Stress concentration in all-ceramic posterior fixed partial dentures

Two-dimensional finite-element analysis was used to study levels and distribution patterns of stress within three-unit f ixed partial dentures (mandibular first premolar to first molar) constructed of different materials (Type III gold alloy, Dicor, and In-Ceram) and with different connector heights (3.0 mm versus 4.0 mm). In the computer models, 10 MPa of stress was applied centrally to the prosthesis. Resultant von Mises stresses were concentrated within the connectors; the greatest stress occurred at the axial location of the connector. Stresses were 40% to 50% lower for 4.0-mm connectors. Patterns of stress distribution were similar for premolar and molar connectors. Stress levels within In-Ceram models were lower than for the other two materials and represented a lower percentage of the ultimate strength of the material. Based on a two-dimensional finite-element analysis model, In-Ceram would appear to be the best choice for posterior fixed partial dentures.