Fitness of Zirconia all-ceramic crowns with different cervical margin forms

Abstract

The purpose of this study was to evaluate the marginal and internal fitness of zirconia all-ceramic crowns. Three brass dies were prepared with the following cervical margin forms: a shoulder and two types of rounded (curvature radius: 0.2 and 0.5 mm) shoulder preparations. Five crowns for each type of die were fabricated using the CAD/CAM system. The fitness was evaluated with a replica technique using silicon impression materials. The mean gap dimensions and standard deviations at the margins were 36 ± 32 µm for the shoulder, 27 ± 29 µm for the 0.2 mm rounded shoulder, and 41 ± 33 µm for the 0.5 mm rounded shoulder. There were no significant differences among the three groups regarding marginal fitness. The zirconia all-ceramic crowns made using the CAD/CAM system showed clinically acceptable marginal fitness.