[Scanning electron microscopy of the surface of human cementum in various physiological and pathological conditions]

In scanning electron microscopy (SEM) of the dental root surfaces human cementum resorption by giant multinucleated cells appeared similar in temporary and permanent teeth. Thus the resorbed zones were formed by associated Howship lacunae. On the lacunae walls, the openings of numerous tubules of the cementocytic lacunae were seen. Such aspects were noted during the physiological resorption of temporary teeth. The cementum surface of permanent teeth without pathology, presented frequently such resorption aspects around their apical regions as well as on other regions, the resorbed areas being more often not widespread. Similar resorption zones were observed in contact with paradental granulomas and along granulation tissue in cases of chronic periodontitis. Orally exposed cementum, after gingival recession, was mainly characterized by the disappearance of the typical dappled aspect of the cellular cementum and by the presence on the smoothed surface of numerous striate. The cementum wall of the periodontal pockets showed always the dappled aspect with the occasional presence of incipient calculus formation as well as calcified fibrillar elements. These calcified fibrils were either short covering the whole surface or were longer being disposed parallel to the surface in interwoven networks or in tufts. Cementum curetage followed by root planning removed the calculus completely. Before root planning, the presence of numerous striae were noted. They disappeared following the action of a rubber cup and an abrasive polishing paste. Ultrasonic scaling gave a relatively clean root surface. However, the cementum surface, apparently devoid fo calculus under visual examination, showed in places the presence of thin calculus layers under the SEM.