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Purpose: This study examined the stresses developed during loading in a first premolar
metal-ceramic crown made of different metal cores, and used them to anticipate the
locations and form of the most likely failure modes. The maximum principal stresses in the
porcelain are indicators of fracture, and the von Mises stresses in the metal core are
indicators of the location of yielding. Materials and Methods: Two-dimensional
axisymmetric models with different core metals were analyzed using finite element
analyses. An axial load of 600 N was applied vertically downward, over a circular area
around the crown’s fissure. Results: The peak maximum principal tensile stress in the
porcelain existed on the surface of the crown, partially outside the cusp, with the greatest
peak in the gold-porcelain system (15.8 MPa). An inverse relationship between the peak
maximum principal tensile stress of each system and the elastic modulus of each core
material was found. According to evaluation of the critical flaw size for each system, even a
crack completely through the thickness of the porcelain was not critical. The maximum von
Mises stress existed in the metal coping, on the radial edge at the axial/occlusal line angle,
with the highest maximum in the nickel-chromium system (143.9 MPa). There existed a
proportional relationship between the maximum von Mises stress in each metal and their
respective elastic moduli. All maximums were well below the yield strength of the metal
alloys used. Conclusion: A greater understanding of the influence of an axial load on the
resulting stresses has been achieved, showing that the phenomena of fracture and yielding
are unlikely for the crown experiencing this axial load.
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