[Three-dimensional finite element analysis of all-ceramic crowns of the posterior teeth].

The all-ceramic crown has been applied in clinical practice for its esthetic value and excellent biocompatibility. The purpose of this study was to examine the effect of different cervical marginal shapes on the stress distribution of all-ceramic crowns of the mandibular first molar by three-dimensional finite element analysis. The results showed that under vertical loading, the bearing compress stress on the occlusal region, the tensile stress concentration were observed at buccal cervical marginal of all-ceramic crowns; the stress at the surface of the crown was the highest, the stress inside the crown was higher than that inside the prepared teeth; the shoulder's stress value was lower than the chamfer's. These results lay the theoretic foundation for clinical application of all-ceramic crown, suggesting that the shoulder design should be recommended in clinical practice when the all-ceramic crowns are planned. The cervical thickness of the crown should be within 0.5-1.0 mm, and the crowns surface should be polished well to improve its resistance to fracture.