Second permanent molars: embryological origin, development and eruption. Role of the RANK/RANKL/OPG pathway

¹ Dentofacial Orthopedics Department, Pitié-Salpêtrière Hospital, Paris, France
² Molecular oral pathophysiology laboratory, INSERM UMR 1138, Paris, France
³ Faculty of Odontologie, Antioquia University, Colombia
⁴ INSERM UMR 957, University of Nantes, France

Address for correspondence: Beatriz Castaneda – Facultad de Odontologia, Universidad de Antioquia – Colombia Laboratoire de Physiopathologie Orale Moléculaire, INSERM 1138 15 Rue de l’École de Médecine, 75270 Paris 06, France. E-mail: bea.castaneda.1@gmail.com

Received: 3 May 2015
Accepted: 30 May 2015

Abstract

Craniofacial skeleton formation, and more specifically alveolar bone development, follow a finely regulated controlled genetic program. A spatial and temporal combination of molecular signals determines the type and inter- and intra-maxillary position of each dental-alveolar unit. The volumetric growth and movement of tooth germs depend on a coordinated adaptive peripheral alveolar bone modeling process which is supported by signaling pathways between cells of the dental epithelium, dental follicle and alveolar bone. These signaling pathways involve transcription factors, proto-oncogenes and diffusible factors called “growth factors”. Transient impairment of these signals during time windows corresponding to the development of the various dental types could explain specific localized eruption deficits in a given dental type, as observed for second molars. Ongoing studies show that disturbances of bone resorption related to disruption of the RANKL/RANK/OPG signaling pathway affect tooth eruption and root morphogenesis, with a clear relationship between the time window of onset of disruption and the affected dental type.