Ankylosis of Primary Molars – Seeking an Answer

Recent Research Review

“Epigenetic Marks Define the Lineage and Differentiation Potential of Two Distinct Neural Crest-Derived Intermediate Odontogenic Progenitor Populations" (Gopinathan G et al)

       The etiology of primary molar ankylosis has eluded the profession for many decades. While the elusive nature of this pathology has continued to plague the Pediatric Dentist and others, some remarkable research has appeared recently that opens new avenues for discussion.

        This review is based on the bibliographic reference given below as well as some related papers from the same laboratory.

        This research team is headed by Dr. Thomas Diekwisch et al who until recently was the first director of the Brodie laboratory for Craniofacial Genetics and the Allan G. Brodie Endowed Chair. His research at the University of Illinois focuses on stem cells and epigenetic control of pluripotency by the chromatin remodeling factor CP27. Dr. Diekwisch is currently on the faculty of Baylor College of Dentistry at Baylor, Texas.

        This laboratory uses tissue culture technology to redefine the roles played by dental pulp (DP) and dental follicle (DF) progenitors cells that are ultimately responsible for other dental tissues.

        In his abstract we quote, “Epigenetic mechanisms, such as histone modifications, play an active role in the differentiation and lineage commitment of mesenchymal stem cells. In the present study, epigenetic states and differentiation profiles of two odontogenic neural crest-derived intermediate progenitor populations were compared: dental pulp (DP) and dental follicle (DF).”

        Later in the abstract he continues, “the present study indicates that the DF intermediate odontogenic neural crest lineage is distinguished from its DP counterpart by epigenetic repression DSPP and DMP 1 genes and through dynamic histone enrichment responses to mineralization induction. Findings presented here highlight the crucial role of epigenetic regulatory mechanisms in the terminal differentiation of odontogenic neural crest lineages.”

        Another quote completes the theme of which progenitor cells are involved in tooth formation.  “dental papilla progenitors differentiate into dental pulp (DP) and odontoblasts, which in turn secrete tooth dentin, while (DF) progenitors migrate extensively and eventually form periodontal ligament (PDL), alveolar bone (AB), and root cementum (CEM). The terminal differentiation of these intermediate progenitors into DP odontoblasts, tooth dentin, and cells and tissues of the periodontal apparatus is controlled by both genetic and epigenetic factors.

        Mesenchymal cells are the progenitors of dental tissues. As the title suggests, the final form of dental tissues is the result of epigenetic marks.

        These mechanisms are the result of histone modifications that play a role in the differentiation and lineage commitment of mesenchymal stem cells. This translational research appears to have unusual merit since it aligns current thinking about the etiology with solid research protocols. Dr. Diekwisch and his colleagues sought to distinguish the roles that are played by DP cells and the cells of the DF cells in culture.



        1. Gopinathan G, Kolokythas A, Luan X, Diekwisch TGH. Epigenetic marks define the lineage and differentiation potential of two distinct neural crest-derived intermediate odontogenic progenitor populations. Stem Cells Dev. 2013;22(12):1763–78. doi:10.1089/scd.2012.0711.

         2. Kangaria SJ, Y Ito, X Luan and TG Diekwisch. (2011). Differentiation of neural-crest-derived intermediate pluripotent progenitors into committed periodontal population involves unique molecular signature changes, cohort shifts, and epigenetic modifications. Stem Cells Dev 20:39-52.