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Purpose: The aim of this study was to determine in vitro the internal and marginal fit of
zirconium dioxide ceramic copings manufactured using a recently introduced CAD/CAMbased
technique (Denzir). Materials and Methods: Two master models were produced in
metal, representing the maxillary right central incisor and first premolar. Two A-silicone
impressions were used for each of the master models, and from each of the impressions
five stone dies with the corresponding ceramic copings were produced, for a total of 20
copings. The A-silicone replica of the misfit of the ceramic coping to the corresponding
stone die and master model was sectioned buccolingually and mesiodistally. The
obtained sections were measured at occlusal, axial, and marginal locations under light
microscopy. Twenty-four measurements for each replica were made. The Student’s ttest
was used to detect significant differences between coping–stone die and coping–master
model misfits. Results: For any combination, the marginal fit was superior to the axial and
occlusal fit. In general, the misfit between the coping and the stone die did not differ
significantly from the misfit detected between the coping and the master model.
However, a better fit was recorded for the first premolar at the occlusal portion in the
coping–stone die combination compared to the coping–master model combination. The
mean marginal discrepancy between the copings and master models was clearly below
50 µm, with a range of 0 to 115 µm. Conclusion: The accuracy achieved by the Denzir
manufacturing process for the production of zirconium dioxide copings is well within the
range of clinical acceptability. Int J Prosthodont 2004;17:59–64.
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