Survival Predictions of Ceramic Crowns Using Statistical Fracture Mechanics

Area of Science:

• Biomaterials Science
• Mechanical Engineering
• Dental Materials

Background:

• Dental restorations, particularly monolithic ceramic crowns, are susceptible to fatigue failure under masticatory loading.
• Understanding failure mechanisms is crucial for improving the longevity and reliability of dental prosthetics.

Purpose of the Study:

• To establish a survival probability methodology for interface-initiated fatigue failures in monolithic ceramic crowns.
• To compare the fatigue performance of different ceramic materials under simulated chewing conditions.

Main Methods:

• Developed a 3D finite element analysis model of a molar crown.
• Incorporated material properties and flaw distributions for fluormica (FM), leucite (LR), lithium disilicate (LD), and yttrium-stabilized zirconia (YZ).
• Simulated crown survival probability as a function of loading cycles using a fracture mechanics-based model.

Main Results:

• Weaker ceramics (FM, LR) exhibited lower survival rates compared to stronger ceramics (LD, YZ).
• Yttrium-stabilized zirconia showed a marginally better 10-year survival rate than lithium disilicate.
• Failure initiation was predicted at margins for LD crowns and occlusal areas for FM crowns.

Conclusions:

• The developed model provides insights into fatigue failure probabilities of ceramic dental crowns.
• Material strength and pre-existing surface flaws significantly influence crown survival under cyclic loading.
• The model highlights the importance of considering interfacial stresses for predicting crack propagation and failure modes.