Stress analyses applications on all-ceramic crowns with different designs

Different studies available in literature regarding the analysis of all-ceramic restorations failures, investigated several parameters involved on the tooth structure restoration complex, in order to improve clinical performances. Some of the parameters, like the framework design, are technique-sensitive during the manufacturing of the restorations and can easily influence the failure rates and fracture modes of final restorations. The goal of this study was to investigate the stress distributions of zirconia all ceramic crowns with different designs, using varied stress distribution analyses. A static structural analysis was performed. Equivalent stresses were recorded in the tooth structures and in the restoration for all designs. Since ceramic materials exhibit brittle behavior, the first principal stress criterion was adopted to compare the stress values and distribution with those obtained for the first simulations. Under the same loading conditions, the stress distribution patterns for the zirconia all-ceramic crown using differential stress analyses exhibited similarities. The stress values are lower for the maximal principal stresses in all cases. The present study suggests that varied simulation methods are promising to assess the biomechanical behaviour of all-ceramic systems and first principal stress criterion is an alternative for ceramic materials investigations. Key-Words: zirconia framework, ceramic veneer, crown, molar, simulation methods, finite element analysis, stresses.