[The effect of the cementing material on the strength of the all ceramic crown].

On the assumption that the all ceramic crown was cemented on an abutment tooth, the effect of the cementing materials on the strength of the ceramic crown was analyzed using two-dimensional finite element technique. The results obtained were as follows: 1. When the compressive load was applied to the ceramics, the principal stress in the cementing material was compressive in the region of Young's modulus of the cementing materials 200-700 kg/mm2, but was in tension beyond it. 2. When the tensile load was applied to the ceramics, the principal stress in the cementing material was in tension, and decreased as Young's modulus of the cementing materials decreased. 3. When the adhesive effect of the cementing material was investigated with examining the presence of the crack between the ceramics and the cementing material, the principal stress in the ceramics increased as the crack propagated. 4. The creation and propagation of the crack, the increase of the principal stress in the ceramics and the destruction of the ceramics were suggested. 5. When the analyzed results were compared with the mechanical properties of the cementing materials from the point of view of the breaking strength, it was considered that the adhesive resin cement was favorable as the cementing material of the ceramic crown. And the Young's modulus of the adhesive resin cement was about 400 kg/mm2.