The Cell Biology of Amelogenesis
Colin Robinson, Jennifer Kirkham, Roger Shore in Dental Enamel, 2017
With continued morphogenetic movements, a structure is formed with close resemblance to the shape of the future crown (the bell stage). A basal lamina separates the IEE from the dental papilla, and denotes the shape and position of the future dentine-enamel junction. Through a series of epithelial-mesenchymal interactions,5-8 cells of the IEE eventually become cytodifferentiated enamel-matrix secreting ameloblasts (for a more detailed discussion of these interactions, see Chapter 1). Cells of the dental papilla will become the odontoblasts and pulp of the future tooth. Tissue recombination experiments have shown that the dental papilla is responsible for controlling the shape of the developing tooth.9,10 The dental follicle cells (outside the OEE) eventually will take part in the formation of cementum, periodontal ligament, and alveolar bone.11
Bone, Muscle, and Tooth
Pritam S. Sahota, James A. Popp, Jerry F. Hardisty, Chirukandath Gopinath, Page R. Bouchard in Toxicologic Pathology, 2018
Dysplastic lesions can vary considerably, depending on the nature and extent of injury, the tissues affected, and the plane of section. Alveolar bone, cementum, dentin, enamel, and/or connective tissue resembling that of the dental papilla may develop in various combinations and abnormal patterns. In some cases, the tooth socket becomes filled with large irregular masses of osteodentin surrounded by fragments of the original tooth. Tooth-like structures (denticles), with tissue resembling the dental papilla, may also form but tend to remain relatively small and solitary. Dental dysplasia needs to be carefully considered as an alternative diagnosis to a dental neoplasm (odontoma). Dental dysplasia (abnormal development) may give rise to fractures, which are sometimes difficult to see microscopically due to histological processing/sectioning in areas of the tooth not containing the fracture. Dysplasia and fractures may also lead to ankylosis, which is fusion of alveolar bone with the tooth.
Mouth and throat, face, and the five senses
Frank J. Dye in Human Life Before Birth, 2019
In Chapter 12 the concept of epithelial–mesenchymal interactions was introduced in the context of skin development. Here, we consider an additional example of such interactions in the development of the tooth. The tooth arises from an interaction between oral epithelium and mesenchyme, with the epithelial component becoming the enamel organ and the mesenchyme becoming the dental papilla. The enamel organ contains ameloblasts, cells that give rise to the enamel of the developing tooth, while the dental papilla contains odontoblasts, cells derived from migratory neural crest cells, which give rise to the dentin of the developing tooth.
Expression Levels of WNT Signaling Pathway Genes During Early Tooth Development
Published in Organogenesis, 2023
Yuhan Song, Fujie Song, Xuan Xiao, Zhifeng Song, Shangfeng Liu
Dickkopf-related protein 1(Dkk1) is a typical antagonist of Wnt/β-catenin signaling by competing for the Wnt receptor LRP5/6. The mutation of Dkk1 may cause oligodontia and short root anomaly.27,66 Researchers observed that strong expression of Dkk1 was localized in preodontoblasts on the labial side of the incisors.67 At postnatal day 2, Dkk1 is prominently expressed in the preodontoblasts and odontoblasts in mouse molar germs.68 In Dkk1 transgenic mice, overexpression of Dkk1 in pulp and odontoblast cells delayed the maturation of dentinogenesis during post-natal development.69 The dental crown begins to form in the late bell stage (P1). In this stage, peripheral cells of the dental papilla differentiate into odontoblasts that secrete dentin. Our results demonstrated that Dkk1 was significantly expressed in the P1 phase, which indicated that Dkk1 played an important role in the formation of dentin.
Dental stem cells in tooth regeneration and repair in the future
Published in Expert Opinion on Biological Therapy, 2018
Christian Morsczeck, Torsten E. Reichert
Somatic dental stem cells are also located in other tissues of the tooth, all of which come from the dental mesoderm [20]. Two dental mesodermal tissues can be obtained from postnatal teeth: the dental pulp and the PDL. While the enamel organ is almost lost before tooth eruption, two mesodermal tooth germ tissues, the apical dental papilla and the dental follicle, can be obtained from impacted third molar teeth [7,8]. Interestingly, these tooth germ tissues are probably the only available embryonic-like tissues in healthy human adults. They are also the progenitors either for the dental pulp (apical dental papilla) or for the PDL (dental follicle). Stem cells of the apical dental papilla and of the dental follicle are related to stem cells of the dental pulp and to stem cells of the PDL, respectively. This article focuses mainly on dental mesodermal stem cells and describes their opportunities for cell therapies in the future. Furthermore, we are speculating about the necessary basic research, which must be carried out before dental stem cells can be used successfully in the clinic. Finally this article briefly discusses the potential of dental stem cells for immunotherapies and those of induced pluripotent stem cells (iPSCs) for whole tooth regeneration.
Dental stem cells for tooth regeneration: how far have we come and where next?
Published in Expert Opinion on Biological Therapy, 2023
The result of the latter study seems to contradict the use of xenogeneic materials, but such side effects can also be useful for successful cell therapy. For example, new insights have been gained from basic research on apoptotic death after stem cell implantation in an ischemic-hypoxic environment. Li et al. explored the role played by the extracellular vesicles (EVs) derived from apoptotic cells [54]. They used apoptotic vesicles from SHED and showed that these vesicles were taken up by endothelial cells and elevated the expression of angiogenesis-related genes, resulting in pulp revascularization [54]. These results point to the importance of apoptosis in tissue regeneration, which has previously also been discussed for osteogenic differentiation of mesenchymal stem cells [55]. Moreover, another study is also an excellent example of EVs for dental stem cell-based regenerative therapies. Guo et al. showed that exosomes, which are membrane bound EVs, strengthened bone regeneration of DPSCs through the activation of mitochondrial aerobic metabolism. They showed that exosomes were rich in mRNA for mitochondrial transcription factor A, which shuttled to promote osteogenic differentiation by activating mitochondrial aerobic metabolism [56]. A possible alternative to the manipulation of the mitochondrial metabolic state by EVs could be thermoplasmonic regulation with a laser-based treatment, which could significantly improve the differentiation of DPSCs [57]. Interestingly, another study exploited the idea that the formation of dentin-pulp involves complex epithelial–mesenchymal interactions between Hertwig’s epithelial root sheath cells (HERS) and dental papilla cells (DPCs) [58]. They showed that EVs derived from Hertwig’s epithelial root sheath cells were also able to promote the regeneration of dentin-pulp tissue in an in vivo tooth root slice model.
Related Knowledge Centers
- Dentin
- Ectomesenchyme
- Enamel Organ
- Histology
- Odontoblast
- Embryology
- Uterus
- Prenatal Development
- Cell
- Animal Tooth Development