Fit of zirconia all-ceramic crowns with different cervical margin designs, before and after porcelain firing and glazing

The purpose of this study is to investigate the fit of zirconia cores and all-ceramic crowns prepared with different cervical margin designs. The radius of curvature between the axial wall and the occlusal surface was set to 1 mm in an abutment using the cervical shoulder marginal design (S) and to 0.2 and 0.5 mm in abutments with round shoulders (0.2RS and 0.5RS, respectively). The internal gaps of the cores were 45-138 mu m (S), 41-141 mu m (0.2RS), and 43-133 mu m (0.5RS). The internal gaps of the all-ceramic crowns were 40-115 mu m (S), 45-113 mu m (0.2RS), and 42-126 mu m (0.5RS). There were no significant differences in one-way ANOVA for any region in any marginal design before and after firing the porcelain. The marginal gaps between the all-ceramic crowns and dies were 27 +/- 25 (S), 30 +/- 29 (0.2RS), and 24 +/- 27 mu m (0.5RS), again with no significant differences in one-way ANOVA.