scholarly journals Dentinal mineralization is not limited in the mineralization front but occurs along with the entire odontoblast process

2018 ◽  
Vol 14 (7) ◽  
pp. 693-704 ◽  
Author(s):  
C. Li ◽  
Y. Jing ◽  
K. Wang ◽  
Y. Ren ◽  
X. Liu ◽  
...  
Keyword(s):  
Odontoblast Process

scholarly journals SYNTHESIS, MIGRATION, AND RELEASE OF PRECURSOR COLLAGEN BY ODONTOBLASTS AS VISUALIZED BY RADIOAUTOGRAPHY AFTER [3H]PROLINE ADMINISTRATION

1974 ◽  
Vol 60 (1) ◽  
pp. 92-127 ◽  
Author(s):  
Melvyn Weinstock ◽  
C. P. Leblond
Keyword(s):  
Electron Microscopy ◽  
Endoplasmic Reticulum ◽  
Golgi Apparatus ◽  
Phosphotungstic Acid ◽  
Secretory Granules ◽  
Low Ph ◽  
Collagen Fibrils ◽  
Dentin Collagen ◽  
Odontoblast Process ◽  
High Radioactivity

The elaboration of dentin collagen precursors by the odontoblasts in the incisor teeth of 30–40-g rats was investigated by electron microscopy, histochemistry, and radioautography after intravenous injection of tritium-labeled proline. At 2 min after injection, when the labeling of blood proline was high, radioactivity was restricted to the rough endoplasmic reticulum, indicating that it is the site of synthesis of the polypeptide precursors of collagen, the pro-alpha chains. At 10 min, when the labeling of blood proline had already declined, radioactivity was observed in spherical portions of Golgi saccules containing entangled threads, and, at 20 min, radioactivity appeared in cylindrical portions containing aggregates of parallel threads. The parallel threads measured 280–350 nm in length and stained with the low pH-phosphotungstic acid technique for carbohydrate and with the silver methenamine technique for aldehydes (as did extracellular collagen fibrils). The passage of label from spherical to cylindrical Golgi portions is associated with the reorganization of entangled into parallel threads, which is interpreted as the packing of procollagen molecules. Between 20 and 30 min, prosecretory and secretory granules respectively became labeled. These results indicate that the cylindrical portions of Golgi saccules transform into prosecretory and subsequently into secretory granules. Within these granules, the parallel threads, believed to be procollagen molecules, are transported to the odontoblast process. At 90 min and 4 h after injection, label was present in predentin, indicating that the labeled content of secretory granules had been released into predentin. This occurred by exocytosis as evidenced by the presence of secretory granules in fusion with the plasmalemma of the odontoblast process. It is proposed that pro-alpha chains give rise to procollagen molecules which assemble into parallel aggregates in the Golgi apparatus. Procollagen molecules are then transported within secretory granules to the odontoblast process and released by exocytosis. In predentin procollagen molecules would give rise to tropocollagen molecules, which would then polymerize into collagen fibrils.

The Extent of the Odontoblast Process in Normal and Carious Human Dentin

1983 ◽  
Vol 62 (7) ◽  
pp. 798-802 ◽  
Author(s):  
T. Yamada ◽  
K. Nakamura ◽  
M. Iwaku ◽  
T. Fusayama
Keyword(s):  
Human Dentin ◽  
Odontoblast Process

scholarly journals Odontoblast processes in dentin revealed by fluorescent Di-I.

1995 ◽  
Vol 43 (2) ◽  
pp. 159-168 ◽  
Author(s):  
M R Byers ◽  
A Sugaya
Keyword(s):  
Electron Microscopy ◽  
Confocal Microscopy ◽  
Cell Structure ◽  
Carbocyanine Dyes ◽  
Carbocyanine Dye ◽  
Reparative Dentin ◽  
Hard Tissues ◽  
Odontoblast Process ◽  
Odontoblast Processes ◽  
Rat Molars

There has been controversy about the length and structure of the odontoblast process within dentin since the earliest histologic studies of teeth. Our objective was to use the fluorescent carbocyanine dye Di-I combined with a new gelatin embedment procedure and confocal microscopy to determine the structure and extent of odontoblast processes in developing and mature rat teeth, injured rat molars, reparative dentin, and adult monkey teeth. We found that odontoblast processes do not extend into outer dentin or to the dentin-enamel junction except during early stages of development. Those in innervated regions of crown are long and straight, whereas those in roots are extensively branched and shorter. Cavity injury to crown dentin caused odontoblast fragments to be aspirated into outer dentin. In reparative dentin the odontoblast processes were branched and similar to those in roots. We used photoconversion and electron microscopy to show that Di-I fills the entire odontoblast after gelatin embedment, including the cytoplasm. This is a different type of carbocyanine staining from any previously reported, and it also stains other cells in adjacent hard tissues such as bone and cementum. The Di-I-gelatin method is a new way to use carbocyanine dyes. It has enabled us to solve a long-standing controversy about the histology of teeth, and it should be useful for many other studies of cell structure.

Terminal end of the odontoblast process

1988 ◽  
Vol 14 (11) ◽  
pp. 543-545 ◽  
Author(s):  
Michael J. Sigal ◽  
Robert Chernecky
Keyword(s):  
Odontoblast Process

scholarly journals CPNE7-Induced Autophagy Restores the Physiological Function of Mature Odontoblasts

2021 ◽  
Vol 9 ◽  
Author(s):  
Yeoung-Hyun Park ◽  
Chul Son ◽  
You-Mi Seo ◽  
Yoon Seon Lee ◽  
Alix Har ◽  
...  
Keyword(s):  
Cellular Activity ◽  
Human Dental Pulp Cells ◽  
Tooth Structure ◽  
Odontoblast Differentiation ◽  
Human Dental Pulp ◽  
Proper Functions ◽  
Dentin Formation ◽  
Odontoblast Process ◽  
Mitotic Cells

Dentin, which composes most of the tooth structure, is formed by odontoblasts, long-lived post-mitotic cells maintained throughout the entire life of the tooth. In mature odontoblasts, however, cellular activity is significantly weakened. Therefore, it is important to augment the cellular activity of mature odontoblasts to regenerate physiological dentin; however, no molecule regulating the cellular activity of mature odontoblasts has yet been identified. Here, we suggest that copine-7 (CPNE7) can reactivate the lost functions of mature odontoblasts by inducing autophagy. CPNE7 was observed to elevate the expression of microtubule-associated protein light chain 3-II (LC3-II), an autophagy marker, and autophagosome formation in the pre-odontoblast and mature odontoblast stages of human dental pulp cells. CPNE7-induced autophagy upregulated DSP and DMP-1, odontoblast differentiation and mineralization markers, and augmented dentin formation in mature odontoblasts. Furthermore, CPNE7 also upregulated NESTIN and TAU, which are expressed in the physiological odontoblast process, and stimulated the elongation of the odontoblast process by inducing autophagy. Moreover, lipofuscin, which progressively accumulates in long-lived post-mitotic cells and hinders their proper functions, was observed to be removed in recombinant CPNE7-treated mature odontoblasts. Thus, CPNE7-induced autophagy reactivated the function of mature odontoblasts and promoted the formation of physiological dentin in vivo. On the other hand, the well-known autophagy inducer, rapamycin, promoted odontoblast differentiation in pre-odontoblasts but did not properly reactivate the function of mature odontoblasts. These findings provide evidence that CPNE7 functionally reactivates mature odontoblasts and introduce its potential for dentinal loss-targeted clinical applications.

Scanning electron microscope observation of the endings of the odontoblast process in human and animal dentin

1984 ◽  
Vol 42 ◽  
pp. 240-241
Author(s):  
R. Chernecky ◽  
D.C. Smith
Keyword(s):  
Outer Part ◽  
Close Relation ◽  
Aqueous Alcohol ◽  
Dentinal Tubules ◽  
All Solutions ◽  
Cacodylate Buffer ◽  
Spherical Structures ◽  
Odontoblast Process ◽  
Odontoblast Processes ◽  
Scanning Electron

Recent SEM studies have demonstrated that the odontoblast process occupies the dentinal tubules of fully formed dentin, up to the dentinal-enamel junction (Maniatopoulos and Smith, 1982, 1983; Yamada et al, 1983). There is however, still debate on how the processes end at the dentinal-enamel or dentinal-cementum junction. It was the purpose of this study to investigate the endings of the odontoblast process in these areas.Materials and Methods:Freshly extracted human and rat teeth were a) split mechanically by the use of a mallet and a chisel, b) decalcified in 18% E.D. T.A. for 6 hr, c) washed in PBS for 1 hr, d) digested with bacterial collagenase for 2 hr at 37°C, e) fixed in 2% glutaraldehyde with 0.1M cacodylate buffer for 12 hr, f) post-fixed in 1% osmium, g) dehydrated in a graded series of aqueous alcohol. All solutions had 0.1M sucrose added to maintain almost near physiological osmolarity, ph was 7.4. Then specimens were routinely processed for scanning electron microscopy (ISI-60).Results:Odontoblast processes were observed in the inner, middle and outer part of dentin, up to the dentin-enamel or dentino-cementum junction, in all specimens examined. These observations verify the findings of previous workers in the field. At the area of mantle dentin the odontoblast processes were observed to be divided, giving two or more terminal branches (schematically shown in fig 1-3). In this area the processes were observed to end forming spherical structures (fig 1-9). These spherical endings of the odontoblast processes were observed after the total removal of the enamel and part of the mantle dentin through demoralization. These structures were observed on the surface of the dentin in close relation to the openings of the dentinal tubules (fig 4,5,8 and 9) and presenting a true continuation to the odontoblast processes (fig 6,7). In some specimens (fig 5,6) spheres were collapsed probably due to specimen dehydration following fracture and SEM preparation, whereas in other specimens they appeared intact (fig 8,9). Some endings (fig 8,9) showed smaller spherical projections on the main sphere body. The spherical endings of the odontoblast processes were observed in both crown and root mantle dentin.Conclusions:The results suggest that i) the odontoblast processes occupy the full length of fully developed dentin in both human and rat teeth, up to the dentino-enamel or dentino-cementum junction, ii) The odontoblast processes end in the mantle dentin in the form of spherical structures.Acknowledgement:The authors are grateful to Dr. M. Sigal for the initial preparation of the specimens.

Another look at the odontoblast process

1984 ◽  
Vol 10 (11) ◽  
pp. 538-543 ◽  
Author(s):  
Lee T. Fox ◽  
E. Steve Senia ◽  
Jeanette Zeagler
Keyword(s):  
Odontoblast Process
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