The purpose of this study was to evaluate the shear bond strength of light-cured glass
ionomer cements to dentin surface according to curing time induced by argon laser.
In this study, 160 extracted human molars with sound crown were used. The dentin surface of these teeth were exposed with high speed diamond bur under water s,)ray and polished with 120, 320, 400, 800, 1200 grits sand paper.
160 extracted human molars were randomly assigned into four groups(coatrol, experimental 1, 2 & 3) with 40 teeth each. Control group used a visible light curing unit, XL 1000(3M Co., U.S.A) and experimental groups used argon laser(SPECTRUNI "m). And then each group subdivided into two groups(A, B) according to filling materials. Subdivided A group used Fuji H LC(GC Co., Japan), B group used Vitremer(3M Co., U.S.M.
The curing units and curing time of each group were as follows:
Control group visible light, 40 seconds
Experimental group 1 : argon laser, 10 seconds
Experimental group 2 argon laser, 20 seconds
Experimental group 3 : argon laser, 30 seconds
The glass ionomer cements were bonded to dentin surface of each specimen. The specimens were stored in 100% relative humidity at 370C for 7days. And then, the shear bond strength were measured by universal testing machine(Shimatzu Co. Japan) at cross-head speed of 5mm/min and 100kg in full scale and analyzed statistically.
The following results were obtained :
1. Experimental group 2-A showed the highest shear bond strength with 9.87 1.24 kgf and control group B showed the lowest shear bond strength with 4.08 t 0.78 kgf(P <0.01).
2. The Fuji H LC showed higher shear bond strength with 9.49 t 1.24 kgf than that of the Vitremer with 4.23 1.24 kgf. There was significant difference between Fuji II LC and Vitremer(p<0.01).
3. There was no significant differences among experimental groups according to curing time induced by argon laser.
4. There was no significant differences between control group and experimental groups according to curing units.
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