In silico fatigue performance of molars restored with full crowns under alternating cyclic loadings.

OBJECTIVE: In this study, a preclinical approach was used to analyze and directly compare the fatigue performance (fatigue life and damage percentage) and maximum principal stresses (Max. Ps) of prepared models treated with different materials and geometric parameters. METHODS: Four groups of preparative parameters (crown width, crown length, degree of polymerization and material) were selected, each with five variables. An alternating cyclic occlusal load with an amplitude of 300 N was applied to the ball part along the longitudinal axis. The fatigue properties of the preparations and Max.Ps were analyzed. RESULTS: A shoulder width of 0.8 mm, a shoulder height offset of 0.2 mm, a degree of polymerization of 5 degrees , and a crown material of ZC resulted in the smallest percentage of damage. In contrast, the effect of different modulus of elasticity (MOE) on Max.Ps was not significant (p = 0.609). CONCLUSION: The results suggest that the selection of larger modulus of elasticity MOE and larger Poisson's ratio material's, preparation of larger shoulder widths within safety, reasonable increase in crown length, and selection of larger degree of polymerization are favorable methods to protect the preparation.