SCANNING ELECTRON-MICROSCOPE AND MICRO-RADIOGRAPHIC STUDY OF CLOSURE OF HUMAN CORONAL DENTINAL TUBULES RELATED TO OCCLUSAL ATTRITION AND CARIES

Mendis and Darling (1979) studied the closure of dentinal tubules in relation to occlusal attrition by microradiography. An investigation of similar teeth using scanning electron microscopy (SEM) has now been carried out and includes the dentinal tubules involved in cervical toothbrush abrasion and dental caries. Thirteen canine teeth were used for SEM of occlusal attrition. Nine were fractured transversely and 4 longitudinally. For caries, 11 teeth were studied by optical microscopy and microradiography and 5 by SEM. Two examples of toothbrush abrasion were examined by SEM. Volume fraction analysis of SEM photographs of occlusal attrition showed that the pattern of tubule closure was similar to that from microradiography. In longitudinal fractures of attrition, the tubules at the worn surface were completely occluded. Below the zone of closure, the tubules were lined by peritubular dentine as in normal dentine but much of the tubular lumen was filled with cuboid or rhomboid crystals of various sizes. In SEM of caries, most of the tubules of the translucent zone were closed. The amount of peritubular dentine was similar to that in normal non-carious dentine and the remaining lumen was occluded by a rod-like plug of granular structure not continuous with peritubular dentine. In abrasion, SEM of longitudinal fractures showed the surface was homogeneous with completely occluded tubules. Beneath this surface layer, most tubules were empty. The findings were consistent with the earlier microradiographic ones. © 1979.