A Critical Analysis of the Importance of Compaction-Pressure on the Dimensional Distortion of ZrO_2-Y_2O_3 Dental Prostheses

摘要

In this work, the effect of pressure and direction of compression in the shrinkage and flatness of ZrO_2-(Y_2O_3) dental ceramics were studied. Samples (40×15×15mm) were uniaxial cold pressed at different pressures ranging from l0MPa to 160MPa, and then pre-sintered for further cutting. For comparison, samples were also isostatically cold pressed at 300MPa. The pre-sintered samples were cut longitudinally and transversely to the direction of compression, with final thickness of lmm. Then the samples were ground and polished, and measured with a micrometer at different positions of the sample. After the measurements, the samples were sintered at 1530C-120 min, and again measures. The results indicate the effect of pressure decline in considerable amounts, up to pressures of about 80MPa. Above this value the differences in shrinkage and warpage are insignificant when compared to isostatically pressed samples.