Objectives: The purpose of this study was to evaluate early flexural strength (FS) and surface hardness (Vickers hardness number, HVN) of a trial glass ionomer cement (GIC) for anterior restoration, FujiVIIIGP(VIIIGP, GC Corp) and FujiII(FII, GC Corp). VIIIGP is resin-reinforced GIC setting without light curing, and is improved on FII with respect to aesthetic, mechanical properties and setting characteristics.
Methods: The materials were mixed according to the manufacturer's instructions and placed into a mold (FS:diameter 3mm x length 20mm, HVN:diameter 5mm x height 1mm). The specimens were stored in a chamber at 37 centigrade degree and 100%RH. Then, the FS and the HVN of VIIIGP and FII were measured 10 minutes, and 24hours after the mixing.
|
VIIIGP |
FII |
|
|
FS (MPa) After 10min |
44.5 (4.3) |
7.9 (0.7) |
|
FS (MPa) After 24hrs |
48.9 (3.9) |
19.2 (2.6) |
|
HVN After 10min |
50.0 (3.6) |
27.8 (1.7) |
|
HVN After 24hrs |
57.5 (5.1) |
56.8 (1.9) |
( ):S.D.
Results: Comparing extracts by means of t test showed that both the FS and the HVN of VIIIGP after 10minutes were significantly higher than those of FII (p<0.01). The FS of VIIIGP after 10minutes reached 91% of that after 24hours, while the FS of FII after 10minutes was 41% of that after 24hours. The HVN of VIIIGP after 10minutes reached 87% of that after 24hours, while the HVN of FII after 10minutes was 49% of that after 24hours.
Conclusion: It was concluded that VIIIGP has the feature of a rapid development of mechanical properties compared to that of FII, therefore VIIIGP is clinically very effective.