Scanning electron microscopy of the lateral cell surfaces of rat incisor ameloblasts.

Dry dissected rat incisor ameloblasts studied in the scanning electron microscope show remarkable specializations of their lateral surfaces. Four or five cycles of a change from a surface with longitudinal gutterlike folds associated with large intercellular spaces, to one with microvilli and reduced intercellular spaces, are found along the length of the lower incisor maturation zone. It is argued that these changes indicate cyclical activity in maturation ameloblasts.