| 3415 Effects of storage media on the physical properties of Fuji IX | ||
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K. KHOSRAVI1, H.C. NGO2, M. FRASER2, L.G. DO2, and G.J. MOUNT3, 1Isfahan University, Iran, 2The University of Adelaide, Adelaide, South Australia, Australia, 3The University of Adelaide, Australia Objectives: Surface hardness of glass ionomer cements is higher when stored in saliva than in distilled water (Okada 2001). It was suggested that this was due to the exchange of minerals between glass ionomer and saliva. This study was designed to test the effects of artificial saliva and its pH on the shear punch strength and surface hardness of Fuji IX (GC Corporation,Japan). Methods: A total of 168 samples were made by mixing capsulated Fuji IX at 4000cpm using an amalgam mixer (Optimix 100, Kerr,USA). The mixed cement was injected into a mould to create disks of 1.5mmx0.9mm. These were allowed to set between mylar strips for 5min, then at 25oC and 100% humidity for one hour. The samples were then divided into 7 groups with different storage conditions. A:100% humidity 1week, B:distilled water 1week, C:distilled water 3weeks, D:remineralising solution 1week, E:remineralising solution 3week, F:demineralising solution 1week and G:demineralising solution 3weeks. Both the re and demineralising solutions are saturated in regards to calcium and phosphate with the remineralising solution titrated to pH7 and the demineralising solution to pH4.5. All groups were kept at 37oC. The shear punch strength was measured using a Hounsfeld H50KM universal testing machine running at cross-head speed of 1mm/min. Vicker surface hardness was determined after 1w and 3w using a Leizt microindenter using 100g and 20sec static loads. Results: The shear punch strength for the different groups are listed below A:62.6MPa, B:68.4MPa, C:67.8MPa, D:71.9MPa, E:71.9MPa, F:73.5MPa, G:73.1MPa The surface hardness are A:72.3MPa, B:74.7MPa, C:74.1MPa, D:73.7MPa, E:77.5MPa, F:74.3MPa, G:81.4MPa There is statistically significant difference between the groups stored in remineralising and demineralising solutions and distilled water (P<0.05, using one-way Anova and Tukey tests). Conclusions: The physical properties of Fuji IX increased significantly over time when stored in solutions saturated with Ca and PO4. | ||
| Seq #312 - Cements, Bond Strength, Marginal Adaptation 11:00 AM-12:15 PM, Saturday, 9 March 2002 San Diego Convention Center Exhibit Hall C | ||
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