Abstract
Dental caries is one of the most prevalent yet preventable oral conditions that affects 31% of UK adults as well as 46% and 34% of 15- and 12-year-olds, respectively. The condition is caused by the chronic exposure of acid produced by oral bacteria that leads to the destruction of the dental hard tissues, causing pain, infection, and even tooth loss.
In this project, new cutting-edge synchrotron X-ray tomography techniques to further the understanding of caries and how acid damages teeth have been developed. Including the first, time-resolved study of dentine demineralisation using high-speed synchrotron X-ray tomography which was able to quantify the microstructural changes in the dentine tubules and measure the rate of demineralisation. A novel method for reconstructing crystalline properties, such as crystallite size and strain, measured using synchrotron X-ray diffraction tomography was also established. This method was later used to compare the structural changes in natural carious and artificially demineralised dentine. The findings showed that for artificial demineralisation to resemble the natural process, a process of pH cycling must be applied.
Furthermore, when the natural dentition is no longer capable of continuing their function, dental crowns are used as replacements. With conditions like caries becoming more prevalent at younger ages, the need for longer lasting dental crowns is growing.
This project studied the mechanical properties of bioinspired ceramic-polymer composites, as part of the development of next generation dental crown restorations. In particular, this project investigated the integration of a nanoindenter on a synchrotron beamline, as part of a proof-of-concept study, to enable in situ X-ray diffraction tomography mechanical testing of the proposed composite materials, to measure strain evolution. The initial results have highlighted some challenges, such as dominant single crystal diffraction spots, that will need to be appropriately handled during experimental planning and data processing.