Bio-inspired design of dental multilayers: experiments and model

Area of Science:

• Biomaterials Science
• Mechanical Engineering
• Dental Materials

Background:

• Natural teeth feature a gradient transition at the dentin-enamel junction (DEJ), unlike conventional dental restorations with distinct adhesive layers.
• This graded structure in natural teeth is crucial for stress reduction and structural integrity.

Purpose of the Study:

• To design and evaluate a bio-inspired, micro-scale functionally graded material (FGM) for dental applications.
• To mimic the stress-reducing properties of the natural dentin-enamel junction (DEJ).
• To improve the bonding and load-bearing capacity of ceramic-to-substrate dental structures.

Main Methods:

• Fabrication of a micro-scale, bio-inspired FGM structure.
• Experimental testing of the FGM under various loading rates.
• Development and application of a rate-dependent slow crack growth (RDEASCG) model for prediction.
• Simulations and analytical modeling to understand stress distribution.

Main Results:

• The bio-inspired FGM demonstrated significantly higher critical load capacities compared to conventional structures.
• The RDEASCG model accurately predicted the measured critical loads across different loading rates.
• The FGM effectively bonded a zirconia layer to a dentin-like polymer substrate.

Conclusions:

• Functionally graded materials offer a promising approach for creating more robust and bio-realistic dental restorations.
• Mimicking the natural DEJ structure can lead to improved mechanical performance and longevity of dental prosthetics.
• This research provides valuable insights for the future design of advanced bio-inspired dental multilayers.