As mentioned earlier, the supporting alveolar bone is derived from condensed mesenchymal cells around the developing epithelial tooth germ
, and it subsequently forms sockets for the teeth at the bell stage.
Gene expression profiling of ameloblastoma and human tooth germ
by means of a cDNA microarray.
Before mineralization, severe damage such as mechanical trauma to the tooth germ
as well as multiagent chemotherapy and radiation therapy may arrest the development, leading to absence of a tooth.
It is relatively more common in maxilla because of its susceptibility to traumatic injury and the close proximity of the developing tooth germ
to primary teeth7.
Triple immunofluorescent labeling of human tooth germ
in 1973 and 1976 defined four developmental crowns and four developmental root stages which were based on radiological tooth germs
. They used Figure A-H instead of numbers to present the impression of an equal duration of each stage [Figure 4].
Malformed teeth and unerupted teeth in the jaw were due to compression and alteration of tooth germ
due to excess formation of bone during the development of tooth.
Besides causing pain, traumatic injuries of primary teeth can affect normal function, aesthetics [Rajab, 2003] and the developing tooth germ
[Diab and elBadrawy, 2000].
The calcified portion of the permanent tooth germ
is displaced in such a way that the remainder of the permanent tooth germ
forms at an angle to it.
Radiographic examination showed no permanent tooth germ
under the primary second molar, no periradicular lesion, and uniform bone between the primary second molar tooth and the first permanent premolar (Figures 1(b) and 1(c)).
It may arise from the accumulation of fluid between the enamel epithelium and the crown of the permanent tooth germ
or from remnants of the odontogenic epithelium.
At 16 day intrauterine life, morphogenesis proceeds as the epithelial cells proliferate and form the enamel organ surrounding the mesenchymal dental papilla and the tooth germ
in the cap stage.