Fixation effects on the fine structure of enamel crystal—matrix relationships

Decker, Jay D.

doi:10.1016/s0022-5320(73)90041-5

Cited by 28 publications

(18 citation statements)

References 21 publications

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“…He thus suggested that stippled material is a precursor of the organic stroma and that its stippled appearance "would then correspond to 'a three-dimensional network formed by blebs of organic material interconnected by thin' bridges." The concept that stippled material is a precursor to structured enamel matrix was further reinforced by Jessen (1968) and Decker (1973), who observed stippled material adjacent to elliptical tubular profiles. They proposed that stippled material gives rise to elliptical tubules, the interior of which provides a proper environment for crystal initiation and growth.…”

Section: Discussionmentioning

confidence: 93%

“…Stippled material was observed in the zone of presecretion (Reith, 1967;Kallenbach, 1971Kallenbach, , 1976Katchburian and Holt, 1972;Slavkin et al, 1976); in initial enamel secretion (Watson, 1960;Fearnhead, 1961;Reith, 1967;Kallenbach, 1971Kallenbach, , 1976Katchburian and Holt, 1972;Slavkin et al, 1976); in inner enamel secretion (Watson, 1960;Reith, 1967;Garant and Nalbandian, 1968;Jessen, 1968;Elwood and Bernstein, 1968;Matthiessen and Bulow, 1969;Katchburian and Holt, 1972;Kallenbach, 1973Kallenbach, ,1977; in outer enamel secretion (Garant and Nalbandian, 1968;Jessen, 1968;Decker, 1973); and in forming enamel in man (Ronnholm, 1962a,b), calf (Travis and Glimcher, 19641, and opossum (Lester, 1970). Slavkin et al (1976) also found that [3H]-tryptophan, used as a marker for enamel proteins, is incorporated by ameloblasts, migrates intracellularly, is secreted, and localizes over a "coarse-textured granular material that was subsequently transformed into the amorphous enamel matrix material with the associated formation of the calcium hydroxyapatite crystal nucleation site."…”

Section: Discussionmentioning

confidence: 97%

“…Some authors fixed by immersion in glutaraldehyde or glutaraldehyde-formaldehyde mixture (Garant and Nalbandian, 1968;Matthiessen and Bulow, 1969;Lester, 1970;Katchburian and Holt, 1972;Decker, 1973;Slavkin et al, 1976). Only a few studies used teeth fixed by whole body perfusion (Jessen, 1968;Kallenbach, 1971Kallenbach, , 1973Kallenbach, , 1976Kallenbach, , 1977.…”

Section: Discussionmentioning

confidence: 99%

“…Patches of granular material (gm) are found in this space at places where the process membrane invaginates (igs, interrod growth sites). x 14,573. enamel secretion (Garant and Nalbandian, 1968;Jessen, 1968;Decker, 1973); and in forming enamel in man (Ronnholm, 1962a,b), calf (Travis and Glimcher, 19641, and opossum (Lester, 1970). Slavkin et al (1976) also found that [3H]-tryptophan, used as a marker for enamel proteins, is incorporated by ameloblasts, migrates intracellularly, is secreted, and localizes over a "coarse-textured granular material that was subsequently transformed into the amorphous enamel matrix material with the associated formation of the calcium hydroxyapatite crystal nucleation site."…”

Section: Discussionmentioning

confidence: 99%

“…Ronnholm (1962a,b) suggested that "stippled material is a precursor of the organic stroma," which appeared as thin long septae interconnected by cross-bridges (Ronnholm, 1962b). The presence of stippled material has been reported in a variety of species by other investigators (Decker, 1973;Elwood and Bernstein, 1968;Garant and Nalbandian, 1968;Jessen, 1968;Kallenbach, 1971Kallenbach, , 1973Kallenbach, , 1976Lester, 1970;Matthiessen and Bulow, 1969;Nylen et al, 1972;Reith, 1960Reith, , 1967Slavkin et al, 1976;Travis and Glimcher, 1964). However, most of these studies used immersion fixation and slow penetrating fixatives such as osmium tetroxide.…”

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confidence: 99%

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Relationship between the quality of fixation and the presence of stippled material in newly formed enamel of the rat incisor

Nanci

Warshawsky

1984

Anat. Rec.

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Extracellular accumulation of a granular material that is presumed to be an organic "precursor" to mineralized enamel has been reported. This material, generally referred to as ""stippled material," was observed mainly after immersion fixation with osmium tetroxide. In studies with perfusion fixation, the presence of stippled material was inconsistent. Therefore, it appeared that the occurrence of stippled material was dependent on the method of fixation. To test this assumption, tissues were fixed by immersion in either osmium tetroxide or glutaraldehyde and by perfusion with either glutaraldehyde or a mixture of acrolein, glutaraldehyde, and formaldehyde. It was found that as the quality of cellular preservation improved, the occurrence of stippled material decreased. Since no stippled material could be found in material judged to be well fixed, it was concluded that stippled material is not an extracellular precursor to mineralized enamel, but is a breakdown product resulting from poor fixation.

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Section: Discussionmentioning

confidence: 93%

Section: Discussionmentioning

confidence: 97%

Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

mentioning

confidence: 99%

See 3 more Smart Citations

Relationship between the quality of fixation and the presence of stippled material in newly formed enamel of the rat incisor

Nanci

Warshawsky

1984

Anat. Rec.

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A freeze‐fracture study of the topographic relationship between inner enamel‐secretory ameloblasts in the rat incisor

Warshawsky¹

1978

Am. J. Anat.

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A correlated study using freeze-fracture replicas and routine thin sectioning was done on the ameloblasts which secrete inner enamel in the rat incisor. These ameloblasts are columnar cells aligned in rows parallel to the cross-sectional plane of the incisor. Each cell has a Tomes' process a t its distal end which is contained within a cavity of interrod enamel. Tomes' processes of a particular row of cells are inclined towards the mesial side of the tooth, while those of the next row are inclined towards the lateral side, so that the processes cross each other a t 90". Freeze-fracture replicas were used to examine the surfaces of ameloblasts between adjacent rows and the surfaces of the cells within the row. Replicas of the surfaces between rows showed that ameloblasts are curved so that their proximal and distal ends (Tomes' processes) are both directed towards the same side of the tooth. The surface of each row bears the impression left upon it by the cells in the adjacent row which have been fractured away. This cell-impression is also curved, but in the opposite direction to the cells which it crosses. It was thus shown that not only the Tomes' processes of adjacent rows but the entire cell bodies cross one another. This crossing is slight a t the proximal ends of the cells, but marked a t the level of the distal junctional complex. At this level a cell from a particular row curves across several cells of the neighbouring row and forms large tight junctions with a t least two cells in that row. The proximal and distal junctional complexes form zones of tight junctions around the cell. The distal complex is more extensive than the proximal and the tight junctions are better developed between adjacent rows. Gap junctions are, however, larger between cells within the rows. The study demonstrated the effectiveness of freeze-fracture replicas in obtaining 3-dimensional details about ameloblast shape, and this information was used to evaluate the supposed movement of ameloblasts during inner enamel formation.The unique system provided by the continuously erupting rat incisor offers a convenient model in which to study the general process of amelogenesis (Reith, '61; Warshawsky, '68, '71; Warshawsky and Smith, '71; Kallenbach, '73). Despite the fact that more is known about amelogenesis in the rat incisor than in any other tooth system, the remaining problems related to the morphology of this particular tooth still preclude a full understanding of the process of enamel formation.In order to produce the entire thickness of the enamel layer, the ameloblasts must be displaced from their starting position on the dentin a t the future dentino-enamel junction. This suggests that as groups of ameloblasts produce enamel rods, they have to move away from the forming end of those rods in order to create room for their existence. In the rat incisor the cells in the region of inner enamel secretion are aligned in rows which run parallel to the cross-sectional plane of the incisor. The cells within each row produce curv...

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Ultrastructure of odontogenic cells during enameloid matrix synthesis in tooth buds from an elasmobranch, Raja erinacae

Prostak

Skobe

1988

Am. J. Anat.

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The ultrastructure of the inner dental epithelial cells (IDE) and odontoblasts in elasmobranch (Raja erinacae) tooth buds was investigated by transmission electron microscopy to determine what contribution each cell type makes to the forming enameloid matrix. Row II, early stage, IDE cells contained few organelles associated with protein synthesis, whereas preodontoblasts appeared competent to initiate extracellular matrix production. Row III IDE cells are also devoid of organelles related to secretory protein synthesis, although these IDE cells accumulated large pools of intracellular glycogen. The glycogen appeared to be packaged into vesicles and exocytosed into the lateral extracellular space toward the forming enameloid matrix. Row III odontoblasts had a morphology consistent with an active protein secretory cell. No procollagen granules were present within the odontoblasts, however, nor were many collagen fibers observed in the enameloid matrix. Instead, non-collagenous "giant" fibers having 17.5-nm periodic cross striations were associated with the invaginations of odontoblast cell processes. Giant fibers, which spanned a clear zone adjacent to the odontoblasts, terminated within the enameloid matrix. Smaller 25-nm-wide "unit" fibers emanated from the giant fiber tips to form the bulk of the enameloid matrix. The clear zone, which separated the odontoblasts from the enameloid matrix at early stages, diminished in size at later stages until the odontoblast processes were completely embedded in the enameloid matrix. Nascent enameloid crystallites were observed only after a layer of unmineralized predentin was deposited beneath fully formed enameloid matrix. The results suggest that the major constituent of the enameloid matrix in skates is a non-collagenous protein derived from the odontoblasts. The inner dental epithelial cells appear to contribute large quantities of carbohydrates to the forming enameloid matrix.

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Fixation effects on the fine structure of enamel crystal—matrix relationships

Cited by 28 publications

References 21 publications

Relationship between the quality of fixation and the presence of stippled material in newly formed enamel of the rat incisor

Relationship between the quality of fixation and the presence of stippled material in newly formed enamel of the rat incisor

A freeze‐fracture study of the topographic relationship between inner enamel‐secretory ameloblasts in the rat incisor

Ultrastructure of odontogenic cells during enameloid matrix synthesis in tooth buds from an elasmobranch, Raja erinacae

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