Early Regression of the Dental Lamina Underlies the Development of Diphyodont Dentitions

0379143 - ÚŽFG 2013 RIV US eng J - Journal Article
Buchtová, Marcela - Štembírek, J. - Glocová, K. - Matalová, Eva - Tucker, A.S.
Early Regression of the Dental Lamina Underlies the Development of Diphyodont Dentitions.
Journal of Dental Research. Roč. 91, č. 5 (2012), s. 491-498. ISSN 0022-0345. E-ISSN 1544-0591
R&D Projects: GA AV ČR KJB601110910
Institutional research plan: CEZ:AV0Z50450515
Keywords : developmental biology * dental morphology * tooth development
Subject RIV: EB - Genetics ; Molecular Biology
Impact factor: 3.826, year: 2012

Functional tooth germs in mammals, reptiles, and chondrichthyans are initiated from a dental lamina. The longevity of the lamina plays a role in governing the number of tooth generations. Monophyodont species have no replacement dental lamina, while polyphyodont species have a permanent continuous lamina. In diphyodont species, the dental lamina fragments and regresses after initiation of the second tooth generation. Regression of the lamina seems to be an important mechanism in preventing the further development of replacement teeth. Defects in the complete removal of the lamina lead to cyst formation and has been linked to ameloblastomas. Here, we show the previously unknown mechanisms behind the disappearance of the dental lamina, involving a combination of cell migration, cell-fate transformation, and apoptosis. Lamina regression starts with the loss of the basement membrane, allowing the epithelial cells to break away from the lamina and migrate into the surrounding mesenchyme. Cells deactivate epithelial markers (E-cadherin, cytokeratin), up-regulate Slug and MMP2, and activate mesenchymal markers (vimentin), while residual lamina cells are removed by apoptosis. The uncovering of the processes behind lamina degradation allows us to clarify the evolution of diphyodonty, and provides a mechanism for future manipulation of the number of tooth generations.
Permanent Link: http://hdl.handle.net/11104/0210407