Molecular Characterization of Human Impacted Third Molars: Diversification of Compartments

Abstract

To gain more insight into the development of human teeth, we characterized different compartments of impacted third molars at two developmental stages by assessing expression levels of a set of genes. We considered genes known to be essential for the development of teeth and ectomesenchyme as well as genes covering characteristic features of stemness. Molars were divided into the operculum, periodontal ligament, developing pulp and, using a new approach, the pad-like tissue beneath the developing pulp. Markers for ectomesenchyme and tooth development known from rodents were assayed by semiquantitative PCR and every compartment was assigned its own signature of gene expression. The expression of markers characteristic of stem cells pointed to multipotent features. The expression patterns found shift in the course of development underscoring the relevance of these genes involved in human tooth development. The results suggest an inherent asymmetry between the developing pulp and pad-like tissue established early in tooth development. A microarray analysis of cells derived from pad-like tissue and pulp proper was performed to obtain cues regarding the consequences of tissue diversification. Both sets of data support the validity of our new approach to the subdivision of the developing tooth, by indicating a compartment-dependent commitment of isolated cells probably due to the postulated asymmetry within the developing tooth germ.

Using human neural crest-derived progenitor cells to investigate osteogenesis: An in vitro study

“…The starting point for this study were our recent reports that identified dental neural crest-derived progenitor cells (dNC-PCs) as good candidates to regenerate neural crest-derived tissues within the craniofacial region (Degistirici et al, 2008;Schoenebeck et al, 2009). As dNC-PCs could be easily differentiated into osteogenic lineages we speculated whether these cells may be useful to engineer facial and jaw skeleton.…”

“…Surgically removed impacted third molars of young adults were used to prepare dental neural crest-derived progenitor cells (dNCPCs) (Degistirici et al, 2008;Schoenebeck et al, 2009). Written consent was obtained from all parents of the participating patients.…”

“…When subcultured as monolayers in standard growth medium, dNC-PCs showed the distinct phenotype of multipotent progenitor cells as described previously (Degistirici et al, 2008;Schoenebeck et al, 2009). To induce cells of osteogenic lineage for experimentation, dNC-PCs were initially preincubated for 4-7 days with growth medium in the presence of 10% FCS.…”

“…The developing field of craniofacial tissue engineering promises the regeneration of dental, oral, and craniofacial structures (Mao et al, 2006). Recent evidence suggests that the connective tissue of the human tooth contains a particular population of neural crest-derived progenitor cells (termed dNC-PCs) which give rise to a wide range of specialized daughter cells when outside their dental signal network (Degistirici et al, 2008;Schoenebeck et al, 2009). In attempting to use dNC-PCs for tissue engineering we showed that it was possible to induce bone formation in a nude mouse model by combining dNC-PCs with bovine bonederived granulates, which act as a scaffolding component.…”

Desenvolvimento de metodologia radiográfica e volumétrica dos diferentes estágios de desenvolvimento dentário para qualificação de material biológico em Engenharia Tecidual

“…Os resultados indicaram o modelo de construct viável para o substituto biológico dentário, demonstrando o surgimento de estruturas organizadas tais como: esmalte, dentina, polpa, periodonto; e ligamento periodontal. Schoenebeck et al (2009) Nicodemo (1967) utilizou uma amostra de pacientes brasileiros oriundos do…”