Evaluation of Marginal Adaptation of Zirconia-Based All-Ceramic Copings

Objectives: The aim of this in-vitro study was to evaluate the influence of the luting space settings and the cement types on the marginal fit of Zirconia-Based Copings produced using a Cerec3-system.

Methods: The investigation was performed on a metal master model, which representing the mandibulary left first molar. Optical impression was taken directly from the master model, four conditions were established by combining two different setting of luting space 100µm, and 50µm with two types of cements (a– zinc phosphate, b– Panavia21). A total of 20 copings specimens were milled using Vita YZ blanks, 5 pieces for each condition. The samples were embedded in acrylic resin and then sectioned in the midpoint of each surface using a diamond saw. Marginal discrepancy and width of the marginal and internal gap were measured with a Light microscope. 82 measurements were made for each coping.

Results: One way ANOVA showed significant difference between the results. The mean values of seating discrepancy, marginal and internal fit for the copings are summarized in the following table.

MD: marginal discrepancy, MG: marginal gap, IG: internal gap.

Conclusions: The precision of marginal fit of copings were milled with 100µm luting space were better than those milled with 50µm luting space. The fit of copings cemented with adhesive cement was better than those cemented with zinc phosphate cement.