Abstract: Objective: To study the influence of four kinds of post-cores on the color of Lava zirconia all ceramic system. Methods: An intact extracted maxillary central incisor was selected and excised 2mm coronal to the enamel-cementum. The tooth received endodontic treatment and root canal preparation. Four kinds of post-cores were prepared (n=10). Lava zirconia crowns were manufactured to fit the post-cores. The thicknesses of inner crown and enamel porcelain were 0.5 mm and 0.7 mm respectively. The color parameters (L^*, a^* and b^*) of the middle 1/3 of the crown were measured by the CM-700d spectrophotometry. The values of L^*, a^*, and b^* were compared by an ANOVA and a LED test, and the △E was calculated. Results: There were significant differences on the values of L^*, a^*, and b^* in four groups (P<0.05). The color difference of three teeth-color groups could not be identified by the naked eye (△E<1.5). While the △E values in the Co-Cr alloy post-cores group was beyond the clinical accepted level (△E > 2). Conclusion: The metal alloy post-core was not recommended for Lava zirconia crown, especially in the anterior area.

Key words: Zirconia , Post-core , All-ceramic, Color