIC. Effects of molecular weight, polymer content in the liquid composition, powder/liquid ratio, aging on compress strength (CS) and diametral tensile strength (DTS), working and setting time, water sorption and etc. were investigated. This study has prepared a kind of GIC which is hydrolysis resistant, not releasing acidic molecules, as well as having considerable mechanical strength. This method used in the study may provide a new direction for further research.The details and conclusions are described as follows:1. Firstly, Glycidyl methacrylate diethanolamine was synthesized and incorporated into polyacid main chains through ring opening reaction which would be used as liquid parts of GIC. The synthesized monomer and polymer were characterized by FTIR, NMR, and GPC. Secondly, many parameters such as initiator contents, molecular weight, liquid and powder ratio, polymer and water ratio of the experimental GICs were studied. The mainly testing and evaluation methods were compress CS and DTS, aging properties,working and setting time, water sorption and solubility, pH changing, microhardness and abrasion property, SEM, TG, and DSC.Besides, the curing process and mechanism of GICs were preliminary studed by FTIR. All the above results showed that the experimental GICs had considerable mechanical properties, good handling performance and presented excellent hydrolysis resistance and reduced acidic molecule leaching. In the end, it provided a a feasible approach for producing biocompatibility and comparable mechanical properties GICs.2. A kind of double bonds containing, lauryl methacrylate and glycidyl methacrylate modified polyacid were synthesized. FTIR, NMR, GPC were used as characterization and the feasibility of the polymer used as visible light cured GIC were studied.