Engineering properties and performance of dental crowns

Area of Science:

• Biomaterials Science
• Dental Materials
• Mechanical Engineering

Background:

• Dental crowns are prosthetic devices used to restore tooth structure, requiring reliable fixation with luting cements.
• Luting cements bond crowns to prepared teeth, necessitating strong adhesion, minimal microleakage, and predictable failure modes.
• In vitro mechanical testing, including Weibull analysis, is used to assess crown survival probabilities and reliability.

Purpose of the Study:

• To evaluate the fracture toughness of luting cements and their interfaces with dentine.
• To explore methods for predicting the long-term performance of dental crowns based on material properties.
• To advance fracture mechanics testing for dental luting agents.

Main Methods:

• Mechanical testing of dental crowns using Weibull models to analyze failure load distributions.
• Fatigue testing and regression analysis to interpolate survival probabilities.
• Fracture toughness measurements using chevron notch short rod and short bar techniques for cements and cement-dentine interfaces.

Main Results:

• Conventional and resin-modified glass ionomer cements exhibit cohesive failure within thin interaction zones with dentine.
• Chevron notch techniques enabled the determination of fracture toughness for luting cement-dentine substrate interfaces.
• The study highlights the need for representative fracture experiments under mixed-mode conditions.

Conclusions:

• Predicting the long-term performance of dental restorations from short-term laboratory tests remains a significant challenge.
• Advanced fracture mechanics testing, including interfacial properties, is crucial for understanding luting cement behavior.
• Further development of mixed-mode fracture experiments is needed for more accurate performance prediction.