Scanning electron microscopic studies of the rat incisor odontoblastema

Hansson, Hans; Linde, Anders; Nygren, Håkan

doi:10.1007/bf00219159

Cited by 9 publications

(2 citation statements)

References 10 publications

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“…The outer 5 m of the enamel is devoid of prisms [14]. The pre dentin area displays a spongy structure that contrasts with the compact appearance of the dentin [3]. In the rat incisors, the number of tubules in the incisal dentin was slightly less than that in the dentin of the middle part of the crown.…”

Section: Discussionmentioning

confidence: 97%

Morphological Evaluation of Rat Incisor Enamel and Dentin Induced by Pregnancy and Lactation using A Scanning Electron Microscope

Özbek

Dural

Kanlı

et al. 2009

The Journal of Veterinary Medical Science

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ABSTRACT. This study assessed the effects of pregnancy and lactation on the morphology of the dentine tubules and external enamel surface of rat incisor teeth using a scanning electron microscope (SEM) equipped with an energy dispersive x-ray (EDX) system. Twentyfour female Wistar rats were divided into three groups; group A rats were at the end of pregnancy, group B rats were in the post-lactation period and group C rats, the control group, were unmated. The outer enamel surface and openings of the dentine tubules at the neck regions of the incisors were observed under the SEM and photographed. Examination of the incisor teeth of pregnant and post-lactation rats revealed scratches on the enamel surface. There were few eroded areas and slight changes and the dentine tubules of the pregnant group were fully or partially occluded on the entire surface of the enamel in the lactating rats. Almost all dentine tubules of the rats in this group were open. During the study, EDX analysis of calcium, phosphate and magnesium was also performed at 20 kV and 0 degree tilt. The results of EDX analyses of magnesium were significantly lower in the pregnant group compared with the lactation and control groups for the dentine in the neck region (p<0.05). The calcium values increased in the lactation group compared with those of the rats in the other two groups (p<0.05). These results might indicate that changes during pregnancy and lactation affect the content and morphology of mineralized dental hard tissue.KEY WORDS: dentine, enamel, lactation, pregnancy, SEM.J. Vet. Med. Sci. 71(10): 1273-1277, 2009 The tooth is a convenient model for studying basic biological phenomena such as cell generation, cell differentiation and interaction, synthesis, secretion and organization and mineralization of extracellular matrices. Rat incisor teeth grow continuously and can exhibit all stages of tooth formation at any time. This characteristic makes them ideal models for enamel formation [4]. In addition, in dentine, dentinal tubules play an important role in transferring stimuli and irritants to the pulp. By way of this route and through diffusion in the liquid filling the tubules, various therapeutic agents applied locally to exposed dentin may also reach the pulp [1]. Zeni et al. [16] examined bone mass changes in the total, axial and appendicular skeleton as well as in the different subareas of the femur and tibia in rats kept on a diet including normal amounts of calcium. Their experimental study using dual energy absorptiometry in vivo to visualize changes in BMD during the reproductive cycle of the rat showed that normal pregnancy in the rat appears to have little influence on bone, whereas lactation induces significant bone loss, mainly in areas with predominant trabecular bone [16]. Moreover, Miller et al. [5] demonstrated that significant changes occur in the rates of dentin apposition in the continuously erupting incisors of rats during pregnancy and lactation. The rate of dentin apposition in the rat is known to be sensitive to e...

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Section: Discussionmentioning

confidence: 97%

Morphological Evaluation of Rat Incisor Enamel and Dentin Induced by Pregnancy and Lactation using A Scanning Electron Microscope

Özbek

Dural

Kanlı

et al. 2009

The Journal of Veterinary Medical Science

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“…However, the transplants may be specified as insogeneic since the rat strain, intralitter-mated for more than 40generations, represents an inbred strain by definition [cf. Falconer, 1966], The way the pulp tissue was removed from the pulp chamber evidently left the major part of the odontoblasts on the pulp surface [Rockert, 1964;Hanson et a!., 1975]. Such odontoblasts have been found to become necrotic following allogeneic transplantation of the pulp [Zussman, 1966], possibly as a result of a disruption of the odontoblastic processes at removal of the cells from the pulpal wall.…”

Section: Discussionmentioning

confidence: 99%

Differences in the osteoinductive potential of transplanted isogeneic dental structures of the rat

Luostarinen¹,

Rönning²

1977

Cells Tissues Organs

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Pulp tissue, enamel and incisal and basal dentine of the mandibular incisor were taken from one litter of rats and transplanted subcutaneously or intracerebrally to sex-matched, 5-day-old animals of the subsequent litter of the same parents. As sham-operations the mere transplantation instrument was inserted into the transplantation sites. With some exceptions, the host animals were killed 4, 32, 128–138 and 210 days after the operation and the transplantation sites were examined either grossly or microscopically or both. The pulp tissue transplantation had resulted in formation of osseous tissue observed 128 days post-operatively. Bone was found in association with many of the basal dentine transplants 128–210 days after their insertion whereas no such tissue was observed with the transplanted enamel of incisal dentine. The sham-operation seemed to have elicited intracerebral bone formation in two animals. The osteoinductive activity of the transplanted tissues seemed reduced by their mineral phase. Further, in contrast to deminerahzed hard tissues, the non-demineralized inductive agents do not seem to possess bone morphogenetic properties.

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Ultrastructural localisation of proteoglycans in the odontoblast-predentin region of rat incisor

1976

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The localization of proteoglycans in the predentin of the rat incisor was investigated by ultrastructural histochemistry. Ruthenium red stained the cell coat of the odontoblasts as well as intracellular vesicles. There was also a staining of the extracellular matrix, but not of collagen fibers in the predentin. Treatment with the enzyme hyaluronidase prior to staining with ruthenium red abolished the staining of the vesicles and the extracellular matrix but not that of the cell coat. Bismuth nitrate and phosphotungstic acid gave similar staining of odontoblast vesicles and extracellular matrix. It is likely that the stained structures contain proteoglycans. The importance of these proteoglycans and their ultrastructural localization are discussed in relation to intracellular transport and the calcification process.

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Scanning electron microscopic studies of the rat incisor odontoblastema

Cited by 9 publications

References 10 publications

Morphological Evaluation of Rat Incisor Enamel and Dentin Induced by Pregnancy and Lactation using A Scanning Electron Microscope

Morphological Evaluation of Rat Incisor Enamel and Dentin Induced by Pregnancy and Lactation using A Scanning Electron Microscope

Differences in the osteoinductive potential of transplanted isogeneic dental structures of the rat

Ultrastructural localisation of proteoglycans in the odontoblast-predentin region of rat incisor

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