Tooth enamel is the most highly mineralized tissue in the body and it is a unique tissue that differs from other types of hard tissue since tooth enamel is formed by ameloblasts
that are derived from the dental epithelium.
Induction of human keratinocytes into enamel-secreting ameloblasts
. Dev Biol.
differentiation occurs and subsequently forms ectopic enamel on the lingual side of the incisor in [Spry2.sup.+/-]; [Spry4.sup.-/-] mice [93, 94].
In the presecretory ameloblast
and odontoblast, staining was mainly cytosolic and nuclear, although a few vesicles were also stained (Bourd-Boittin et al.).
Environmental conditions thought to affect ameloblast
function range from ill-health during pregnancy to perinatal medical conditions such as premature birth and low birth weight to early childhood acute illnesses including pneumonia and unexplained high fever [Chawla et al., 2008; Arrow, 2009; Alaluusua, 2010].
The minimum time period effective enough to cause abnormal ameloblast
function is likely to depend on the sensitivity of the ameloblasts
to the harmful factor and the power/concentration of this factor.
Even though, dental epithelial stem cells contribute in the regeneration of ameloblasts
in rodents, these cells differ from human teeth, as dental epithelial stem cells are lost after eruption of the tooth.
(11) Moreover, GHRL has been found in saliva as well as cells and tissues of the tooth germ, such as the inner enamel epithelium, mesenchymal cells, ameloblasts
, odontoblasts, and Hertwig's epithelial root sheath.
During the intrauterine life, the chronic deficiency of vitamins, particularly vitamin D, is one of the factors related to the changes in the function of ameloblasts
and formation of DDE (8).
Enamel production, which is controlled by ameloblasts
, is a rhythmical apposition of the enamel matrix (Goodman and Rose 1990, 1991).