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Department of Biomedical Engineering


Devendra Bajaj, Ph.D.
Postdoctoral Research Associate
Department of Orthopaedics, UMDNJ-NJMS


Tooth: A tough natural biocomposite


The structural integrity of load bearing (i.e. hard) tissues of the human skeleton and teeth is important for healthy living. With this in mind, there is significant interest in understanding the response of mineralized tissues to the applied loads (cyclic or sustained) encountered in function. Unlike bone, tissues of the human tooth cannot undergo remodeling i.e. cannot repair damage. Therefore, tooth tissues must achieve resistance to crack growth by the arrangement of their organic and inorganic constituents into densely packed hierarchical structures. This talk will focus on the mechanistic aspects of crack growth in tissues of the human tooth (i.e. enamel and dentin) and establish the importance of their microstructure.

Novel experimental techniques were used to enable stable crack extension in tooth tissues and the fatigue crack growth and fracture toughness properties were quantified. Results showed that both enamel and dentin enroll a combination of extrinsic and intrinsic toughening mechanisms that resist crack extension and impart toughness. However, the extent of toughening and contribution from individual toughening mechanisms is significantly influenced by age and microstructure of the tissue. Results from this work have implications for the development of new bio-inspired composites and ceramics for engineering and biomedical applications. Finally, the talk will provide an overview of the projects that are on-going in our lab at UMDNJ.