Purpose: The purpose of this study was to determine the influence of margin design and taper abutment angle on the stresses developed in all-ceramic first premolar crowns. Materials and Methods: Four margin designs and three taper abutment angles were independently incorporated into models examined by finite element analysis. A 600-N force was applied vertically downward. Results: The taper abutment angle had a significant influence on the greatest peak tensile maximum principal stresses (
11) in the coping (16.8% change in stress for an 8-degree variation in taper angle). The margin design had significant influence on the highest peak tensile
11 in the dentin (60% difference in stress between designs) and lesser significance in the cement (30%). All calculated values of the highest peak tensile
11 were considerably lower than the fracture strengths of the respective materials in which the stresses resided. Conclusion: A smaller taper abutment angle and a larger chamfer radius (equivalent to the modified light chamfer) are recommended to reduce the magnitude of the greatest peak tensile
11 based on the finite element modeling conducted. Int J Prosthodont 2003;16:442–449.