Effect of internal coloring treatment on the marginal and internal fit of monolithic zirconia crowns: an in vitro study

sal reduction of 2.0 mm, axial reduction with a 1.0-mm offset, a 6 taper, and a chamfer margin for a monolithic zirconia crown.Then, a duplicated epoxy die was fabricated.According to the internal coloring treatment, the zirconia specimens were classified into the nontreatment (NT) group, DMAX white coloring liquid (DT) group, and Kuwotech esthetic liquid (KT) group.The internal data from all crowns were superimposed on the master die file using the "best-fit alignment" method with three-dimensional analysis software.The one-way analysis of variance and Tukey's honestly significant difference test were performed (corrected error level=0.05). Results:The gap in the DT and KT groups was significantly larger than that in the NT group (p<0.05). Conclusion:Within the study limitations, although the adaptation varied with the internal coloring treatment, the marginal and internal fits of the monolithic zirconia crown using the inner coloring technique fell within the range of clinical acceptance.