Biomechanical function of the periodontal ligament in biting and orthodontic tooth movement

McCormack, Steven William

March 2016

Thesis or dissertation

© 2016 Steven William McCormack. All rights reserved. No part of this publication may be reproduced without the written permission of the copyright holder.

Alveolar bone remodelling is vital for the success of dental implants and orthodontic treatments. However, the underlying biomechanical mechanisms, in particular the function of the periodontal ligament (PDL) in bone remodelling, are not well understood. The PDL is a soft fibrous connective tissue that joins the tooth root to the alveolar bone and plays a critical role in the transmission of loads from the teeth to the surrounding bone. However, due to its complex structure, small size and location within the tooth socket it is difficult to study in vivo. Finite element analysis (FEA) is an ideal tool with which to investigate the role of the PDL, but inclusion of the PDL in FE models is complex and time consuming and most FE models that include teeth do not consider the PDL. The aim of this study was to investigate the effects of including the PDL and its fibrous structure in mandibular finite element models.

This research involved the development of a novel method to include the fibres of the PDL in FE models. A simplified single tooth model was developed to assess the effects of modelling fibrous PDL compared to the traditional approach of representing the PDL as a simple layer of solid material and to an absent PDL. The same study design was then applied to a high-resolution model of the human molar region, which is the first time that the fibrous structure of the PDL has been included in a model with realistic tooth and bone geometry. Finally, molar region models of five additional species (cat, cercocebus, pig, rabbit and sheep) were tested with and without a PDL.

The results from the research showed that omission of the PDL creates a more rigid model, reducing the strains observed in the mandibular corpus for all six species studied. This suggests that the results obtained are not specific to the human molar region, but may be true for the mammalian mandible in general. Compared to a solid PDL, the fibrous PDL altered the strains in the models, in particular increasing the strains observed in the tooth socket. This may be important for the management of orthodontic treatment, as strains in this region are thought to play an important role in bone remodelling during orthodontic tooth movement.

School of Engineering, The University of Hull
Fagan, M. J. (Michael J.), 1957-; Gröning, Flora
Sponsor (Organisation)
Biotechnology and Biological Sciences Research Council (Great Britain); Seventh Framework Programme (European Commission); University of Hull
Grant number
BB/I008462/1 (Biotechnology and Biological Sciences Research Council); FP7-PEOPLE PERG7-GA- 2010-268430 (Marie Curie Actions Integration Grant)
Qualification level
Qualification name
7 MB
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