Ultrastructure of human dentine 40 years ago - progress and perspectives

In the 1959 premier issue of the Archives of Oral Biology, the first TEM ob servations were presented of sections of undecalcified human mature dentine produced with diamond knives. The odontoblast process was clearly shown to be a cytoplasmic extension of the odontoblast. The peritubular dentine app eared to be more calcified than the intertubular dentine and contained hydr oxyapatite as demonstrated by selective area electron diffraction. In the 4 0 years which followed, significant progress was made in TEM methodology, i ncluding improvements in fixation and embedding, development of ultrastruct ural cytochemistry and immunocytochemistry. and the use of electron microsc ope autoradiography. Additionally, we saw the advent of SEM and HRTEM. Thus , better knowledge was gained of (1) the odontoblast and its process and th e lamina limitans, (2) the dentinal nerve fibrils and (3) the HRTEM aspects of dentine. Interestingly, to the present day, diamond knives have continu ed to serve as the best tool for preparing thin sections of non-decalcified mature hard tissue for TEM and HRTEM, not only for dentine but also for bo ne, enamel and cementum. (C) 1999 Elsevier Science Ltd. All rights reserved .