ABSTRACT
Statement of problem. Information about the effect of different processing techniques on the marginal fit of lithium disilicate and zirconia-reinforced lithium silicate (ZLS) restorations is lacking.
Purpose. To evaluate the effect of different processing techniques on the marginal and internal fit of monolithic lithium disilicate and ZLS restorations.
Material and methods. Forty crowns were divided into 4 groups (n=10) according to the processing technique: IPS e.max CAD blocks (EC), IPS e.max Press ingots (EP), Celtra Duo blocks (CC); and Celtra Press ingots (CP). The dies and the ceramic crowns were scanned and then superimposed in a 3D engineering software. The 2D sections of the 3D superimposition analysis were used to measure the marginal and internal fit of each ceramic crown. The data obtained were statistically analyzed by using the Dunn post hoc test (α=.05).
Results. A statistically significant difference in the marginal discrepancy was found among all groups (P<.001); however, the difference between the EP and EC groups was not statistically significant (P>.05). A statistically significant difference in the internal discrepancy was found among all groups (P<.001); however, the difference between the EP and CP groups was not statistically significant (P>.05).
Conclusions. Monolithic zirconia-reinforced lithium silicate crowns processed by using the CAD-CAM technique showed significantly better marginal fit than other groups. Monolithic lithium disilicate crowns processed by using the CAD-CAM technique showed significantly better internal fit than other groups.