The purpose of this experiment was to determine the effects of etching with a Nd: YAG Laser on dentin, or porcelain surface on the bond strength with composite resin.
The dentin specimens were devided into the following 4 groups.
D1: No treatment
D2: Etched with 10% phosphoric acid
D3: Laser etchded with 1W, 20PPS
D4: Laser etched with 2W, 20PPS
The procelain specimens were devided into the following 4 groups.
P1: diamond roughened
P2: etched with HF acid
P3: Laser etched with 2W, 20PPS
P4: Laser etched with 3W, 20PPS
All specimens were veneered with resin.
One half of the specimens were stored in 37℃ water for one day and the other half were thermocycled 1000 times at temperature of 5℃ to 55℃ at 20 seconds intervals. After that, the bonding strength of composite resin to the dentin and porcelain
was
measured. The surface treated state and fractured state were observed with SEM.
@ES The following results were obtained.
@EN 1. In the dentin specimens, the bond strength of group D2 was higher than that of groups D1 and D3 in the case of the specimens stored in 37℃ water for one day, there was a statistically significant difference between group D2 and D1,
D3(P<0.05).
The bonding strength of the specimens that were thermocycled decreased in the following order: group D2, D4, D3 and then D1.
2. In the porcelain specimens, the bonding strength of groups P1, P2 were higher than that of group P3 in the case of the specimens stored in 37℃ water for one day(P<0.05).
The bonding strength of the specimens of being thermocycled decreased in the following order: group P2.P1.P4 and then P3.
3. The groups of high bond strength had a rougher surface and a high level of microporosity with SEM findings.
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