Abstract
The aim of this work is to clarify the developmental mechanisms of the enamel structures (histogenesis) on the phylogeny, which is realized by the cytological and the histological background. On the animal evolution, the tooth developmental mechanism is essentially to analyze for to clarify the calcification, because the tooth enamel composed of about 95% over inorganic matrix, and the tooth morphology is based on the calcification.
On the enamel evolution, Hunter-Schreger band develops from a simple island patter to complex patterns with every species has own individuality. The enamel prism arrangement and course also evolve from a simple to complex types along with the phylogeny. These prism courses in Schreger bands are classified into 5 types (two of convergence and three of divergence) by 150 species of fossil and recent animal enamels. This phenomenon suggests the enamel structures are formed by the grouping ameloblast and the cell mobility. The author proposes the mobility, as the hypothesis of ameloblast ‘Grouping and Dancing’ . These mobilities are prove by the tooth development and the immunohistochemistry on next points; 1) The correlation between the ameloblasts and the enamel crystals (calcification), 2) The direct relationship between the ameloblast and the enamel structure, 3) The origin and development of Ameloblast ‘Grouping and Dancing’ , 4) Is there Ameloblast ‘Grouping and Dancing’ .
1) Calcification. The enamel crystal seeds and develops in enamelins, which forms the nano-tube (Nano-space theory). The tube arranges almost perpendicular against the cell membrane of Tomes process with the affinity. Thus the crystal orientation is decided. The organic matrix of enamel is dissolved and the crystal growing space increases and regulates the crystal form.
2) Relationship between ameloblasts and enamel structures. It is observed both the enamel and the ameloblast as double layer in the thick (about 50 or more) and almost tangential sections against the enamel and the ameloblast. Each ameloblast group corresponds to a zone of Schreger bands on the developing enamel. Those grouped ameloblasts is a part of clusters of the enamel organ from the outer enamel epithelium to the ameloblast. It suggests the whole enamel organ harmonically moves with ‘Grouping and Dancing’ .
3) The development of ‘Grouping and Dancing’ . The initial group arises in the early developing inner enamel epithelium. The stratum intermedium cells develop on these mass of the inner enamel epithelium cell (ameloblasts) and connects to the outer enamel epithelium cell groups through newly developed enamel cords. These show the group is associated with other cells of whole enamel organ, which has the harmonical mobility with ‘Grouping and Dancing’ .
4) ‘Grouping and Dancing’. The anti-actin reaction is clearly provides the ameloblast groups which corresponds to zone of Schreger bands. Some cell masses have no-reaction against the anti-actin. The anti-actin reaction cell groups differents from anti-Keratin reacted cell groups on the enamel organ. There are also no reacted cell groups against the keratin. These suggest the keratin and the actin alternately and rhythmically changes the reaction in the enamel organ. Tubulin reacts all ameloblast layer avoid of some ameloblasts and Tomes processes. This also suggests the ameloblast plays the periodical and rhythmical secretion. Desmoplakin reaction shows from the stratum intermedium side of the ameloblast layer to the outer enamel epithelium. It shows these areas softly fixes from the enamel organ mobility.
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https://ror.org/05jk51a88 
