In cap stage, regulating factor for cusp shape formation is present in

Enamel Knot: The cells in the center of the enamel organ are densely packed to form enamel knot. Enamel cord: It is the vertical extension of the enamel knot. Enamel Septum: The enamel cord extends to meet the outer enamel epithelium and form enamel septum. Enamel Navel: It is the small depression at the point of meeting of enamel cord and outer enamel epithelium. Enamel niche is the apparent structure created by the plane of histological sections cutting through a curved dental lamina so that mesenchyme is surrounded by the dental epithelium. It appears as a double attachment of dental lamina to the overlying epithelium. Recent studies shows that enamel knot acts as a signaling center expressing growth factors which play an important role in determining the shape of the tooth