Influence of coping design on stress distribution of posterior metal-ceramic crowns by three-dimensional finite element analysis

application/pdfObjectives To find the ideal form of coping for metal molar ceramic crowns, we evaluated their stress distributions under various loading conditions using three-dimensional finite element analysis. Materials and methods A three-dimensional finite element model representing a lower first molar was constructed. The model was varied to include one of three types of coping, the standard, butterfly, and flat types. A load of 600N, simulating the maximum bite force, was applied vertically to the crowns at the central occlusal surface and mesio-oc-clusal marginal areas. Loads of 225N, simulating masticatory force, were applied at a 45° angle to the tooth axis. Results In three of the simulation load tests, the maximum stresses were concentrated around the loading points on the porcelain and coping. The minimum tensile stress value was placed on the butterfly coping crown in the test simulating maximum bite force, when the load was applied to the mesio-occlusal marginal areas. Conclusion The butterfly coping design optimizes the stress distribution within copings and porcelain and enhances the structural strength of porcelain in metal ceramic crowns.journal articl