The Effect of Different Marginal Configurations and Scanning Powders on the Accuracy of the Marginal Adaptation of Zirconia Crowns

Objectives: The purpose of this study was to compare the effect of finish line design and imaging materials on marginal adaptation of zirconia crowns.

Methods: Two different marginal configurations were tested (1mm chamfer, 1.5 shoulder) and three different types of imaging materials (3M high resolution powder, Vita powder spray, Sinbrio scanning paint) in various permutations. The sample size was determined to be 18 per group (n=18). Two typodonts were prepared and scanned using the 3M True Definition scanner and milled. A total of 108 zirconia crowns were milled. Finally, the replica technique and a high magnification microscope 92X were used to measure the marginal gap.

Results: The means (standard deviation) for each group were 13.04 (1.66) μm for the chamfer and 3M powder group; 12.34 (1.77) μm for the chamfer and vita powder spray group; 12.45 (2.01) μm for the chamfer and Sinbrio scanning paint; 11.63 (1.25) μm for the shoulder and 3M powder group; 12.70 (1.43) μm for the shoulder and vita powder spray group; and 12.05 (2.69) μm for the shoulder and Sinbrio scanning paint group. The difference between marginal preparation designs was not statistically significant (p = 0.180), nor was the difference among imaging materials (p = 0.826).

Conclusions: There was no significant difference between the finish line designs utilized and the types of imaging materials tested on the marginal adaptation of zirconia crowns.