1996 Volume 40 Issue 1 Pages 83-89
On the assumption that porcelain laminate veneer crown had been bonded to the abutment tooth with the light-curing luting material, setting characteristics of four light-curing luting materials were evaluated for linear shrinkage from the start of exposing, water absorption, Vicker's hardness and compressive strength after exposing the materials to visible light.
The results were as follows:
1. The light-curing luting materials rapidly shrank as soon as exposed to light passing through a cover glass or a plate made of porcelain. When exposed to light through the laminate veneer plate, the shrinkage of materials was less thanthat of materials exposed to light through a cover glass. The result suggested that the curing process was delayed because of a shade effect of the laminate veneer plate.
2. The compressive strength was shown to have a tendency to increase with the elapse of time. The compressive strength of luting materials storedin air at 37°C was larger than that of materials immersed in distilled waterat 37°C, and such a tendency was remarkable from 1 to 4 weeks after exposing.
3. The values of Vicker's hardness of light-curing luting materials were almost the same from 1 to 4 weeks after exposing, and the hardness values of the materials in air at 37°C was larger than those of materials immersed in distilled water at 37°C.
4. The amounts of water absorption (wt%) increased rapidly after the luting materials were immersed in distilled water at 37°C, but were hardly increased 8 weeks after exposing the materials to visible light.
