Understanding and enhancing the mechanical performance of bioinspired zirconia-based dental materials

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Oral disease such as tooth decay is one of the major healthcare challenges that affects over 40% of the world's population and over 30% of dentate adults in England. Such disease can lead to a loss of function in teeth that can impair diet and have undesirable consequences for general health. It can also lead to a loss of aesthetics in teeth, which adversely influences social activity of the patients. Both function and aesthetics can be restored with dental crowns (e.g. porcelain-veneered zirconia frameworks), which can also help prevent patients from experiencing pain, sensitivity and infection. Driven by the ageing population in the UK who need complex dental care to restore and maintain their teeth throughout their lives, as well as the fact that over 37% of dentate adults in England have one or more crowns, there has been a growing demand for patient specific dental restorative products (e.g. dental crowns) with increased longevity. Despite a continuous improvement in the mechanical performance, the conventional porcelain-veneered zirconia frameworks still suffer from a high failure rate (approximately 6-15% over a 3- to 5- year period). The primary failure mode of these dental crowns is near-interface chipping of the porcelain veneer, due to the loads that are applied to the chewing or grinding surface of the crown during mastication (referred to as occlusal loads). Failure of dental crowns can cause extensive discomfort to patients and have high cost implications for both patients and clinicians. To alleviate the problem, it is therefore highly desirable to develop novel porcelain-free zirconia-based dental restorative materials with significantly improved resistance to cracking. Inspiration for these composites can come from natural teeth, which have an intricate architecture giving them remarkable mechanical properties, especially the resistance to fracture - particularly in tooth enamel. Tooth enamel has been shown to have graded microstructure and extraordinarily strong interfacial bonding to the resilient supporting dentine. In this project, we propose to understand and improve the mechanical performance of novel zirconia-based composites with bioinspired functionally graded and textured microstructures. Our aim is to mimic the structure and remarkable mechanical properties of natural tooth enamel. The improvement of the mechanical performance will be based on a fundamental understanding of the role of bioinspired microstructural features in determining the mechanical properties, and how the properties can be enhanced by microstructural optimisation. To achieve this, we will develop and implement advanced micro-scale mechanical and structural characterisation techniques and micromechanical modelling. We will be working in close collaboration with academic and industrial collaborators and receive clinical input. The outcomes of this project will direct the manufacturing and processing towards biomimetic materials design and optimisation for the development cycle of the next generation dental products. Patients suffering from dental disease will benefit from this work through far-reaching improvements in the state of health, personal happiness and quality of life.