[beta]-catenin is present during all stages of odontogenesis (Liu et al.; Lo Muzio et al.), in both enamel epithelium
and dental mesenchyme.
LaCL: labial cervical loop; LiCL, lingual cervical loop; TA cells: transit-amplifying cells; OEE: outer enamel epithelium
; SR: stellate reticulum.
Kaneko, "Primary intraosseous carcinoma of the mandible with probable origin from reduced enamel epithelium
," Journal of Oral Pathology and Medicine, vol.
Expression of protein kinases C betai, betall, and VEGF during the differentiation of enamel epithelium
in tooth development.
They originate from the epithelium involved with the formation of teeth: enamel, odontogenic rests of Malassez, reduced enamel epithelium
, and odontogenic cyst lining; and are locally invasive with infiltrative growths and frequent recurrences even after radical surgical treatment.
It has been reported that in unerupted teeth the resorptive process commences adjacent to the defective enamel epithelium
[Blackwood, 1958], and progresses in an irregular manner from an isolated area within the enamel and subsequently continues to progress towards the dentine.
In the developing tooth, VEGF and VEGFR-2 are expressed in odontoblasts and the inner enamel epithelium
may regulate odontoblast development and the differentiation of inner enamel epithelium
to ameloblasts (Aida et al., 2005; Miwa et al., 2008) VEGF expression in pulp fibroblasts and odontoblasts of human teeth is higher in immature than mature permanent teeth, suggesting a role of VEGF in tooth maturation (Wang et al., 2007).
However strongest contention is that the cyst originates from reduced enamel epithelium
as epithelial lining is attached to the neck of tooth.
The inner and outer enamel epithelium
proliferate from the cervical loop of the enamel organ and make a doubled layer of cells named Hertwig's epithelial sheath.
In both patterns, the outermost cells resemble those of the ameloblastic layer and the inner enamel epithelium
. Histologic variations within the epithelial islands give rise to histologic subclasses (e.g., cystic, acanthomatous, granular cell, basal cell, and hemangiomatous).
Discussion: There is a lack of consensus on the aetiology of dens invaginatus the cause of DI is still unknown and controversial, possible mechanisms of this phenomenon may be listed as:(1) abnormal pressure from the surrounding tissues, (2) rapid and aggressive proliferation of a part of the internal enamel epithelium
invading the dental papilla, (3) local growth retardation, (4) invagination of the crown before calcification of the teeth, (4) infection and (5) genetic factors.
Palato gingival grooves, also called palatoradicular grooves or radicular lingual grooves are developmental anomalies in which an infolding of the inner enamel epithelium
and Hertwig's epithelial root sheath create a groove that passes from the cingulam and extend varying distances apically on to the root.