Cellular, Molecular, and Genetic Determinants of Tooth Eruption

Abstract

Tooth eruption is a complex and tightly regulated process that involves cells of the tooth organ and the surrounding alveolus. Mononuclear cells (osteoclast precursors) must be recruited into the dental follicle prior to the onset of eruption. These cells, in turn, fuse to form osteoclasts that resorb alveolar bone, forming an eruption pathway for the tooth to exit its bony crypt. Some of the molecules possibly involved in the signaling cascades of eruption have been proposed in studies from null mice, osteopetrotic rodents, injections of putative eruption molecules, and cultured dental follicle cells. In particular, recruitment of the mononuclear cells to the follicle may require colony-stimulating factor-one (CSF-1) and/or monocyte chemotactic protein-1 (MCP-1). Osteoclastogenesis is needed for the bone resorption and may involve inhibition of osteoprotegerin transcription and synthesis in the follicle, as well as enhancement of receptor activator of NF B ligand (RANKL), in the adjacent alveolar bone and/or in the follicle. Paracrine signaling by parathyroid-hormone-related protein and interleukin -1␣, produced in the stellate reticulum adjacent to the follicle, may also play a role in regulating eruption. Osteoblasts might also influence the process of eruption, the most important physiologic role likely being at the eruptive site, in the formation of osteoclasts through signaling via the RANKL/OPG pathway. Evidence thus far supports a role for an osteoblast-specific transcription factor, Cbfa1 (Runx2), in molecular events that regulate tooth eruption. Cbfa1 is also expressed at high levels by the dental follicle cells. This review concludes with a discussion of the several human conditions that result in a failure of or delay in tooth eruption.

Oral Tissues as Source for Bone Regeneration in Dental Implantology

“…The dental follicle develops from ectomesenchyme. It surrounds the developing tooth germ before eruption (Ten Cate, 1997;Wise, 2002). During embryonic development, the ectomesenchyme is partly derived from migrating cells of the cranial neural crest.…”

Immunoassay analysis of proteins in gingival crevicular fluid samples from resorbing teeth

“…The dental follicle that lies above the erupting permanent tooth plays a key role in tooth transposition through the mineralized tissue crypt since the follicular cells secrete important chemicals to replenish osteoclasts and odontoclasts in the area. 12,13 In this cascade of molecular signals that regulates tooth eruption within the follicle, Que et al 14,15 demonstrated that the IL-1 family plays a major role. The IL-1 family is comprised of 3 ligands, IL-1a, IL-1b, and IL-1RA, all of which bind the IL-1 receptor.…”

What is the Role of Pediatricians on Oral Health?

“…Primary teeth will shed (exfoliate) to their permanent successors. Although many theories have been advanced (Marks Jr., 1996;Philbrick et al, 1998;Wise et al, 2002), the factors responsible for the eruption of the teeth are not fully understood. The factors that have been related to the eruption of teeth include elongation of the root, forces exerted by the vascular tissues around and beneath the root, growth of the alveolar bone, growth of dentin, growth and pull of the periodontal membrane, hormonal influences (pituitary growth hormone, thyroid hormone, and parathyroid hormone-related protein), presence of a viable dental follicle, pressure from the muscular action, and resorption of the alveolar crest.…”

“…The factors that have been related to the eruption of teeth include elongation of the root, forces exerted by the vascular tissues around and beneath the root, growth of the alveolar bone, growth of dentin, growth and pull of the periodontal membrane, hormonal influences (pituitary growth hormone, thyroid hormone, and parathyroid hormone-related protein), presence of a viable dental follicle, pressure from the muscular action, and resorption of the alveolar crest. A review article by Wise et al (Wise et al, 2002) focused on the molecular signals that initiate tooth eruption. They stated that tooth eruption is a complex and tightly regulated process involving cells of the tooth organ and surrounding alveolus.…”