Abstract:

Objective To study the differences in the marginal and internal adaptation of milled monolithic zirconia crowns with CAD/CAM fiber post-core, cast Ti post-core, prefabricated fiber post/resin core and dentin abutment group. Methods Thirty-two maxillary first molars in vitro were randomly divided into four groups(n=8):A-cast Ti post-core, B-prefabricated fiber post/resin core, C-CAD/CAM fiber post-core, D-dentin abutment. The crowns of Group A,B,C were cut 2 mm coronal to the cemento-enamel junction, and the post-and-core production was performed after complete root canal treatment, post canal and tooth preparation. The abutments of the four groups were in the same shape, and all of them were restored by milled monolithic zirconia crowns. Marginal adaptation and internal adaptation were examined using a light-body silicone and a 3D inspection software, Geomagic Wrap 2021 Qualify. The data were statistically analyzed with two-way analyses of variance. Results The milled monolithic zirconia crown in dentin abutment group had the best marginal and internal adaptation. The appearance of post-core would lead to the decrease of monolithic zirconia crown fitness. Cast Ti post-core had the greatest influence, and its marginal and internal fitness was the worst, followed by prefabricated fiber post-core and CAD/CAM, and there was no significant difference in marginal and internal adaptation between the two groups. Conclusion The marginal and internal adaptation of the four groups of monolithic zirconia crowns meet clinical requirements, and the appearance of post-core will affect the adaptation of monolithic zirconia crowns.

Key words: post-core, monolithic zirconia crown, marginal adaptation, internal adaptation