Effect of Cement Space on the Marginal Adaptation of Monolithic Zirconia Crowns

To evaluate effect of cement space on marginal fit of monolithic zirconia crowns after sintering, glazing, and cementation.

Molar typodont teeth were prepared to receive crowns, and were scanned with a laboratory scanner to generate virtual dies. Crown design was planned with the CAD software with a simulated cement space of 60 μm or 80 μm. Zirconia crowns for the 60 μm and 80 μm groups were milled from zirconia discs. Milled crowns were sintered, glazed, and cemented. Marginal discrepancy was measured after sintering, glazing, and cementation. Measurements were carried out under 200X magnification, and data obtained were statistically analyzed.

Increasing cement space from 60 to 80 μm resulted in a non-significant decrease in marginal discrepancy. Marginal discrepancy was the lowest in the post sintered specimens, and increased significantly after glazing and cementation in both the groups.

It was concluded that the glazing and cementation procedures significantly increased the marginal discrepancy. Increasing the cement space resulted in an insignificant decrease in the marginal discrepancy.

The results of this study suggest that 60 μm of simulated cement space is recommended for achieving clinically acceptable marginal fit of the monolithic zirconia crowns.