Human tooth development inner enamel epithelium) What follows is part of the initial 'enamel organ', the center of which is made up of stellate reticulum cells that serve to protect the enamel organ. This is all encased by the OEE layer. Other events occur during the bell stage. The dental lamina disintegrates, leaving the developing teeth completely separated from the epithelium of the oral cavity; the two will not join again until the final eruption of the tooth into the mouth. The crown of the tooth, which is influenced by the shape of the inner enamel epithelium, also takes shape during this stage.
Smear layer Smear layer The smear layer is a layer of microcrystalline and organic particle debris that is found spread on root canal walls after root canal instrumentation. It was first described in 1975 and much research has been performed since then to evaluate its importance in assisting or preventing the penetration of bacteria into the dentinal tubules. More broadly, it is the organic layer found over all hard tooth surfaces. Early studies of dentinal walls after cavity preparation performed by Brännström and Johnson (1974) showed the presence of a thin layer of debris that was 2 to 5 micrometres thick. In