Figure 7

Haematoxylin and eosin staining of the first and second molar regions in the mandibles from 14-day-old (P14) mice. (a) In the normal (control) mice, the reduced enamel epithelium in the cusp tip region of the mandibular first molar fused with the oral epithelium, and the cusp tips (arrows) were about to emerge in the oral cavity. (b) In the cKO mice, there was still a great distance between the crown of the first molar and the oral cavity; the void space (VS) contained tissue/cellular debris (yellow asterisks), which appeared to have fallen into the cavity from the surrounding soft tissues. Scale bars, 200 μm in both images. cKO, conditional knock out; Ctrl, control; VS, void space.