1998 Fiscal Year Final Research Report Summary
SEM observation of Resin-modified Glass Ionomer Cement
| Project/Area Number |
09671967
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Conservative dentistry
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| Research Institution | Nihon University |
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Principal Investigator |
ANDO Susumu Nihon Univ.Sch.of Dent.Assistant Professor, 歯学部, 講師 (40120365)
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| Co-Investigator(Kenkyū-buntansha) |
IWASAKI Keisuke Nihon Univ. Sch.of Dent.Assistant, 歯学部, 助手 (00291708)
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| Project Period (FY) |
1997 – 1998
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| Keywords | Resin-modified glass ionomers / Self etching primer / Enamel bond strength / SEM Observation / Thermal stress |
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| Research Abstract |
Resin-modified glass ionomer cement (RGIC) is said to be inferior compared to resin cements on bond strength.
The aim of this research project was to evaluate the effect of with self-etching primers on RGIC, by evaluating shear bond strength and comparing the SEM interfacial morphology. A RGIC used was Fuji ionomer type II LC (GC), and a curing unit GC New light IILC (GC) was employed. An experimental Self-etching primer (GC) composed of bis-metacryloxyetyl phosphate (Bis-MEP), 2-hydroxyethyl methacrylate (HEMA), comphorquinoe, acetone and water as solvent. Acetone content of self-etching primers was ranged of 0,10,20,30,40 and 50 wt%. Bovine enamel ground with #600 SiC paper was treated with self-etching primers, Cavity conditioner (GC) and Dentin conditioner (GC). Cement was condensed into a vinyl mold _4x2mm) put on the treated enamel surface and light activated. The shear bond strength tests were carried out using a universal testing machine (Type 4204, Instron) at a crosshead speed
… More
of 1 .0mm/min after 24 hours of storage in 37* distilled water. After bond strength testing, the fractured specimens were examined in an optical microscope at a magnification ofxl0 to define the location of bond failure. Treated enamel surface was observed by SEM (JSM-5400, JEOL) and surface roughness (Rz value) was measured by the Image analyze system (MP-45200, JEOL).
The result were as follows :
1. The enamel bond strengths were significantly increased with self-etching primer treatment compared with dentin conditioner and cavity conditioner treatments.
2. The enamel bond strength decreased when the thermal stresses was added and the highest bond strength was obtained when the primer containing Bis-MEP was used.
3. The fracture mode of Fuji II LC was found to be adhesive at the enamel interface and partially cohesive in -the cement. Cohesive failure in the cement tended to increase with decreasing acetone concentration of the self-etching primers.
4. With the SEM observations of primed enamel surface, more clearly and deeper etching patterns were observed when the acetone concentrations were decreased.
5. The SEM interfacial morphology using of the self etching primers resulted in the sallow etching patterns compare with conditioner such as 10 wt% and 20 wt% polyacrylic acid. Less
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