Comparison of cellular cementum in normal and diseased teeth-a scanning electron microscopic study

The cellular cementum, representative of normal and periapically diseased teeth, was examined under the scanning electron microscope. All specimens were fractured and left untreated with the organic compo- nent intact to obtain a cross sectional view of the cellular cenlentum. Our findings were as follows: The diseased cellular cementum contained more projections, more cementum lacunae, and fewer fibers compared with normal cellular cementum, which indicated increased calcification. Cemental resorption was also a consistent observation. An interrupted, uniform, amorphous layer or zone was seen in all the diseased specimens. It was located along the periphery of the fractured cellular cementum and seemed to follow the outline of the periapical lesion associated with the tooth. The diseased cellular cementum! contained a higher Ca and lower P level than the normal specimens, as seen thru the energy dispersive X-ray spectrometry. The amorphous laver or zone had higher P and lower Ca levels than its underlying diseased cellular cementum. This amorphous layer is a pathologic entity, and its signilicance at this time is unknown.