[beta]-catenin immunoreactivity in the dental lamina
, the dental mesenchyme and the enamel knot.
hyperactivity theory, the most accepted one, suggests the localized and independent hyperactivity of the dental lamina
to be the cause for the development of ST [7, 35].
During the thickening of the prospective tooth region epithelium which then forms the dental lamina
, the expressions of Fgf10 and Fgf18 are found in the mesenchyme [63, 65].
It is a benign, uni or multicystic intraosseous tumor, which originates from the dental lamina
and its remnants, with a characteristic lining of Parakeratinized layered squamous epithelium.
Another hypothesis favors the origin of the tumor cells from the cells of the dental lamina
found in the initial stage of odontogenesis and the remnants of the dental lamina
The aetiology behind agenesis of one or more molars is unknown, but several mechanisms have been suggested like a physical disruption of dental lamina
in the developmental stage, limitation of space, an inherent defect of dental lamina
and failure of induction of the underlying mesenchyme.
This lesion turned out to be an odontogenic keratocyst arising from the cell rests of the dental lamina
. These are commonly found in the 3rd molar region of the mandible.] They can be large and destructive and may present with pain or other symptoms.
The phylogenetic theory as a regression to the anthropoids whose dentition had more teeth, the autonomic recessive inheritance or linkage to the x chromosome, an abnormal reaction to a local traumatic episode, environ mental factors, dichotomy of the tooth germ, and the theory of hyperactivity of the dental lamina
are the most accepted ones .
These variants have common histologic characteristics that indicate a common origin as derived from the complex system of dental lamina
or its remnant .
Morphologically, the dental lamina
exhibits cubic cells arranged in islands (Figure 2B).
Whereas most vertebrates can replace teeth throughout their lives, human teeth are naturally replaced only once, despite the lingering presence of a band of epithelial tissue called the dental lamina
, which is crucial to tooth development.
USC researchers identified three developmental phases for each alligator tooth unit, comprising a functional tooth (f), replacement tooth (r) and dental lamina
One theory suggests that the supernumerary tooth is created as a result of a dichotomy of the tooth bud.7,8 Another theory, well supported in the literature, is the hyperactivity theory, which suggests that supernumeraries are formed as a result of local, independent, conditioned hyperactivity of the dental lamina
.8 Heredity may also play a role in the occurrence of this anomaly, as supernumeraries are more common in the relatives of affected children than in the general population.7 However, the anomaly does not follow a simple Mendelian pattern.7 A mesiodens should be suspected when there is asymmetry in the eruption pattern of the maxillary incisors.1 Early diagnosis of a mesiodens minimizes the treatment required and prevents development of associated problems.
An odontogenic cyst is formed by activation of odontogenic cell rests entrapped within the bone tissue or gingival tissue of the jaws, such as the epithelial remains of Malassez, the dental lamina
(cell rests of Serres), or the enamel organ.