Gene expression of potential tooth eruption molecules in the dental follicle of the mouse

Abstract

Tooth eruption requires alveolar bone resorption and the presence of the dental follicle, a loose connective tissue sac that surrounds each tooth. This bone resorption involves the follicle in that mononuclear cells enter the follicle to form osteoclasts which resorb bone to form the eruption pathway. In the rat first mandibular molar, probable eruption genes, CSF-1, c-fos, NFkappaB and MCP-1, are expressed maximally in the dental follicle at day 3 postnatally. This correlates with the time of peak influx of mononuclear cells into the follicle. In the mouse, the first peak influx of mononuclear cells into the first mandibular molar is at day 5 postnatally, and this study demonstrates that all four of the above resorption molecules are maximally expressed at this time in the dental follicle. Thus, this work suggests that these molecules may play a role in the cellular events of eruption (mononuclear cell influx and osteoclast formation) in the mouse molar at day 5 postnatally just as they do at day 3 in the rat molar. These results provide a standard for future studies on eruption in the mouse molar and extends the number of species in which putative eruption molecules are expressed at a critical time of eruption.

Cementum: A Phosphate-sensitive Tissue

“…Recognition that periodontal regeneration is possible has resulted in investigators' increased attempts to understand the cellular and molecular mechanisms and the factors that regulate formation of these tissues during development, maintenance, and regeneration. Clues to understanding the roles of specific factors in the regenerative process have come from developmental studies that examined the expression of genes/proteins during development of the periodontium (Wise et al, 1995(Wise et al, , 1999Takahashi and Ikeda, 1996;Aberg et al, 1997;D'Errico et al, 1997;Wise, 1998). We now show that inorganic pyrophosphate (PP i ) is one of the crucial factors that regulate both the initiation and maturation of cementum.…”

Reduction of Osteoclasts in a Critical Embryonic Period Is Essential for Inhibition of Mouse Tooth Eruption

“…Because resorption of alveolar bones is essential, previous studies about tooth eruption have focused on the tooth crown regions (2,30,31,43) . The expression of M‐CSF and c‐Fms, or other cytokines that may attract monocytes (precursors of osteoclasts) in the dental follicle, which is a loose connective tissue surrounding the developing tooth, has also been studied (44–46) . On the other hand, we emphasize that the inhibition of tooth eruption analyzed here is a part of the osteopetrotic condition and suggest that the number of TRAP + cells is a useful parameter.…”

Cellular and molecular basis of tooth eruption

“…Targeted RT-PCR studies showed that colony-stimulating factor-one (CSF-1) and monocyte chemotactic protein-1 (MCP-1) were maximally expressed in the DF at day 3, the time of maximal influx of mononuclear cells (12,13). This correlation is strengthened by studies in mice in which the maximal influx of mononuclear cells is at day 5 (14) and the maximal expression of CSF-1 and MCP-1 is at day 5 in the mouse DF (15). In vitro, both MCP-1 and CSF-1 are secreted by the DF cells and are chemotactic for monocytes (13).…”