Marginal Fit Analysis of Different Ceramic Framework Materials

Objectives: To evaluate the marginal fit of Zirconia cores produced by a CAD/CAM system and a pressed Lithium Disilicate frameworks.
Methods: All copings were made with the same abutment (Globtek) prior fixed in an aluminum base. The IPS E-max Press (Ivoclar Vivadent) frameworks (n=10) and CAD/CAM Zirconia cores (n=10) Cercon (Dentsply) were all fabricated according to the manufacturer's instructions. Using an optical microscope at 50x magnification, the marginal frameworks adaptation were measured at twelve separate points, three points on each side (mesial, distal, buccal and lingual) in the same abutment. The results were submitted to Kolmogorov-Smirnov, t student and Friedman (p<0.05).
Results: The means for the marginal discrepancies of the Zirconia and Lithium Disilicate groups were found to be 106.0μm and 120.7μm, respectively. The CAD/CAM Zirconia cores obtained a lower misfit compared to Lithium Disilicate (p=0.041). The Zirconia cores obtained more regular values ​​of marginal fit in relation to Lithium Disilicate copings.
Conclusions: The Zirconia CAD/CAM system may produce more accurate adaptation than the Pressed Lithium Disilicate system. The technician’s skill and variation between the manufacturing process may be a determining factor influencing the accuracy of cores gap. However, both systems were within a clinically acceptable range.