EARLY BELL STAGE
By the 14th week, further morphodifferentiation and histodifferentiation of the tooth germ.
Internal enamel epithelium broadly maps out the occlusal pattern of the crown of the tooth.
The mapping is related to differential mitosis along the internal enamel epithelium.
The future cusps & incisal margins are sites of cell maturation associated with cessation of mitosis, but
areas corresponding to the fissures & margins of the tooth remain mitotically active. Thus, cusp height
is related more to continued downward growth at the margin and fissures than to upward extension of
the cusps.
During the bell stage, any bone resorption defects that restrict the space for development of the tooth
germ leads to changes in tooth shape. Consequently, spatial impediment, and the changing mechanical
forces that ensue, may be a co-factor in dental morphogenesis.