Electron-microscopic observations on sound human dentine

Scanning electron microscopic observations of dentinal tubules in interglobular dentin.

“…ARWILL et al [19] and JOHANSEN et al [8] report that the membranous structure of the walls in dentinal tubules has a relationship with the dentin matrix and odontoblasts. PRovENzA [20] reports that the membranous structure originated from the peritubular filament remaining without calcification.…”

“…JOHANSEN et al [8], FRANK [9], MAJOR [10], FURSETH et al [11], GARANT [12] and YosmE [13] observed the fibrils running longitudinally in the dentinal tubules with both transmission and scanning electron microscopes. The authors concluded the fibrils mentioned in (1) are the same as those observed by them.…”

Organic Structures of the Hypercalcified Peritubular Matrix in Horse Dentine

“…5, 8], Takuma [4] found by using TEM on the replicas that the inner organic sheath contained collagen fibrils with regular 64-nm striations, and Isokawa et al [9] showed tubular membranous structures of a fibrous feltwork in it by scanning electron microscopy (SEM). Reliable evidence on the fibrillar outer organic sheath, however, has not been reported [1.5], although the outer organic sheath which did not show fibrils was faintly observed in the half-decalcified ultrathin sections [ 10] as well as in the replicas previously reported [2,7], For morphological studies of the PM in human dentine, various acids have been used, for example formic acid, for mic acid-sodium citrate, hydrochloric acid, nitric acid and phosphotungstic acid, and as a result the organic structures within the PM showed fine fibrils [2,7], a feltwork of deli cate fibrils [5], a low density of amorphous substance [8] and matrix fibres [9] by TEM or SEM.…”

“…Bradford (I] summarized that the hypercalcified peripheral region was surrounded with inner and outer hypocalcified layers and that a hypercalcified region and radial filaments existed between them. By transmission electron-microscopic (TEM) observations, the peripheral region was termed a calcified sheath [21. peritubular den tine [3], a peritubular matrix |4| and a pericanalicular zone [5], In this study the term peritubular matrix (PM) will be used for the peripheral region; in addition, the term inter tubular matrix (IM) will be used for the region composed of calcified collagen fibrils [4][5][6].…”

Studies on dentin

“…19711 finding a lack of firm relationship between fiber direction and direction of dentinal tubules, in that while such a relationship is more usually observed in the roots, in the crown the fibers become increasingly parallel to the tubules, especially at the cusps. Some find that the majority of dentinal collagen fibrils 'were dispersed in a direction parallel to the odontoblastic process, although isolated individual fibrils and an occasional group of fibrils followed a perpendicular course' [ J ohansen and Parks, 1962], The electron microscope data of J ohnson and P oole [1967] show fibrils parallel to tubules, especially' in the steep rat molar cusps, while the fibrils were essentially perpendicular to the tubules in rat incisors, suggesting that tubules play no significant role in orienting the fibrils which are laid down in 'sheets of randomly J ohansen [1967] describes a 'trellis-like fell work' of fibrils which may follow random courses in relation to the long axis of the odontoblastic processes. However, all of the collagen network forms a 'continuous structure throughout the dentine ... without inter ruption ...'.…”