Project Details
Projekt
Structure and damage resistance on the nano- and microscale of the cemento-dentine-junction
Subject Area
Biomaterials
Term
since 2021
Project identifier
Deutsche Forschungsgemeinschaft (DFG) - Project number 396127899
Mammal teeth are suspended in the jaw via the periodontal ligament and the cementum which covers the root dentine. Dentine and cementum, bony tissues of similar stiffness, are connected by a thin, more compliant interzone, the cemento-dentine junction (CDJ). Over the human lifespan, the CDJ endures millions of cyclic chewing stresses, with no clinically reported cases of failure, even though it has no capacity for repair. Maybe this clinical inconspicuousness is the reason why the CDJ has only sparsely been investigated, so far. The CDJ is further less porous than the surrounding tissues. Therefore, it has been assumed to act as a permeability barrier for cells, bacterial acids, bacterial by-products, and the bacteria themselves. It might therefore play a role in pathological processes like root resorption, root caries and endodontic infections. Within the scope of FOR2804, we aim to better understand the relationship between microstructure and functional properties of this endurable interzone. We want to elucidate the design principles leading to its fatigue resistance, and we will focus on permeability aspects and its role in pathological processes. In particular, we will analyse the role of the CDJ in the root caries and diffusion processes using chemical and bacterial caries models. Further, we wish to understand whether the regionally different loading conditions are reflected in micro- and nano-structural local variations of the CDJ and whether temporal load changes lead to adaptive changes in CDJ structure and characteristics. We plan i) to characterise the micro- and nanostructure as well as the micro- and nano-mechanical properties of the CDJ, and the influence of species, tooth type, and location along the root surface; ii) to focus on the organic components, and possible changes to the residual strain state in the mineral phase following root caries processes, and we will evaluate the impact of bacterial acids on the quasistatic and fatigue properties of the CDJ, by testing specimens extracted from the CDJ in regions adjacent to caries or diffusion-affected areas, and under consideration of the altered loading state along the root due to the cariotic lesions, assessed by finite element modelling; iii) to investigate the micro- and nano-fatigue properties of the CDJ about locally varying in vivo loading conditions along the root surface; iv) for comparison with dental interzones, where residual stresses and interlocking are present, to test such interzones in fatigue, in collaboration with the other InterDent2 projects. Thus, we will gain a better understanding of the structure/property relationship and the function of the CDJ, which will allow us to derive general material science principles that constitute a durable and fatigue-resistant interzone between two stiffer materials.
DFG Programme
Research Units
