Influence of elastic modulus mismatch between dentin and post-and-core on sequential bonding failure

Area of Science:

• Biomaterials Science
• Dental Materials
• Biomechanics

Background:

• Clinical failures of post-and-core restorations compromise tooth survival and oral function.
• Cement adhesion is a critical weak point in post-and-core restored teeth, influencing stress distribution upon failure.
• The mechanical behavior of these complex structures is not fully understood.

Purpose of the Study:

• To investigate the hypothesis that the elastic properties of post-and-cores affect cement failure processes in prosthetic-treated teeth.
• To analyze how different post-and-core materials influence stress distribution and adhesion failure.
• To understand the mechanisms leading to clinical failures in post-and-core restorations.

Main Methods:

• Utilized finite element analysis (FEA) to simulate sequential adhesion failure between dentin and cement.
• Employed the penalty function method to analyze stress during various bonding conditions.
• Observed failure patterns and stress distribution in dentin under different post-and-core materials.

Main Results:

• Initial cement failure occurred at the palatal crown margin irrespective of the post-and-core material.
• Distinct adhesion failure patterns between dentin and post-and-cores were observed, correlating with material elastic properties.
• Stress concentrations were identified at interfaces corresponding to adhesion failures, indicating localized damage.

Conclusions:

• Sequential cement adhesion failures between dentin and post-and-cores were successfully simulated using failure criteria.
• Local stress concentrations, causing severe dentin destruction, result from both post-and-core materials and their adhesive status.
• Nonlinear FEA modeling of complex structures with altered interfacial conditions can simulate clinical failures in post-and-core restorations.