The National Science Foundation has awarded Dr. Yu Zhang, an Assistant Professor of Biomaterials & Biomimetics, a three-year, $120,000 grant to develop design principles for formulating composite materials in layers that gradually evolve from the surface to the interior, a process known as functional grading. These materials could be used to increase load-bearing capabilities in a variety of medical, dental, and industrial applications.
Dr. Zhang's research is related to a three-year study that he began last year with the help of a $1.2 million grant from the National Institute of Dental and Craniofacial Research/NIH to reformulate zirconia as a glass-ceramic composite to increase its fracture resistance. This composite will have a predominantly glass surface with underlying layers that gradually become more densely packed with ceramic. Dr. Zhang predicts that a composite with glass-rich surfaces will be less susceptible to top-to-bottom fractures from direct contact with hard food as well as to ruptures that occur when the bottom of the restoration buckles under pressure, and that it will have aesthetics comparable to a porcelain-veneered zirconia restoration.
In the new, NSF-funded study, Dr. Zhang will look at the feasibility of applying design principles from the zirconia-glass composite to other kinds of functionally graded composites, metal-ceramic, ceramic-polymer, and multi-ceramic, among them. Using computer modeling as well as a load-bearing simulation machine to test prototype materials, he will develop a set of biomechanical guidelines that show, for example, how to make a support beam stronger through gradually adjusting the thickness of its surface and core. Ultimately, his findings could influence the design of items as small as a dental crown and as large as a construction support beam.