Current perspectives on tooth implantation, attachment, and replacement in Amniota
- 1UMR5242 Institut de Génomique Fonctionnelle de Lyon (IGFL), France
- 2Service d'Odontologie, Hospices Civils de Lyon, France
- 3Faculté d'Odontologie, Claude Bernard University Lyon 1, France
- 4Departement of Biological Sciences, University of Alberta, Canada
Teeth and dentitions contain many morphological characters which give them a particularly important weight in comparative anatomy, systematics, physiology and ecology. As teeth are organs that contain the hardest mineralized tissues of vertebrates, their fossil remains are abundant and the study of their anatomy in fossil specimens is of major importance in evolutionary biology. Comparative anatomy has long favored studies of dental characters rather than features associated with tooth attachment and implantation. Here we review a large part of the historical and modern work on the attachment, implantation and replacement of teeth in Amniota. We propose synthetic definitions or redefinitions of most commonly used terms, some of which have led to confusion and conflation of terminology. In particular, there has long been much conflation between dental implantation that strictly concerns the geometrical aspects of the tooth-bone interface, and the nature of the dental attachment, which mostly concerns the histological features occurring at this interface. A second aim of this work was to evaluate the diversity of tooth attachment, implantation and replacement in extant and extinct amniotes in order to derive hypothetical evolutionary trends in these different dental traits over time. Continuous dental replacement prevails within amniotes, replacement being drastically modified only in Mammalia and when dental implantation is acrodont. By comparison, dental implantation frequently and rapidly changes at various taxonomic scales and is often homoplastic. This contrasts with the conservatism in the identity of the tooth attachment tissues (cementum, periodontal ligament, alveolar bone), which were already present in the earliest known amniotes. Because the study of dental attachment requires invasive histological investigations, this trait is least documented and therefore its evolution currently poorly understood. Finally, it is essential to go on collecting data from all groups of amniotes in order to better understand and consequently better define dental characters.
Keywords: Tooth implantation, Tooth replacement, Periodontium, Amniota, evolution, thecodonty, pleurodonty, Acrodonty
Received: 24 Sep 2018;
Accepted: 29 Oct 2018.
Edited by:Pierfrancesco Pagella, University of Zurich, Switzerland
Reviewed by:Zerina Johanson, Natural History Museum, United Kingdom
Igor Adameyko, Karolinska Institutet (KI), Sweden
Copyright: © 2018 Bertin, Thivichon-Prince, LeBlanc, Caldwell and Viriot. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) and the copyright owner(s) are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.
* Correspondence: Prof. Laurent Viriot, UMR5242 Institut de Génomique Fonctionnelle de Lyon (IGFL), Lyon, 69007, Rhône-Alpes, France, email@example.com